FWD vs RWD: Adders, Subtractors, and Weight, Oh my...! [Archive]

Greg Amy

01-18-2009, 02:26 PM

Over the last few months, there have been thread hijacks in regards to the adders/subtractors for FWD vs RWD car. I wanted to create this topic to bring the idea to the fore on its own.

To summarize, there are subjective class-specific "subtractors" applied to all FWD cars. Would someone in the ITAC please post exactly what those are? As I recall the value for ITS and ITR cars is 100#; is it 50# for the rest? The outstanding question is, are these numbers reasonable, and are they sound?

So, why a "subtractor" for front-wheel-drive (FWD)? In racing, FWD carries with it several disadvantages. First, because of mechanical design (the drivetrain is almost exclusively transversely-mounted, ahead of the front wheels) there is a significant frontward weight bias. In most cases, as much as 80% or more of the weight of the car is on the front wheels. On the other hand, with longitudinal mounting and the axle assembly in the back (and in some limited cases, even the transaxle in the back and possibly the engine mounted front-midships) a rear-wheel-drive (RWD) car has a much better weight distribution. As a result, you can easily imagine that the two front tires in a FWD car will be called upon to do most of the sideload (g-forces) work around a corner, whereas in the RWD the loads are more evenly distributed.

Second, in both a FWD and RWD car, the front wheels steer the car via higher slip angle (i.e., the front wheels turn, the rear don't). Therefore, in a FWD car not only do the front tires have to deal with a lot of the side loads around the corner, they also have higher slip angles to steer the car.

Third, obviously a FWD car has to apply forward acceleration force through the front tires to accelerate the car, whereas the RWD car applies forward acceleration force through the rear tires. So to make matters worse, not only does the FWD car have higher side loads on the front tires, and has to steer the car with a higher slip angle, it also need to apply forward propulsion!

Fourth, weight transfer. As a RWD'er is applying that acceleration force, g-forces are transferring weight onto the driven wheels just as they need that traction, and off of the steering wheels just as they are no logner needed. At the same time, the FWD'er is applying acceleration forces and transferring weight off of the only tires that are doing anything!

That's a LOT to ask for two small patches of rubber. And through all this, the rear tires are wondering "uh, what am I supposed to be doing?" It's been said - I think Kal Showket was the first to quip this - that there's only two purposes for the rear tires on a FWD car: to make it look good on a used car lot, and to keep the fuel tank from sparking on the ground while it's driving...

If you can imagine all this, then you can imagine why racing a FWD car seems an exercise in futility; it's almost like racing with only two tires instead of four (and in pretty much all cases of FWD prep we intentionally destroy the rear tire grip in order to offer some semblance of handling balance). There's only so much that a pair of tires can do. Yet we do race FWD regardless. Why? Because normally FWD cars are given some "breaks" in attempt to even the performance disparity. Those "breaks" are almost always weight reductions; in some cases of pro racing they are power advantages. But it's generally accepted that similar-weight, similar-power FWD cars simply cannot compete in parity with RWD cars.

Keep in mind the three things that FWD tires do: side loads during cornering, slip angles during turning, and acceleration forces under power. The only one of the three where RWD and FWD are in parity is the steering; under side load the FWD carries a greater percentage of the total load, and under acceleration the tires have to share acceleration loads with the side loads. Remember the friction circle? Very simply put, there's only "so many g's" available from those front tires; if the fronts have to resist more mass they can't put out as many g's, and if they also need to accelerate they have to give up even more of that g-loading to share with the engine.

Try to do both too much and they give up and the car understeers. To compensate a FWD'er will, as noted, hose the rear grip of the car. I don't think there's really one person that thinks this is a performance advantage, but it's better than getting into the "waiting game" of an understeering car, waiting for it to stop sliding before you can then accelerate/turn. An experience FWD'er will "toss" the car into the turn, starting a large yaw of the chassis in advance. This large slip angle from the rear tires will allow less slip angle from the tires to turn the car, thus leaving more g-force for side loads and/or acceleration. Every successful FWD car drives this way to some extent, known or not, from nearly imperceptible all the way to full-up "oh my garsh". The only other option is to drive slower through the turn such that the maximum available g-force of the tire is not exceeded.

A "well set-up" FWD car will also have minimal rear grip mid-corner to corner exit, such that as the pilot starts to feed in the throttle there is sufficient g-force left to accelerate out of the corner. This is unusual in most cases except in extreme car setups; in most cases a FWD'er will have to "wait" for the mid-corner side loads to begin diminishing, before he can begin to feed in the throttle, all in frustration as his RWD counterparts are already using their rear tires to full advantage, accelerating out of the corner.

So, to compete on a reasonable level with a RWD car, a FWD will car need at least one of three things: a power advantage, a weight advantage, or a grip advantage. A power advantage will allow the car to make up ground lost in the corner and on corner exit; a weight advantage will reduce the loads on the tires through the corner thus allowing the driver to corner faster and begin accelerating sooner on par with the RWD'er; a grip advantage (e.g., bigger tires) will give the FWD'er a larger friction circle to work with.

"But wait," you might ask. "I've gotten my butt kicked by FWD cars in low-grip conditions such as in the rain or ice racing; how can you make such a blanket statement?" This is a good point, but is not germane to the discussion of the 95th-percentile track condition. I won't go into the specific details of why a FWD is an advantage in low-grip conditions because we classify and weight our cars based on dry conditions, which is what most of us encounter most of the time. But, generally speaking , in condition of reduced coefficient of friction (Cf) this vertical load over the wheels becomes an advantage. Think pounds-per-square-inch; anyone that has driven a pickup truck in the snow knows that a few large bags of feed in the bed is a big advantage.

So how do we apply these concepts to Improved Touring? How can we determine reasonable and sound numbers? Right now the numbers are arbitrary, almost "throw a dart and see where it lands", with one (known to me) adjustment for higher horsepower classes (ITS and ITR). This tells me two things: one, it is truly subjective; and two, we at least recognized once that they weren't "right". Personally, I still think they're not quite there.

In another topic, One poster wrote (http://www.improvedtouring.com/forums/showpost.php?p=276816&postcount=34), "We can debate whether FWD may in fact be an advantage at lower hp levels..." And interesting concept, given the above discussion; FWD as an actual advantage? I responded with (http://www.improvedtouring.com/forums/showpost.php?p=276818&postcount=36):
There are two primary factors that make this so [in lower-horsepower clases]: increased weight of the RWD system vs. FWD as a percentage of the car's total weight, and the ability to put power down to the ground. In ITC, the marginal "cost" of a heavier RWD system far exceeds its benefits, and because of the lower power and torque [of ITC cars] there's less likelihood of breaking traction under power. [P]lus, [with the low torque] there just not a whole helluva lot of weight transfer (which is one of RWD's primary advantages). I'm sure this would float like a lead balloon, but the FWD "subtractor" in ITC could probably be eliminated.

In ITS and ITR, however, the marginal "cost" of a RWD system is far, far less a factor as a percentage of total weight, and [in FWD cars] the power available can easily exceed the traction capability of the front wheels...IMO, the "subtractor" for FWD on those two classes should be increased.
(Cont'd next message due to space restrictions...)

Greg Amy

01-18-2009, 02:27 PM

Let's discuss that idea a bit further. Let's take, for example, a pair of 50 HP ITC cars that weigh the same by "the process", one FWD one RWD. Keeping in mind my original concepts, the tires of the FWD car have to carry more of the side loads, but it's a lightweight car so not nearly as bad. Both cars use the front wheels to steer, though the FWD has a tad bit more slip angle due to the increased side load. But, with only 50 ft-lbs of torque to apply, geared, to the front wheels, The FWD'er doesn't really have to slow down nearly as much in the corner to apply full power coming out, so it's not too much of a disadvantage. Give him a few pounds' weight reduction for increased front tire loads and increased slip angle, but this one's easy.

Now, let's go to the other end of the spectrum, and compare an ITS Integra GS-R versus the Mazda RX-7 (I used these two cars not because it's what I drive, but because I don't know a RWD ITR car comparable in power to the Type R. If you do, please put it up as an example). These cars are both significantly heavier than the ITC example - but only have 1" more wheel width - and both put out significantly more power. Both are comparable in weight as classified. Both have much higher weight-to-available-tire grip levels than the ITC cars. As I believe you can easily imagine, the ITS FWD'er simply does not have the flexibility of available relative grip that the ITC'er does, and in most cases will have lower cornering speeds and will have to wait much longer before applying power on corner exit. As his RWD counterpart is rolling through the corners and rolling on the power to exit the corners, the FWD is slower through and out of the corners, managing the front tires.

We have implicitly agreed with these concepts by having lower subtractors for lower-hp classes. However, I don't think this "process" addresses the situation well at the extremes. Thought it's been suggested as above, I think you'll find a few (but not many) people that think the subtractor in ITC is excessive. But, 50# is a fair number, given that FWD'ers should get SOMETHING. Further, most will agree that ITA and ITB seem to be well-classified; the subtractor works out well for both ITB and ITA simply because of the wheel/tire rules: the subtractor is good at ITB horsepower levels with 6" wheels, and the increased wheel size in ITA accommodates the increased horsepower.

But, however, I think you'll find a lot more people think the subtractor is insufficient in ITS and possibly in ITR (though I recognize there's a wheel size increase; I don't know that it's been shown that FWD cars have the flexibility of taking taken advantage of the increased wheel sizes). And, I believe, that breakdown comes somewhere around a value of 150/160 (stock) horsepower.

For example, Kirk's ITB Golf puts out - what? - 115/120 hp? Once you've got that car turned into the corner you can pretty much flat-foot the throttle from the early apex out. My ITA Nissan was putting 155 ponies to the ground; through most corners I was just barely feathering the throttle from mid-corner out, and once I started opening up the wheel I could put the throttle down on most corners (except uphill exits like T3 at NHMS). The ITS Integra, on the other hand, is a strong case of "weight/wait management" (another Kal Showket term): I have to manage the forward-to-rear weight transfer significantly, and I have to wait-wait-wait before I can put the throttle down. All the while, competition is already on its way...

So, I hope that I've illustrated how the "problem" of FWD is one that is directly related to vehicle weight, available grip (tire/wheel size), and available power. Well, what to do about it?

I haven't begun to seriously think about the mathematics, but I believe the answer is not stepped and subjective subtractors, but numbers based on the physical characteristics of the car's classified weight and horsepower (not necessarily horsepower-to-weight). The more horsepower a car has, the higher its subtractor (and, inferentially via "the process", its classified weight). I suggest given our wheel size changes from ITB to ITA that a logarithmic scale may work, keeping ITC/B/A similar to what it is now (maybe giving the rear-wheel-drive cars in ITA a slight relative disadvantage) but increasing significantly as stock power outputs exceed 155/160 or so, giving ITS a better advantage, with ITR even more so.

"Wait," you may say. "Aren't we doing the same thing with the stepped subtractors?" Yes, we are. However there seems to be a whole lotta subjectiveness going on here. A reasoned, mathematical formula would ease a lot of minds on both sides, and melt resistance to the obvious-to-me need for increased subtractors in ITS and ITR. If you want to do it with a subjective stepped number, fine; but I think you'll end up with a lot of people arguing about it. In the end it was an objective mathematical formula that eroded opposition to the "Great Realignment"; there's just something about math and objectivity that people really like...

FWD in higher-horsepower cars is a significant disadvantage; go find a pro racing series with evenly-powered and -weighted FWD and RWD cars competing in parity. You won't. in all cases where FWD and RWD compete head-to-head successfully, there is some significant advantage being handed to the FWD'ers. And I can tell you from experience, it's not just 90 pounds...

GA

Andy Bettencourt

01-18-2009, 02:37 PM

I would suggest using this letter as a basis for your math excersize, and submitting it for consideration.

JeffYoung

01-18-2009, 02:38 PM

Ditto, and I'd like to see the math.

Gary L

01-18-2009, 03:02 PM

FWD in higher-horsepower cars is a significant disadvantage; go find a pro racing series with evenly-powered and -weighted FWD and RWD cars competing in parity. You won't. in all cases where FWD and RWD compete head-to-head successfully, there is some significant advantage being handed to the FWD'ers. And I can tell you from experience, it's not just 90 pounds...

GA
So, what are the basic numbers in WC Touring that make the Acura and Mazda FWD cars run with (and sometimes, away from) the BMW? I realize we're talking more hp here than the typical ITS car, but it should provide a clue as to where the outer limits might be, relative to the faster IT classes.

Greg Amy

01-18-2009, 03:04 PM

Ditto, and I'd like to see the math.
Well, ironically, the problem with the objective math in this application is...it's subjective. The end failure of such an exercise - and the root of my comment in another location stating it's likely pointless - is that it has to pass someone's subjective sniff test.

It's "easy" to use math to describe a natural phenomena: you measure many points of observation and use appropriate mathematics to predict it. Continue with enough points and eventually you're proven right or wrong. Math is nothing more a descriptive/predictive tool.

Using math in vehicle classifications is no different, except now you're asking me to predict in advance of observation, and at the same point of changing the observations from the existing norm. Said simply, for example, I'm telling you I want to make the subtractors higher for ITS, and possibly even higher than that for ITR, so I can assure you my mathematics will fit that premise. You can bet that any formula I provide to you will fir that base assumption. Problem is, I have no doubt my premise varies widely from yours, so you will, no doubt, reject the idea of formulation rather than rejecting the specific formula itself.

I presented the above treatise for two reasons: one, it's snowing outside and I'm bored; and two, I want the idea breached that the FWD subtractors in ITS and ITR need adjustment. "How much" is open for discussion, and once we have a few of those specific observations I'll be glad to provide to you a mathematical formula through which to remove subsequent subjective decisions.

For reference, provided as a subjective example, I think any FWD car with over 160 hp should have a minimum of a 150# weight advantage over a comparable RWD car if not more (and I'm talking in terms if dynamics only, given I cannot illustrate that premise with any reasonable and comparable on-track performance). Given no experience with ITR cars, I cannot speak to that; but I suggest given similar dynamics a formula can be derived using existing ITA/B/C examples, the above-suggested ITS example, and have that extended forward to ITR.

As I said, this could very easily go back to the whole ideal of stepped subtractors per category or horsepower bracket, especially given our tendency to "round down" to the nearest hundred (a different issue within itself). But the idea should be given consideration. - GA

Greg Amy

01-18-2009, 03:08 PM

So, what are the basic numbers in WC Touring that make the Acura and Mazda FWD cars run with (and sometimes, away from) the BMW?
Gary, WC is no longer a good example (at least, until 2009). They long-ago abandoned a standardized ruleset with weight adjustments, instead going to individual make/model performance adjustments, and significant mods varying from our IT prep. As such, their 2008 model doesn't work for us.

However, in 2009 they are slowly beginning a return to standardization and "minimal" modifications, and in the long run may offer us reasonable examples.

But, totally from memory, I recall from the late-90's a weight difference along the order of 200-250 pounds between the E36 BMWs and the Real Time Acura Type Rs (with prep reasonably-comparable to our ITR rule set). But that memory is fuzzy and subject to being completely out-and-out wrong. If someone has access to those rulesets, something from the 96-99 eera would be useful... - GA

lateapex911

01-18-2009, 03:13 PM

The biggest issue I see with drawing comparisons between WC Touring and IT is the cars use substantially different cages, and suspensions. The cages ties the structure together, so that incredible spring rates and dampers are feasable, and up to now, suspension points were far more open than IT.

dickita15

01-18-2009, 03:22 PM

I think real men drive RWD race cars and weight breaks for FWD is affirmative action.:D

ddewhurst

01-18-2009, 03:37 PM

Knestis

01-18-2009, 03:51 PM

Well, ironically, the problem with the objective math in this application is...it's subjective. The end failure of such an exercise - and the root of my comment in another location stating it's likely pointless - is that it has to pass someone's subjective sniff test. ...

But that's a policy issue, not a technical issue.

We HAVE to make some operative assumptions if we're going to have a repeatable process. We KNOW we won't be perfect. We've demonstrated that the membership we've heard from want us to be "more accurate" than we currently are. The policy question is, "How do we get appropriately close?"

I'd WAY rather make ONE set of assumptions, then let the numbers fall out for the individual cases, than to keep making new assumptions specific to make/model cases as they come up.

K

lateapex911

01-18-2009, 03:52 PM

Has anyone checked the FWD/RWD equator model used by the PAC/CRB for Production cars. Why not use the same model for the day when IT person wants to move to Production so that the move is transparent. :emgift:

Because they are different cars, with different suspension allowances, different tires, different power, and different chassis (cages). I'd think that the variables are enough to skew the result. If that's the case, then the benefit (ease of transfer) isn't worth the cost (applying an inaccurate factor, and screwing the category), especially when the transfer rate isn't all that high.

However, I would be interested to learn what the PAC process is. Can you share?

Andy Bettencourt

01-18-2009, 03:54 PM

This is a tough one to swallow. In order for their to be a change, we need to understand why 100lbs is 'wrong', and why your 150lbs is 'right'. Until we can make an educated decision on that, I don't know how anything can change.

I am all for getting things right but after all those words, I see no data to move forward with. I read everything you said and I agree with what you are saying in terms of subjectivity. The current 100lbs is subjective. Your 150lbs is subjective. The 50lbs it was prior to my proposal was subjective. Trying to suggest a new adders without reverse engineering your desire is going to be tough.

I will admit, 150lbs seems like a whole lot of weight given equal power and suspension design...but that is just my gut.

Even in Koni Challenge they monkey with too many factors to draw comparisions. The MX-5 we run is 2350lbs (without driver). The Mini Cooper S is 2200lbs. IIRC they both start right around 170hp. Problem is the Mazda is allowed open cams and an open ECU and the Mini is allowed a boost bump but an OEM ECU - and alternate rear control arm kit...

Gary L

01-18-2009, 04:01 PM

I think real men drive RWD race cars and weight breaks for FWD is affirmative action.:DAffirmative action my arse... it's communism! :)

tom91ita

01-18-2009, 04:29 PM

after reading the differences and advantages between RWD and FWD, i feel like an idiot for racing fwd.

except that i love my honda...

isn't there any track simulation software that could help with this on the math level? or maybe even some DL-1 data that could be reviewed?

just thinking out loud. i think it is an interesting math problem. if we thought that the fwd vs. rwd was worth x% g-force, we could start estimating corner speeds, etc.

also, is there any perceived straight line braking advantage to either car? my rear brakes do very little but i can also stab the brakes relatively hard and not have to "wait" for weight transfer to take place to let the front tires "load" up...

jlucas

01-18-2009, 04:43 PM

I'm not versed in it but Bosch LapSim could answer these questions. I've heard it can use DL1 data but I don't know the details.

It's free download but takes some time to figure out.

Bottom of the page:
http://www.bosch-motorsport.de/content/language2/html/3589.htm

tom91ita

01-18-2009, 05:19 PM

Jeremy,

i think this was the one i was thinking of but could not remember the who/when/where. thanks,

tom

MMiskoe

01-18-2009, 09:29 PM

FWIW, I don't see that it is out of line to at least look at this in terms of base weight of the car.

There are some 2700# FWD ITA cars, why do they get something different than the ITS car w/ the same weight? Or more likely the question is why do they get the same 100# as all the ITC cars at 2000# or less?

Not that I have an answer, as it is subjective at best. But then again so are any of the adders. I will say that what ever anal grab bag these numbers came from, its at least in the right ball park. Otherwise you'd never have anything even close.

Here's your starting point Greg. Go get yourself some vehicle like the Mitzu Eclipse or 3000GT which was offered in pretty much same trim but w/ FWD or AWD. Build up the two of them to a full IT prep, then go do some testing. You won't have a direct comparison to RWD, but you'll be on the right track. Maybe Ben will help you, he'll need another car before this time next year. All snide comments aside, I can't come up w/ any better plan to provide quantifiable answers.

Matt

JeffYoung

01-18-2009, 09:36 PM

That's true isn't it? Curb weight/race weight is going to have a significant impact as well, just like horsepower. A heavier FWD car 'suffers" more, right, regardless of power?

Xian

01-18-2009, 10:08 PM

Assuming both the cars run the same size front tire. Personally, tire size options is the main reason I think an ITR RSX (can fit 245's or possibly larger up front) has a better chance than an ITR Type R (225's up front are pretty much the max).

Christian

Andy Bettencourt

01-18-2009, 10:18 PM

FYI: Current process

ITA, ITB and ITC FWDers get a 50lb deduction just for being FWD.

ITS and ITR FWDers get a 100lb deduction.

Straight up, off the top, no questions asked.

lateapex911

01-18-2009, 11:45 PM

So, is the answer to grab a "median" car, assign it a weight value, say 100 pounds as it's 'adder', then apply it to other weights via a percentage?

So a car that would hit the class at say 2500 gets a 100 pound break, but a car that is 2800 before adders gets 112 pounds?

tom_sprecher

01-19-2009, 12:09 AM

I think real men drive RWD race cars and weight breaks for FWD is affirmative action.:D

While you jest, there is still a certain, albeit small, underlying truth to this statement.

hondaracer48

01-19-2009, 12:49 AM

Andy,
Are you saying that SCCA is working on giving the ITS GSR's another 100lbs off in addition to the 100lbs it received in 2007? I love the sound of that.

I do have some comments on what I read earlier on this thread. First, someone please explain why with everything mathematically pointing to the RWD as being superior, that the FWD cars are able to out brake the RWD cars? And I don't think that is just a personal opinion either. Second, I think the most important advantage to a road race car, whether it be a 1500lb or 3500lb one, is the balance of the car (with comparable horsepower of course). The more balanced the weight, the less amount of weight transfer that can push the tire beyond its cornering limits, at the same time the longer or earlier the driver will be able to accelerate. The longer the acceleration, the faster lap times. Lastly, I do believe that math is a priceless tool we can use in preparing a car or predicting its tendencies, but there is no one formula that will be consistant. There are just too many factors, which explains why many pro teams take their winning formula back to the same track, try all weekend making adjustments, and still end up in the back. It is however, our best shot, by repeating success. I think the current method of taking an educated guess, group these cars together, and see what happens works just fine. Until someone does come up with a 100% built ITS GSR (I'm almost there, but moving is forcing the sale of the car), it would be wasted time to argue about FWD/RWD advantages. I still personally believe that a 100% built ITS GSR at 2590lbs will be a dominating car.

Ed Chang
San Francisco Region

ekim952522000

01-19-2009, 01:04 AM

Since were all just brain storming how about just modifying the power to weight ratio for each class for FWD cars.

Example: Let's take four ITR cars and run them through the regular process.

ITR cars
93-96 Prelude 190*1.25*11.25 = 2671 - 100 = 2571
00-01 Type R 195*1.20*11.25 = 2633 - 100 = 2533
00-02 Celica 180*1.25*11.25 = 2531 - 150 (fwd w/struts) = 2381
91-95 Legend 230*1.25*11.25 = 3235 - 100 = 3135
02-03 RSX 200*1.25*11.25 = 2813 - 150 (fwd w/struts) = 2663

Now what if we took those same cars and kept everything the same but used a pw/wt ratio of 10.75 for fwd instead of 11.25

93-96 Prelude 190*1.25*10.75 = 2553
00-01 Type R 195*1.20*10.75= 2515
00-02 Celica 180*1.25*10.75 = 2418 - 50 (struts) = 2368
91-95 Legend 230*1.25*10.75 = 3090
02-03 RSX 200*1.25*10.75 = 2687 - 50 (struts) = 2637

So with just a quick guess of .50 adjustment of pw/wt ratio for FWD I got these results. The HP numbers are for projected IT HP

Celica 225hp
2381 - 2368 = 13

prelude 237.5hp
2571 - 2553 = 18

Type R 234hp
2533 - 2515 = 18

RSX 250hp
2663 - 2637 = 26

Legend 287.5hp
3135 - 3090 = 45

Anyways this was just a exercise to see what would happen as you can see it got pretty close to the existing ITR weights but as the FWD cars get more powerful the get slightly more of a weight break. Which seems to make since.

JoshS

01-19-2009, 02:16 AM

Holy cow everyone ... can't we keep it simple?

Sure, we can use a formula based on weight or horsepower or something to figure out the FWD subtractor, but if our baseline for a typical car is 50lbs or 100lbs (depending on class), then the new formula will still end up pretty darn close to the fixed subtractor we already have.

I say, keep it simple ... fixed numbers per class are close enough. Argue all you want if the fixed number is right or not, but please, can't we just keep the process SIMPLE? It's all an approximation anyway.

Changing the process might move some weights around +/- 50lbs (see Mike's math just above) but we'd have to assign new weights to every FWD car for not much adjustment. It's not worth it.

ekim952522000

01-19-2009, 02:22 AM

JeffYoung

01-19-2009, 08:19 AM

I totally agree with keep it simple.

I would also need a good answer to "what's broken" and "why are we doing this" before I would support it. If we need a good reason "why" in order to respect a member's request to remove a washer bottle, I think we need as much or more in order to change the fundmentals of the process.

Andy Bettencourt

01-19-2009, 09:13 AM

Andy,
Are you saying that SCCA is working on giving the ITS GSR's another 100lbs off in addition to the 100lbs it received in 2007? I love the sound of that.

No. Just describing how it works currently.

Greg Amy

01-19-2009, 11:36 AM

I hate marathon quoting sessions, but unfortunately this is the only way I can see to efficiently address multiple points, quickly.

I think real men drive RWD race cars and weight breaks for FWD is affirmative action.:D
Why do you hate the handicapped, Dick? ;) We're not a different race, Dick, we're "special".

In order for their to be a change, we need to understand why 100lbs is 'wrong', and why your 150lbs is 'right'. Until we can make an educated decision on that...The current 100lbs is subjective. Your 150lbs is subjective....but that is just my gut.
Agreed, Andy. I can't justify it mathematically, I can only give you a process to make it easier. Further, anything I offer will seem to be tainted with a selfish agenda (with the idea that it may actually require more than 150 pounds in the long run, but sometimes you only get one bite at the apple...) But, my gut has one extra "bit" that yours doesn't, and that's more years of the experience and education you're looking for, mostly in front-wheel-drive cars but a lot in RWD as well.

I can easily understand how lack of experience with FWD, coupled to having seen FWD perform well in some classes, would increase your skepticism. But you will have to resolve among yourselves how much of my stated judgment and opinion is potentially clouded with a selfish agenda. I see the same thing when opposed by those whose experience is primarily RWD. I'd like to think you'd understand how little of this actually is selfish, as I try to do as well for you.

after reading the differences and advantages between RWD and FWD, i feel like an idiot for racing fwd.

No need to. Understanding what you're up against is 3/4 of the battle, covered by, hopefully, reasonable breaks for the shortcomings of the platform.

also, is there any perceived straight line braking advantage to either car?Not simply due to FWD versus RWD. Braking is a function of weight transfer, brake size, and tire patch size, not drive location. It's one of the areas where neither platform, per se, has a distinct advantage. In fact, one could argue that because of the larger distribution of weight towards the back of the car, a RWD, mid-engine, or rear-transaxle car would have a significant weight transfer advantage (see Miata, Toyota MR-2, Porsche 911 and 944, etc).

Honestly, I've never heard, nor experienced, any braking advantages solely due to FWD. In fact, I always thought that with all that weight up front already it was a distinct disadvantage (which is why FWD cars have such piddly rear brakes; ain't much weight back there to begin with keep the tires on the ground; imagine transferring it all forwards and making only the front brakes and tires work...)

No, I suggest any perceived advantages are due primarily to the installed equipment (e.g., brake and tire sizes, weight), not the drive platform.

I will say that what ever anal grab bag these numbers came from, its at least in the right ball park. Otherwise you'd never have anything even close.
I would agree -- to a degree. But I suggest that your statement above comes from observation of ITA, ITB, and ITC which have numerous FWD cars entering. Further note that my discussion above focuses primarily on need for change within the higher-horsepower of ITS and ITR ranks, classes that have had very few FWD entries to use for illustrative comparison. As such, what I'm offering is predictions for change based on experience, knowledge, and education.

Go get yourself some vehicle like the Mitzu Eclipse or 3000GT which was offered in pretty much same trim but w/ FWD or AWD.Did that in Firehawk in the early 90s (which was pretty close to IT prep at the time). Once you add in all the extra equipment to make it FWD it becomes too heavy and robs too much power. Except in the rain, the FWD cars were always faster. Besides, adding AWD to a FWD car usually makes it a heavy, slow FWD car.

It's not a fair comparison. And, I'm unaware of any valid direct same-chassis FWD v RWD platforms.

Curb weight/race weight is going to have a significant impact as well, just like horsepower. A heavier FWD car 'suffers" more, right, regardless of power?
Of course. Remember, it's all about those two patches of rubber up front. You're asking those same-size two patches to do a helluva lot more work on a FWD car than a RWD car.

...why with everything mathematically pointing to the RWD as being superior, that the FWD cars are able to out brake the RWD cars?
See above. I don't know where you got that contention. If you're talking about one-on-one personal comparison to specific competititors, I suggest you let one of us drive whatever RWD car you out-braked and let's see what happens.... ;)

To make a fair comparison, compare the braking hardware, weight, and tires.

I would also need a good answer to "what's broken" and "why are we doing this" before I would support it.
Then, once again, I've wasted my time here. If I've failed to impress upon you the differences in technology, dynamics, mechanics, and driving requirements for a FWD car versus a RWD car, and you (a RWD'er and part of the voting bloc of the ITAC) don't understand the functional differences and still wonder why a FWD car needs a significant break to compete fairly (and 90 pounds doesn't cut it in ITS), then there's no point in spending further time on this discussion... :shrug:

GA

Chip42

01-19-2009, 11:57 AM

First, someone please explain why with everything mathematically pointing to the RWD as being superior, that the FWD cars are able to out brake the RWD cars? And I don't think that is just a personal opinion either.
1 - they weigh less, due the the -100/-50lb "adder" for FWD.
2 - dynamics, spring rates, and static mass are very different, usually.
3 - apex may differ slightly, especially for low speed corners, exagerating the accordian effect - watch the exits of the same corners where the FWD cars appear to be outbraking all the RWD cars...
4 - not always true, anyhow.

Until someone does come up with a 100% built ITS GSR (I'm almost there, but moving is forcing the sale of the car), it would be wasted time to argue about FWD/RWD advantages. I still personally believe that a 100% built ITS GSR at 2590lbs will be a dominating car.

Scott Seck in the CFR has a very good GSR. one of the Ira brothers does too, somewhere in the Carolinas, I think. I believe that both would agree that a built to the hilt GSR can't compete over a race length at most tracks with the RX7s and Miatas - they may get a lap, but pretty much can't get the race. just too much work for the tires over the long run. a weight break would help, but this info is available now - there's no one holding a gun to anyones head demanding that they build these cars. the club gives us a place to race with no promisses as to the competitiveness of the car as classified (though they do try)

EDIT - I just read greg's post above and wanted to add the following about FWD in braking:
most of the cars built that fit into ITA/B/C over the past 20 years or so have been FWD. this is a fact of market conditions and industry paridigm. new cars have MUCH better braking systems than older ones, and more sorted suspension geometries as well. this could go a long way to making the FWD cars look better in braking. not that the miata, as greg points out, has great brakes. it's really the only modern RWD ITA car in the same power/wt range as the good FWD cars in the class... and it often walks all over them.

Chip42

01-19-2009, 12:10 PM

It's not a fair comparison. And, I'm unaware of any valid direct same-chassis FWD v RWD platforms.

Greg - the newer Nissan Altima and Z/G-series use the same engine family and chassis core. there are a LOT of differences, but there's a start.

in the more affordable and very different chassis realm - there are the toyota AW11 MR2 (mid engine/RWD)/AE86 Corolla SR5 (front engine/RWD)/AE89 carolla FX16 (FWD) that all use the same motor (slighlty different intake on the AE86) and could be made to run the same weight and very simillar overall gear ratios. the FX16 and MR2 are very simillar in terms of frontal area, wheelbase, and Cd, and have many of the same brake and suspension components, too. very much apples to apples comparison, but good luck finding a well build FX16 for your tests...

sorry for the double post.

JeffYoung

01-19-2009, 01:30 PM

I understand theoretically why FWD has some detriment to RWD. What I am saying is I need a "why" -- a mathematical why that you keep telling us about but won't give us -- for justifying 150 lbs or more as opposed to the 100 lb break FWD cars presently get vis a vis RWD cars.

That's all. You've been asked several times to give us the formula or some math to support the 150 or more, and we're still waiting. When you are prepared to share it, I will listen.

Then, once again, I've wasted my time here. If I've failed to impress upon you the differences in technology, dynamics, mechanics, and driving requirements for a FWD car versus a RWD car, and you (a RWD'er and part of the voting bloc of the ITAC) don't understand the functional differences and still wonder why a FWD car needs a significant break to compete fairly (and 90 pounds doesn't cut it in ITS), then there's no point in spending further time on this discussion... :shrug:

GA

Greg Amy

01-19-2009, 01:59 PM

Thump, thump, thump <<<====Greg's head hitting against a wall...

Jeff, you're missing the point. Please read my stuff again, carefully.

The point is...based on my knowledge, education, and considerable FWD experience, I think the subtractors for FWD are a bit too low in ITS and ITR; to explain why I think this, I spent consierable time trying to make sure everyone understands how FWD works and why it is not directly comparable - in simple power-to-weight terms - with RWD, particularly as you increase the weights and horsepower level above general levels.

So the outstanding -- though, I agree, not explicitly-stated -- questions is, are you willing to consider increasing the FWD subtractors in ITS and ITR, possibly at the same time being supported with an easy math defense? Or is this all wasted time?

If you want a formula "justifying" my position, you got it. Just tell me where the numbers are that you'll vote "aye" for and I'll give you mathematical justification (my favorite one, of course, is "Classified weight of whatever Greg's at the time driving minus 500"... hey, it's "math", so it must be right, right?)

:shrug:

GA

I understand theoretically why FWD has some detriment to RWD. What I am saying is I need a "why" -- a mathematical why that you keep telling us about but won't give us -- for justifying 150 lbs or more as opposed to the 100 lb break FWD cars presently get vis a vis RWD cars.

That's all. You've been asked several times to give us the formula or some math to support the 150 or more, and we're still waiting. When you are prepared to share it, I will listen.

Knestis

01-19-2009, 02:11 PM

Okay, Greg - I'm really into this idea.

Let's assume, in the very broadest terms, that more mass exacerbates the issues you've described. (I think that's a fair starting point.) Make whatever other assumptions you want, and see if you can get your line to hit a couple of common examples at their current FWD-adder adjusted weight (e.g., the GolfIII in B, and the GSR in S, maybe?).

How might the math look...?

K

JeffYoung

01-19-2009, 02:15 PM

Kirk, thanks. That is exactly what I would like to see.

Greg, not trying to turn this into a Jeff Young v. Greg Amy thread, truly I'm not, and I don't think you are either.

But, this can't work this way: "accept my theory, and then I'll give you my math to back it up."

Like Kirk said, assume we agree with your theory -- because we mostly do -- and run some numbers. Show us what a non-linear subtractor would look for B cars v. A cars v. S cars v. R cars.

Kirk, question for you. If we allow this, then as a matter of theory and consistent practice, what do we do with the guy who runs similar formulas for brake performance based on swept area and weight? Do we start generating deducts for him? Or aero?

I don't disagree with Greg's theory. But I see a slippery slope here in classification rules creep that is in my view far more dangerous than removing washer bottles and passenger glass. If we end up with a 10 page classing document on how to class cars with various formulas, we are in big trouble.

Okay, Greg - I'm really into this idea.

Let's assume, in the very broadest terms, that more mass exacerbates the issues you've described. (I think that's a fair starting point.) Make whatever other assumptions you want, and see if you can get your line to hit a couple of common examples at their current FWD-adder adjusted weight (e.g., the GolfIII in B, and the GSR in S, maybe?).

How might the math look...?

K

Andy Bettencourt

01-19-2009, 02:20 PM

Greg,

You have to understand where we are coming from. You state, as fact, that it's too low. You state that we won't listen. You state that 'proving it' is basically impossible for a variety of reasons. Yet the adders are 'a bit too low'.

How the heck are we supposed to take an action item on something like this?

Greg Amy

01-19-2009, 04:01 PM

How might the math look...?
Let's take a simplistic, linear example (only an example, not a proposal!!), applicable to ITS and ITR only at this point**:

y = x-20

x = stock hp
y = subtractor

Stock hp/subtractor:
100/90
120/100
130/110
150/130
170/150
200/180
230/210

The above simplistic example takes into account some of the current norms, along with my contention that the higher in HP you go, the more "break" a FWD car needs. Using a logarithmic/exponential function would be nicer, because it's non-linear and asymptotic. The current practice of a fixed value serves only the middle, not the extremes.

**I don't recommend using the same formula for ITB and ITC because of the difference in tire sizes, and the fact that these cars rarely make enough power to "spin the wheels" (an admittedly simplistic symptom for less-available traction).

Z3_GoCar

01-19-2009, 04:34 PM

[quote=Greg Amy;281188
.... I'm unaware of any valid direct same-chassis FWD v RWD platforms.....

GA[/quote]

Have you considered the Toyota Corolla's

Fx-16 vs. the GT-S or even the 1st gen MR-2?

lateapex911

01-19-2009, 04:44 PM

My gut reaction, admittedly to the results, is that (while you state it's for ITS/R only) the lower numbers get too much of a break, (although no 120hp car is in S or R), and the higher numbers get too much of a break, yet the middle is closer to ok..
The cars in the 200 hp range are getting nearly double the break from what they currently have.

IF I were king, I'd think it could be simple, like:

ITC...no break...doesn't matter
ITB 50 off
ITA 100 off
ITS 140 "
ITR 180 "

If you want to get fancy, chose the median car in each class, assign it the number above, then adjust the adder as a percentage of it's weight. Heavier cars get a bit more help, lighter ones, a bit less.

That way, it's not just about hp. If that calc were done at the end, all other factors which play into it are accounted for.

jimmyc

01-19-2009, 04:57 PM

ekim952522000

01-19-2009, 05:05 PM

IF I were king, I'd think it could be simple, like:

ITC...no break...doesn't matter
ITB 50 off
ITA 100 off
ITS 140 "
ITR 180 "

I would say
ITC - 0
ITB - 50
ITA - 100
ITS - 150
ITR - 200

and call it good most of the rest of the process seems to use 50lb increments I see no reason to change it.

or going the more complicated route

Use adjusted PW/WT ratio for FWD cars in each class since it has the same effect that Greg is looking for but does not make the process any more complicated.

93-96 Prelude 190*1.25*10.40 = 2470
00-01 Type R 195*1.20*10.40= 2434
00-02 Celica 180*1.25*10.40 = 2340 - 50 (struts) = 2290
91-95 Legend 230*1.25*10.40 = 2990
02-03 RSX 200*1.25*10.40 = 2600 - 50 (struts) = 2550

So if you guys are aiming for about 200lbs off in ITR we could use 10.40 instead of 11.25 for ITR FWD cars.

Celica 225hp
2381 - 2290 = -91

prelude 237.5hp
2571 - 2470 = -101

Type R 234hp
2533 - 2434 = -99

RSX 250hp
2663 - 2550 = -113

Legend 287.5hp
3135 - 2990 = -145

Now one problem with lowering the weight on any of the FWD cars in ITR is I do not think the Integra, prelude, or Celica could get any lighter.

lateapex911

01-19-2009, 05:11 PM

whats interesting to me, is that some of the ITAC were not to long ago saying that the "within 100lbs of the proccess weight is fine." which could lead to 200lbs difference in class. Are now saying that 150 or 180 lbs reduction is A LOT and maybe to much?

Really? I realize that after a lot of discussion it seems that the ITAC is working on getting rid of the 100lbs difference, for many years you (the ITAC) were saying that 200lbs difference in weight wasn't a big deal....

Jimmy- It wasn't me!
-History lesson, cliff notes version. I THOUGHT the standard "go no go" was 50 pounds. In other words, when we got a request for adjustment we ran the numbers and if it was within 50, it was left alone. So, the net deviation in any class was 100. I didn't love that, but hey, you fight your battles, and all that.

Then, recently, it's become apparent that it's actually 100. Clearly, something morphed or I just was confused. I guess I thought when they said"within a hundred" I though they were talking "net".

I HATE the 100 pound "go/no go" test.

So, yea, Greg's system is talking (and I understand it's just an 'example') of taking an additional 100 pounds off cars, which i think IS a big deal. And I mean that from both perspectives. If it deserves (for whatever reason) 100 pounds off, it should get 100. but if it doesn't, it sure shouldn't get it.

I'm a guy who thinks that if we have a repeatable process, and keep good records, that when a request comes in to run the process on a car we will have three possible outcomes:

1- Run it. Result is the same as it currently sits. Document.
2- Run it. Result varies because it hasn't been through the process.
Adjust. Document.
3- Run it. Result varies from current weight, which was processed post GR, due to errors/omissions. Investigate, determine if error is current info or past, and if approriate, adjust. Document.

jimmyc

01-19-2009, 05:40 PM

So, yea, Greg's system is talking (and I understand it's just an 'example') of taking an additional 100 pounds off cars, which i think IS a big deal. And I mean that from both perspectives. If it deserves (for whatever reason) 100 pounds off, it should get 100. but if it doesn't, it sure shouldn't get it.

I completely agree. A better way to look at it, IMO, is Should it get XXXlbs weight break.

And yes i understand that it would be an addtional 100lbs, but even you were "ok" with what you thought was "0nly a total of 100lbs swing" It was thought, as i read it, to be within the "margin of error".

I believe it was Kirk, on rrax but am not 100% sure, who i remember being not worried about being "100lbs off".

In all honesty looking at the cars i know in ITS and ITR, they really couldn't even benifit for a lower minimum weight, as almost all of them struggle to make it to their current minimum weights...

There is no way your are getting a DC integra Below 2500lbs. The same goes for the RSX, prelude, and most other FWD hondas in IT.

I had read the rule book and Mike U was helpfull with letting me know what could and couldn't be removed, but until actually sitting down and looking at all the stuff you can't remove that is normal for me (honda challenge) i didn't realize what a big difference it makes.

hondaracer48

01-19-2009, 05:56 PM

There is a difference to speak of between 70% brake force on a driven axle and 70% brake force on a free rolling axle. The momentum of the flywheel raises the threshhold where the brakes would lock up. An experienced FWD driver would use this to his advantage.

hondaracer48

01-19-2009, 05:59 PM

I wouldn't mind if the GSR's weight is at 2490. I could get my GSR to 2500lbs and not have to worry about being underweight if I use too much gas on the track :)

lateapex911

01-19-2009, 07:48 PM

I completely agree. A better way to look at it, IMO, is Should it get XXXlbs weight break.

And yes i understand that it would be an addtional 100lbs, but even you were "ok" with what you thought was "0nly a total of 100lbs swing" It was thought, as i read it, to be within the "margin of error".

.

yea, in the big scheme of things, when I was fighting for much greater changes.."The Process", I was Ok with letting things sit if they were 50 off.

I understand the 'logic' of the margin of error, but....

But, if we get a "run it thru the process" request, and it came out 49 pounds off, I'd prefer to adjust it. Why? because while I freely admit...heck, I'm not ashamed so "admit" is the wrong word...I agree that our process aims to get things close, but doesn't worry about "head of pin" exactness, it does result in the weight that is as "Correct as we know".

If we allow another weight to actually rule, then we are potentially stacking errors. And if another car in the same class is the opposite, well now we have an issue...a 100 pound issue. I chose to live with that in order to get theh whole process thing online in the first place, but, I'd far prefer that we just listed the weight the process cranks out and were done with it.

I mean, when you're shooting arrows at a target, and you know you're not Olympic caliber do you say, "I suck, so I'm not going to bother aiming carefully"? To me, that's what were doing when we allow weights to be where our "as Correct as we know weight" is different.

Now that it's actually 100 plus AND minus, well, I got issues with that! LOL.

Andy Bettencourt

01-19-2009, 09:10 PM

Knestis

01-19-2009, 09:18 PM

...Kirk, question for you. If we allow this, then as a matter of theory and consistent practice, what do we do with the guy who runs similar formulas for brake performance based on swept area and weight? Do we start generating deducts for him? Or aero? ...

I'm not proposing we consider any new variables in the process (either here or in the other discussion):

** We already use "big chunk" FWD subtractors, applied objectively (Y/N) but the values were picked subjectively - I'm looking here at figuring out a way to be more granular about it.

** We already apply different "IT power factors," based on "what we know," best guesses, informal standards of engine architecture, history, etc. In the other thread, the "Nordquist Proposition" suggests that we could make those completely objective, based on physical attributes of the car. That's always been my gold standard.

I'm on record as believing that diminishing returns sets in pretty damned quickly after the factors we already worry about. That doesn't change.

K

Knestis

01-19-2009, 09:32 PM

whats interesting to me, is that some of the ITAC were not to long ago saying that the "within 100lbs of the proccess weight is fine." which could lead to 200lbs difference in class. Are now saying that 150 or 180 lbs reduction is A LOT and maybe to much? ....

To be fair, while some individual members might have said that (or something close to it), that's probably an oversimplification. And some members certainly have never believed that was the case, even if some of THEM accepted that there were organizational constraints that prevent(ed) us from dealing with it.

K

Spinnetti

01-19-2009, 09:33 PM

Geeze, such endless controversy.. why not just have a basic ruleset, then start to handicap based on actual results until the lap times fall in line for the class?

Knestis

01-19-2009, 09:36 PM

... If you want to get fancy, chose the median car in each class, assign it the number above, then adjust the adder as a percentage of it's weight. Heavier cars get a bit more help, lighter ones, a bit less.

That way, it's not just about hp. If that calc were done at the end, all other factors which play into it are accounted for.

See, that's kind of where I'm headed. Since it's ALWAYS the case in our system that higher power = more weight, we could use "weight" as the input to determine the adjuster, around some central target - much like Travis suggests for the multiplier.

OMG - we could actually have a system that yields much finer granularity, grounded on solid theory, that we didn't have to guess at.

K

Knestis

01-19-2009, 09:39 PM

Geeze, such endless controversy.. why not just have a basic ruleset, then start to handicap based on actual results until the lap times fall in line for the class?

I REALLY hope you are kidding. PLEASE tell me you're kidding.

K

Xian

01-19-2009, 09:41 PM

Geeze, such endless controversy.. why not just have a basic ruleset, then start to handicap based on actual results until the lap times fall in line for the class?

You mean handicap a chassis based on other drivers skill and prep level versus the competition? I hope that was supposed to be a tongue in cheek response...

edit:
Kirk beat me to it.

Duc

01-19-2009, 10:45 PM

00-02 Celica 180*1.25*10.40 = 2340 - 50 (struts) = 2290

Celica 225hp
2381 - 2290 = -91

Now one problem with lowering the weight on any of the FWD cars in ITR is I do not think the Integra, prelude, or Celica could get any lighter.

Lol. I am going to have a hard time of having a safe and legal car at the current weight for the Celica.

Where did the 225hp number come from the 1.25 multiplier? Best wheel hp numbers out of a NA car is 182 at the wheel (on a maintained dyno) with a 15% loss for the drive train that still only breaks 209 crank. Supercharged that motor and it makes 225.

One of the things to keep in mind is that with the more modern EFI systems (and the calibrations that go with them) the gains will be at best 10-18% with the mods allowed by the rule set. Plus the designs of the motors are also much better from the factory as the OEMs are trying to squeeze out just as much as possible. There are a very few Naturally Aspirated exceptions to this (especially when mated to a manual transmission as they derate the autos more).

What would happen to those cars that cannot make weight (aftermarket hoods, and trunks)? Do they move down to ITS? Or should the penalty go the other way as an adder for the RWD?

More food for thought.

Chip42

01-19-2009, 11:41 PM

personally - I think the adder for RWD is becoming more the place to go. in many of the classes, the slower cars couldn't get to the min weight safely (with a reasonable cage) - the newer classifications seem better about that.

that said, if we continue down this path we will all agree to unattainably low weights for the FWD cars and not have touched the "normal" RWD cars. parity can come from wither end - we should remember that.

also, as has been said a bunch (and we should all pay some attention to Derek "DUC" as he REALLY knows what he's talking about here) the newer small engines (B series honda, 2ZZ toyotas, RENESIS rotaries,...) will almost NEVER see the 20-25% power bump the IT "process" assumes. this is a serious issue that demands a rethink of the formula, as addressing the specific cars affected will lead to the above over weigt scenario, in effect a rule that cannot be followed but would possibly deliver on it's intent if it could. that's no use to anyone.

I'm currently thinking up some maths, we'll see if I can manage anything useful.

Jeremy Billiel

01-20-2009, 09:33 AM

Jeremy Billiel

01-20-2009, 09:34 AM

There is no way your are getting a DC integra Below 2500lbs. The same goes for the RSX, prelude, and most other FWD hondas in IT.

The cars can get down to about 2500 lbs. In order to meet the minimum of 2590 today the car always has to have more than a 3/8 tank of fuel when coming off the track.

jimmyc

01-20-2009, 02:52 PM

the newer small engines (B series honda, 2ZZ toyotas, RENESIS rotaries,...) will almost NEVER see the 20-25% power bump the IT "process" assumes.

I just can't believe that. I have no knowledge of any of the motors but the honda motors.

Here is what i have found, IN IT TRIM

d16a6- produces much more whp then it is rated at the flywheel from the factory

d16z6- produces about the same whp as it is rated at (flywheel) from the factory

d16y8- produces about the same whp as it is rated at (flywheel) from the factory

b18a/b- produces more whp then it is rated at (flywheel) from the factory.

b16a- produces slightly more whp then it is rated at (flywheel) from the factory.

b18c1- produces about the same whp as it is rated at (flywheel) from the factory. (the manifold here with the secondary butterflys is a hold back. Swapping to BLOX (ITR COPY) manifold gets you decent gains)

b18c5- produces about the same/slightly less whp then it is rated at (flywheel) from the factory.

H22a- produces more whp then it is rated at (flywheel) from the factory.

H23a- produces slightly more whp then it is rated at (flywheel) from the factory.

And then you get into the newer motors, were it is even more spread out.

Making a blanket statement like you made just is not correct.

Although it did always surprise me that the celica GTS ended up in ITR while the Integra GSR ended up in ITS. I remember that when the cars came out the performance numbers were around that of the GSR.

quadzjr

01-20-2009, 02:57 PM

Jimmyc.. I don't know if I missed something or you missed something.. but from what I read from Chip's post was about the percent gained from IT legal mods.. not anything to do with factory rated hp v.s. "dynoed" hp. If I am missing something, he did use the word almost.. there is always exceptions.. so think of it more as a blanket with a small hole in it! :D

dj10

01-20-2009, 03:53 PM

Since most cars can't to to the weights that are mentioned are you willing to add to weight to all the rwd cars? Another thing I didn't see mentioned was the lenght of the races we run. How much extra advantage do you need when all of the sprint races are less than 45 minutes?
I saw a RSX run 1.42.4 (Good Driver) (track record was 1.43.5) @ Mid Ohio last race of the year, sure he got dq'ed for being 19# under weight and I ran 1.43.3 with a full tank of fuel (I always try and test something at the wrong times):~). Let's wait and see some how these fwd car are develop this year and don't jump to conclusions just yet.

Duc

01-21-2009, 12:25 AM

produces much more whp then it is rated at the flywheel from the factory

They all play games with the "Advertised" hp numbers through the years. That is why the SAE produced a certifiable standard(which is better than nothing). And if they are understated then yes the 25% number "may" work. Also you can make any vehicle make high gains (Dyno queens) but how long is it going to last?

I guess my point is that with the more modern vehicles and designs come more modern systems (EFI, Exhaust, Cooling, Intake, Valvetrain). Those systems are under tighter control to squeeze out the last amount of performance, be it WHP, Fuel Economy, Emmissions, or Reliability. Think of it as a box with each one in a corner. The design of the motor is looking to hit a defined target for that market. So if you take a motor designed for Fuel Economy, Emmissions, or Reliability and slide it to the performance corner larger gains will be realized. But if you already have a system designed for performance (usually with a touch of emmissions and reliability) the gains will not be as large (10-18)%.

Many of the Celica owners have found simple ported stock headers to be a best bet on a NA motor. I find a 25% gain on a 2zz-ge to be absurd (and I am fine with that). I am sure there are other examples out there that have the same issues.

Knestis

01-21-2009, 10:15 AM

Duc describes what I *think* consideration of a displacement-specific power value should theoretically overcome (in the parallel thread).

But you know what? If nobody but me is worried about these issues, maybe I should set them free. Remember Greg A's point that we WILL eventually get "the IT that we ask for."

K

Chip42

01-21-2009, 11:34 AM

blanket statements aside - the point is that many of the (yes, often over-rated by the factory) small displacement / high output motors won't see 25% gains over factory spec. this makes the "process" broken for those examples. as ITR FWD cars started this thread, we need only focus on the 'teg Type-R and Celica GTS for relevant and known examples. these are pretty built-to-the hilt motors from the factory, and are documented to NOT see the gains presumed. RENESIS (13B evo) motors don't, either. ask anyone who WAS thinking about building an ITR RX-8.

adding weight to the RWD cars might work. it might not. as weight is really the only tool I know of available to the ITAC to try and make parity, it's the item we have chosen to discuss. Most of these discussions center around reducing weights, I was just pointing out that adding is often much more feasible. and if we look at the numbers, we MAY find that fewer rules changes would result by adding weight to some cars than subtracting it from many. particularly with the recent chanegs to the cage rules minimum wall thickness that have made a lot of existing cages heavier than they need to be now (if only by a few pounds).

and, as DUC noted, how the mfg achieved their HP ratngs varied widely until the very recent adoption of the SAE certified HP numbers. the likes of honda and toyota used to use dyno-setup calibrations and super-lightwweight oils to achieve their numbers. GM used computer models and estimates. real world numbers show that the "'das" were far OVER rated (thus the removal of the 2zz-ge from the US market) and that the GMs of the world were actually CONSERVATIVE and under rated their actual outputs. Then there is the oft-believed (though I don't have proof either way) notion that some engines (example: B16) were purposely under-rated so as not to detract from the star power of higher-end cars in the stable. obviously, the process cannot account for these variables, but they are worth noting in such a discussion.

and jimmyC - the d-series hondas, in particular the A6, are known to wake up pretty impressively under IT rules. I had no intention of including them in my "blanket". thanks for the numbers, anyhow - they are noteworthy.

Greg Amy

01-21-2009, 03:19 PM

OK, another mega-post...

My gut reaction...the lower numbers get too much of a break...the higher numbers get too much of a break, yet the middle is closer to ok...
That shouldn't be surprising, Jake; given I was offering a simplistic linear example, I intentionally used the middle as...well, the middle.

You want it to ramp faster at the bottom, the top, or both? How about another simplistic example, using exponents? This one starts fast then asymptotes up to a near flat value:

x=1.85^y

x = weight, before subtractor, in thousands
y = subtractor, in hundreds

Results in:

Weight/subtractor:
1950/100
2230/120
2390/130
2550/140
2730/150
2910/160
3110/170

...and so on.

whats interesting to me, is that some of the ITAC were not to long ago saying that the "within 100lbs of the proccess weight is fine."
I'm sincerely hoping this is being addressed adequately to zero, or at the minimum something that is truly insignificant, like 10#. Without that corrected, all of our "formulas" are just 'rearranging the deck chairs".

...cars...in ITS and ITR...really couldn't even benifit for a lower minimum weight, as almost all of them struggle to make it to their current minimum weights...There is no way your are getting a DC integra Below 2500lbs.
You'd be surprised. Dick Patullo showed us this year what's possible if you really, really try. And my (limited) experience says we've got room to...shrink?

Besides, unless the classified number is stupid low, I'd personally rather work to get a car light and end up fighting a bit heavy in a faster class, than try to fight an uphill battle with a heavier car in a slower class. Especially a FWD car.

"Not thinking it can attain that weight" is not an acceptable decision to make on the rulesmaker level. It's the same - can I call it "arrogant"? - position as stating "well, no one's ever built one, but we think it's OK". You can't say that and then from the other side state "well, we're not going to make any adjustments until you build one and prove it can/can't be done".

personally - I think the adder for RWD is becoming more the place to go.
Problem is, it'll never fly. It would mean a wholesale change to all cars in all categories, and that'll never get approved. Further, it's a different mindset: it does not address "handicapped" cars with a break, it handicaps all cars instead.

Jake Gulick: IF I were king, I'd think it could be simple, like:That's fine, but, like the example you cited above, it only addresses the middle and not the outliers. Any wonder why the CRX Si (among others) is so dominating at its "pre adjustment" weight and doesn't seem to fit the process? Simple: because of its lower horsepower it does not approach the edges of tire capability as compared to the heavier cars within ITA. Given a weight formula severely biased towards difference in horsepower (almost to an exclusion, when compared to total weight), a single-hit FWD subtractor isn't enough on such a light car to surpass the level where FWD is a detriment.

Bottom line: a one-size-fits-all approach does not work in the real world. It will always be optimized for the middle and never effectively cover the outliers. After all this, you still want to go with hard, flat, one-hit numbers for the entire class, then you must accept that it will fail at the ends of the spectrum within each class...

GA

lateapex911

01-21-2009, 03:29 PM

That's fine, but, like the example you cited above, it only addresses the middle and not the outliers. Any wonder why the CRX Si (among others) is so dominating at its "pre adjustment" weight and doesn't seem to fit the process?

GA

It's dominance might also have to do with:-
-Under rated factory hp
- it's a popular car before being classed, and it's mistakenly low initial weight leads to more folks racing it which leads to more data, which leads to more speed...

Chip42

01-21-2009, 04:09 PM

Problem is, it'll never fly. It would mean a wholesale change to all cars in all categories, and that'll never get approved. Further, it's a different mindset: it does not address "handicapped" cars with a break, it handicaps all cars instead.

not really - we have been talking about a change to "the process" and a change to the classification weight of FWD cars in the first place. why not do the same, and make it a BETTER process that nay subtract or may add weight, but with the objective of establishing parity on a relaistic weight scale?

We would obviously have to come up with a formula that is GOOD, accounts for those known outliers like the CRX you site, without harming the FWD cars with opressively high weights nor out-of-reach low weights. it would need to account for drivetrain and suspension shortcomings (struts/live axle/FWD/etc..) with something other than a fixed adder, and address the power/displacement issue so that high-strung cars are calculated with a realistic expected HP, simillarly for the cars that fit the current expectations - a set 20-25% gain is not realistic in all cases. obviously there will always be examples of cars that will blow any good formula on one side or the other, but competition adjustments OVER TIME, such as the weight added to the ITA CRX Si a few years ago, can rectify those places where it is obvious that the formula has failed us.

this won't mean, necessarily, a wholesale reweighing of the class, but I'm sure some of the established cars might gain a few, and a lot of the ITR cars would change.

my $0.02, and I'm working on developing such a formula...

ekim952522000

01-21-2009, 04:11 PM

..........

Weight/subtractor:
1950/100
2230/120
2390/130
2550/140
2730/150
2910/160
3110/170

...and so on.

...........

Greg did the idea I posted about using a modified PW/WT ratio for FWD cars in ITR of 10.45ish not fit the goal you were going for? Just curious there really has not been any comments on it.

Greg Amy

01-21-2009, 04:19 PM

Greg did the idea I posted about using a modified PW/WT ratio for FWD cars in ITR of 10.45ish not fit the goal you were going for? Just curious there really has not been any comments on it.
Sorry, didn't mean to ignore it; there were just a lot of different ideas here (I'm reading them all) and I only chose to hit the highlights.

Your idea, in effect, is to use a different multiplier for FWD cars (if you back-calc'd what you're offering to do, it's as simple as instead of taking the 1.25 standard multiplier, making it something smaller.) This idea certainly has merit; after all, my whole premise is no different, other than I'm calculating the "subtractor" afterward instead of beforehand.

The only concern I have with such an idea is that it's a fairly radical departure from current practice. knowing the history of The Great Realignment", I'm loathe to offer such large departures from the norm; I suspect that many, if not most, ITAC and CRB members are still suspicious of the whole idea(l). On the other hand, convincing them to simply twiddle around with only one of the post-calc adders/subtractors is probably a far more attainable goal.

If the ITAC would be interested in entertaining such a thought, in lieu of doing a subtractor afterwards (and thus coming to a similar, if not exact, result) I think it's worth consideration. - GA

ekim952522000

01-21-2009, 04:45 PM

Sorry, didn't mean to ignore it; there were just a lot of different ideas here (I'm reading them all) and I only chose to hit the highlights.

Your idea, in effect, is to use a different multiplier for FWD cars (if you back-calc'd what you're offering to do, it's as simple as instead of taking the 1.25 standard multiplier, making it something smaller.) This idea certainly has merit; after all, my whole premise is no different, other than I'm calculating the "subtractor" afterward instead of beforehand.

The only concern I have with such an idea is that it's a fairly radical departure from current practice. knowing the history of The Great Realignment", I'm loathe to offer such large departures from the norm; I suspect that many, if not most, ITAC and CRB members are still suspicious of the whole idea(l). On the other hand, convincing them to simply twiddle around with only one of the post-calc adders/subtractors is probably a far more attainable goal.

If the ITAC would be interested in entertaining such a thought, in lieu of doing a subtractor afterwards (and thus coming to a similar, if not exact, result) I think it's worth consideration. - GA

If we are were to do something like you suggest I think something like a modified pw/wt ratio is simplier than using a whole bunch of different subtractors, even thought they very likely would have the same result. Basically it would be like saying the power to weight ratio for FWD drives in ITR is 10.75 and 11.25 for RWD.

See below as the cars get more powerful/heavier they get more of a weight break. the 10.75 is obviously just a guess but as you can see with this example the Celica (180) would get a 113lb deduct and the acura legend (230) would get a 144lb deduct. but I guess the problem with it is that it is still linear.......:shrug:

-------X1.25- X11.25- X10.75
Stock- IT HP- RWD -FWD- DIFF
180 225 2531 2419 113
190 238 2672 2553 119
200 250 2813 2688 125
210 263 2953 2822 131
220 275 3094 2956 138
230 288 3234 3091 144
240 300 3375 3225 150
250 313 3516 3359 156
260 325 3656 3494 163
270 338 3797 3628 169
280 350 3938 3763 175

Knestis

01-21-2009, 05:46 PM

>> If the ITAC would be interested in entertaining such a thought, in lieu of doing a subtractor afterwards (and thus coming to a similar, if not exact, result) I think it's worth consideration.

I'm not quite completely out of steam on these ideas. It would help if we had a concrete suggestion for a function describing an actual curve, that provided a factor we could use in lieu of the big chunk adders. I *think* that if it accommodates the existing cases thought of as benchmarks, spitting out weights that are close enough to not cause any giant heartburn, it's got potential - simply as an exercise in selling policy.

EDIT - Mike's table might be the basis for defining just such math.

K

lateapex911

01-21-2009, 06:05 PM

ekim952522000

01-21-2009, 07:27 PM

Mike, it might be linear, but it's "self adjusting from class to class...so thats a good thing.

And, similar to choosing a "bogey weight" for the middle of the class, like 100 pounds for ITA then modifying the weight via a percentage, this does it in one step.

Here is a spread sheet were you can play around with different FWD pw/wt ratios and the difference it makes compared to RWD cars with 4 example cars on the left.

The sheet is setup for ITR with the "Bogey" being the Celica assuming a 100lb deduct for it is correct.

http://www.westcoasthc.com/FWD.xls

ekim952522000

01-22-2009, 01:01 AM

Ok I just spent about a hour running simulations through Bosch LapSim. Here are the results.

The only things I changed on the cars were FWD or RWD, HP and weight, and weight balance I used 60/40 for all the FWD tests and 50/50 for all the RWD tests.

The results are interesting.

Greg Amy

01-22-2009, 08:09 AM

Shocking results... ;)

Knestis

01-22-2009, 09:04 AM

The trends does indeed suggest that what we generally thought to be the case. At what lower HP point does it indeed seem to "not matter" anymore? I'd like to test the hypothesis that we can set this one free for low-HP cars...

K

Greg Amy

01-22-2009, 09:43 AM

At what lower HP point does it indeed seem to "not matter" anymore?
Do note that the above assumes the actual engine output; ergo, reduce the power numbers appropriately to account for IT build. In other words, where it says 150 hp above, that's generally going to mean 120 stock hp (assuming 25% power increase).

My guess? FWD no longer becomes a factor around 100-ish hp, as long as the classified weight is also small; i.e., ITC territory. And, it really starts to make a difference around 150/160-ish stock hp.

You guys don't need LapSim, you've got tGA <HEEE-UGE wink and a grin>.

GA

Andy Bettencourt

01-22-2009, 10:19 AM

Do note that the above assumes the actual engine output; ergo, reduce the power numbers appropriately to account for IT build. In other words, where it says 150 hp above, that's generally going to mean 120 stock hp (assuming 25% power increase).

My guess? FWD no longer becomes a factor around 100-ish hp, as long as the classified weight is also small; i.e., ITC territory. And, it really starts to make a difference around 150/160-ish stock hp.

You guys don't need LapSim, you've got tGA <HEEE-UGE wink and a grin>.

GA

I am sure that I am missing something but don't the numbers above show that the HP level DOESN'T matter THAT much? At 2500lbs, as you increase the hp, the delta in lap times stays pretty static...only a .3 difference when you add 50hp from 200 to 250hp?

Seems weight is the major issue. So if you had to choose, wouldn't weight be a better starting point? At least in ITS and ITR where the cars are heavy enough to have this be a factor...

Ron Earp

01-22-2009, 10:23 AM

You guys don't need LapSim, you've got tGA <HEEE-UGE wink and a grin>.

Sorry for my ignorance but what is LapSim and what is tGA?

Thanks,
Ron

JeffYoung

01-22-2009, 10:32 AM

Greg Amy

01-22-2009, 10:39 AM

I am sure that I am missing something but don't the numbers above show that the HP level DOESN'T matter THAT much?
Just to ensure you understand, the chart on the left is hp, chart of the right is weight. At 150hp (120 stock) the lap time difference (same weight) is 8/10 second per lap; at 200hp (160 stock), 1.2 seconds; at 250 hp (200), 1.6s.

Given equal 200 hp (160 stock) a 2500 pound FWD car would need a near 200# weight advantage to make equal lap times. And, this assumes a 60/40 balance; I'd *kill* to get my FWD car near that value (most are 80/20).

You don't consider that significant? I most certainly do.

But why not use weight? Keep in mind that since we set weights based on horsepower, we can only choose one variable from which to derive subtractors. It's my position that the base assumption from which everything else is derived, horsepower, should be the factor used.

That's some big numbers, Andy, and supports exactly what I've been trying to convince you of for a couple years...[/quote]

Greg Amy

01-22-2009, 10:43 AM

Sorry for my ignorance but what is LapSim and what is tGA?
LapSim is a program written by Bosch some years ago, to simulate conditions and how car changes would affect lap times. It's a pretty g-d impressive program, but it's limited by, well, being a program. But I've heard that it's good enough to where some high-level teams have re-coded it with little changes for helping to setup cars such as BTCC and such. I've personally never had the time to deal with it (though the downloads have been sitting on my computer for years....)

"tGA" is an inside joke. Years ago I was sitting on the grid at HyperFest and someone came up to me and introduced themselves, asking if I was "THE Greg Amy?" Much to my misfortune, Joe DiMinno was standing there at the time, and I've never lived it down...the Sandbox got word of it and created the "tGA" moniker. ;) - GA

Knestis

01-22-2009, 10:55 AM

How does Lapsim work? What are the inputs? Does it have a built in modifier/handicap for FWD? Why do we consider this statistical significant when the lap time differences even in the high hp range are around a second?

And why are we considering using a simulator when we are already so distrustful of dyno sheets?

I suspect we could use that same simulator, with the appropriate human inputs, to show similar detriments due to poor aero, or brakes, etc. Do we want to go there?

I trust sim software because it just does math: It has no agenda and it doesn't let perceptions skew what it tells us. I think this has potential.

And again, I'm NOT advocating - nor will I seriously consider, knowing what I currently know - using more factors than we already have on the board. NOR am I suggesting that we run every car through the simulation app...

I'm simply saying that we can hone our current model, using exactly the factors we use now, to (1) take opportunities for subjectivity out of play, and (2) get a better degree of granularity for the factors that we agree matter.

K

Knestis

01-22-2009, 10:56 AM

... My guess? FWD no longer becomes a factor around 100-ish hp, as long as the classified weight is also small; i.e., ITC territory. And, it really starts to make a difference around 150/160-ish stock hp. ...

That's about what my early morning napkin math told me, too...

Edit - and I agree that we should start with HP, since we derive weight from the same data. I completely accept that there are some inherent issues with starting with manufacturers' quoted power figures but I'm willing to trade them for consistency - except in the very special case of the rotaries.

KK

JeffYoung

01-22-2009, 11:05 AM

I understand, but sim software is written by....people. Who have perceptions and agendas.

Do we know if this program already skews results against FWD cars? Meaning, it is set up to produce the results we "expected" to see?

I trust sim software because it just does math: It has no agenda and it doesn't let perceptions skew what it tells us. I think this has potential.

And again, I'm NOT advocating - nor will I seriously consider, knowing what I currently know - using more factors than we already have on the board. NOR am I suggesting that we run every car through the simulation app...

I'm simply saying that we can hone our current model, using exactly the factors we use now, to (1) take opportunities for subjectivity out of play, and (2) get a better degree of granularity for the factors that we agree matter.

K

Greg Amy

01-22-2009, 11:11 AM

I understand, but sim software is written by....people. Who have perceptions and agendas. Do we know if this program already skews results against FWD cars?
:shrug: But, who do you trust more: us, or Bosch engineers? Who is more motivated to produce consistent repeatable, accurate, objective results?

Hey, don't let the fact that it agrees with my position cloud your judgment... ;)

Ron Earp

01-22-2009, 11:13 AM

Thanks for the explanations Greg.

I don't know anything about LapSim but I'll accept that the program is good and folks in the industry use it to setup cars.

There are engine dyno programs that are also accepted in the engine building trade and used extensively to simulate and optimize engine builds. We can purchase them and they are not very expensive. Are we willing to use these programs to predict IT horsepower gains and use that information to set weights? The program will produce data that is in line with what we expect.

I imagine we are not ready for this step.

So why are we willing to accept the output of a car simulation program to modify our IT rules set? Because it produces what we expect or want to see? What if we find another simulation program that produced results that are not inline with what we expect?

Justing playing the bastard this morning. As mentioned, I know nothing of Lapsim.

JeffYoung

01-22-2009, 11:18 AM

Bastard No. 2. here.

I just sent an e-mail to Bosch on this, as after reading the LapSim manual (which is extensive, and it seems like an amazing program), I see nothing that accounts for FWD v. RWD other than corner weights.

I am, admittedly, perplexed and amazed that we have gone from [stock hp X 1.25 X class multiplier] to doing what we are doing in this thread and in the specific output thread. I find so dangerous that I am astounded we are even discussing it.

The goal it seeks to obtain - perfect repeatability and accuracy and ultimately fairness - in IT car classing is not only unrealistic, it's impossible. and once we use Lapsim to set the FWD modifier, the next guy is going to use that program to argue why his wheel base, or his brakes, or his camshaft, or his aero, or any of the other inputs it allows justifies a modifier to his car.

THIS is the slippery slope. It sure as hell ain't washer bottles.

Greg Amy

01-22-2009, 11:30 AM

Are we willing to use these programs to predict IT horsepower gains and use that information to set weights?
I'm not suggesting that you use a program to set the FWD subtractor (though, what is an Excel formula, other than a "program"?)

And...

I see nothing that accounts for FWD v. RWD other than corner weights.
Meaning, of course, that the handicap when one does consider the drive layout will be even worse...

...I find so dangerous that I am astounded we are even discussing it....THIS is the slippery slope. It sure as hell ain't washer bottles.

Jeff (et al), remember my original contention: that the FWD subtractors being used in IT are insufficient and do not accurately reflect the handicap that FWD carries versus RWD. All of the above discussion is nothing more than supporting opinion and evidence.

Again, as I noted to Ron, I'm not asking you to take a software program's output as an article of faith, I'm simply pointing out that I'm not standing here all alone, trying to convince you of my position solely on my own experience (as vast and all-conquering it may be ;)). I'm asking for consideration to rethink how you're doing this "FWD versus RWD thing" and open your mind to the possibility that it's misguided.

You asked for formula examples, you got 'em. You asked for experienced opinion(s), you got 'em. You asked for supporting evidence, you got 'em. If you truly are interested in reasonable parity between these dissimilar platforms, and you have not descended into an easily-inferred mindset of "we can never attain it thus we shan't try", then we can move forward on the concepts. Otherwise, if all I'm going to get is gruff and heel-digging every time I adequately answer your queries, well, then we're wasting our time here... :shrug: - GA

JeffYoung

01-22-2009, 11:35 AM

Greg, I'm listening and I appreciate your efforts.

I think my structural issue with this is being lost in the focus on FWD.

ALL IT cars have advantages and disadvantages. While I could not do it as well as you, I could give you numbers to support a performance disadvantage to a particular brake setup, and then I could use LapSim to support it.

I could then do that for wheelbase.

I cold then do that for aero.

Is that where we want to go? I FULLY ACCEPT that FWD is a disadvantage. But why are we choosing to address that one versus others?

I am slowly moving back to just using stock hp and power multipliers and dump ALL of the other subjective factors because there is no rational means of sorting through which ones we should account for and which ones we shouldn't.

Greg Amy

01-22-2009, 11:38 AM

Is that where we want to go? I FULLY ACCEPT that FWD is a disadvantage. But why are we choosing to address that one versus others?
Simple: because front-wheel-drive is far more significant (versus rear-wheel drive) in terms of performance than any other factor you note. In fact, I'd suggest other than horsepower and weight, nothing else really matters if the drive layout isn't "right"... - GA

dj10

01-22-2009, 11:41 AM

"I FULLY ACCEPT that FWD is a disadvantage. "

Not necessarily in the shorter races we run.
Why are the ST FWD dominating in Grand AM?

JeffYoung

01-22-2009, 11:43 AM

That'd you need to support with numbers, and it can't be just one lap -- the FWD "disadvantage" appears to me to manifest itself over time as the tires can't handle the extra heat generated by the extra work.

I don't buy that the "FWD" disadvantage is "worse" than a 240z or yes, my car, that basically gets 3-4 laps with brakes then work and then after that it is a nightmare. I've also seen 1 second or more differences per lap due to aero differences.

And on edit, I think we need to ditch all of the adders/subtractors except torque, which makes the process work for cars like mine since it would be far too light otherwise. We should avoid this discussion on suspension type, brakes, aero, chassis, etc.

ekim952522000

01-22-2009, 12:31 PM

I think the process should be simplified as well, I think all you need is.

FWD subtractor
TQ adder

To me the whole Double wishbone adder/strut subtractor is silly because there are good and bad designs of both.

Ron Earp

01-22-2009, 12:34 PM

I don't buy that the "FWD" disadvantage is "worse" than a 240z or yes, my car, that basically gets 3-4 laps with brakes then work and then after that it is a nightmare. I've also seen 1 second or more differences per lap due to aero differences.

The difference is that you, I, or the 240Z pilot will be told

1) You aren't doing it right, you must manage your brakes or set your car up better.

2) Your brake ducts and cooling apparatus is not good enough.

3) You should have picked a different car to race. There is no guarantee of competitiveness in IT.

Now why we discuss dropping weight instead of options 1-3 when we talk about FWD cars, well, I'm not sure. I suppose because this thread is all about dropping weight and how much.

trhoppe

01-22-2009, 12:34 PM

Wait, while we're here and running LapSim, plug in some numbers from the classes right now and see where we end up in lap times :)

quadzjr

01-22-2009, 12:41 PM

I know that we have kinda got off the subject a bit about Lap Sim, but what was mentioned before.. but the human interface while working with the program can easily change the outputs. It is the same reason why many people don't trust dyno sheets (including myself). Hell just adding or removing fans in front of the car will give noticable results on the dyno.. not to mention the "human interace" with the dyno program setting it up". Ambent air temp, density, and simple water temp calibrations can make huge differences.

This discussion seems to have been very biased. Ican understand that everybody is looking out for themselves atleast a little bit. Or if you don't currently campaign a car you know your best friend drives xxx or you plan on getting into yyy and you don't want to handicap them or you. Is it possilbe to find a third party that is completely un-biased?

Greg Amy

01-22-2009, 12:48 PM

Now why we discuss dropping weight instead of options 1-3 when we talk about FWD cars, well, I'm not sure.
Taking that logic to its extreme, Ron, why should there should be ANY differential between the cars, even one based on horsepower? Set a minimum weight per class (or, hell, maybe not) and "run whatcha brung".

Hey, after all, "no guarantee of competitiveness", right...?

But we don't do that, do we? No, we don't, because we have at least a passing desire to create some semblance of parity, and we recognize that there are some macro factors, such as horsepower, that really do make a difference.

And that's my whole point: second only to ponies, the drive layout is the most important factor affecting performance in otherwise-similar cars. Yet we handle the layout as nothing more than a quickie afterthought, when in fact, it has nearly as much to do with results as does the engine...

Whatever, guys. I seem to be repeating myself, becoming redundant, over and over again, constantly saying the same things. And, maybe not so coincidentally, I seem to be doing it mostly to members of the ITAC. I've said my piece; the present members of the ITAC are either convinced or not that this is something that should be addressed. If that's "yes" then let me know and I'll be glad to work with you on it. If no, then "thanks for your input."

GA

madrabbit15

01-22-2009, 02:00 PM

Reading through this, this is all interesting stuff.

I read through all of this rather quickly but I did not see where anyone mentioned the FWD advantage. FWD powertrain losses are generally much less than that of a RWD powertrain. Powertrain loss on a FWD car may be 10-12% vs. 18 to 20% on a rwd car. Obviously varying from make to make. I think some with dyno experience with mulitple cars can give you more accurate info, this is just what I have always heard. You are changing the direction of the power and it creates more a loss, not to mention more moving parts.

I think this needs to be included in any calculations where we are looking at stock hp vs. improved hp and weight. Your thoughts?

Derek

jrvisual

01-22-2009, 02:03 PM

Bastard #3 here

tGA,
If the current subtractor is so far off how is the you currently hold at least 3 track records?

Greg Amy

01-22-2009, 02:12 PM

If the current subtractor is so far off how is the you currently hold at least 3 track records?
Because ITA is dominated by FWD cars, and the Nissan NX2000 made nearly 160 horsepower...so I held a significant advantage in horsepower.

Compare that to ITS (and to ITR, the two primary classes I'm discussing) where the FWD competitors are very much outnumbered, hold no horsepower advantage(s), and hold virtually insignificant weight advantages.

So, it should come as no surprise that when compared to other FWD cars, having a power advantage is a good thing. And, when possessing power numbers pretty much the same as your RWD competitors, FWD is a disadvantage.

Thanks for the opportunity to clarify. Next? ;)

trhoppe

01-22-2009, 02:12 PM

Bastard #3 here

tGA,
If the current subtractor is so far off how is the you currently hold at least 3 track records?
One of the dumber posts so far. Seriously? Does this even warrant an answer?

jrvisual

01-22-2009, 02:34 PM

And now that you are in a new class and new car you think you should be able to dominate just like you did with a car that had a hp advantage.

In 2008, while driving a new car you still managed 2-2nds, 1-3rd, 1-4th and 2-5ths with the 5ths being your worst finish. Sounds like a pretty good 1st year in a car that has such a huge disadvantage. How many rear wheel drive cars with their inherent advantage finished behind you in those races?

The current system works, leave it be.

Greg Amy

01-22-2009, 02:47 PM

And now that you are in a new class and new car you think you should be able to dominate just like you did with a car that had a hp advantage.
Ah, OK, I see where this is going; I apologize for thinking you had a legitimate question for me. Care to tell me who you are and why you have this "thing" for me?

BTW, you're wrong: the worst finish for me in '08 was up against the wall at Watkins Glen with a totally destroyed car, which happened while I was busting my ass trying to stay in front of two (three?) rear-wheel-drive cars that had quickly caught up to me and and were just about to pass, all while being WAAAAY in back (10 seconds or so after only 8 laps?) of yet another RWD competitor claiming to have "the same horsepower" as I did.

I'm guessing you didn't know that. And I'll have to take your word on the other results (each of which, I can only assume you are equally ignorant).

Next?

GA

Chip42

01-22-2009, 02:55 PM

Bastard #3 here

tGA,
If the current subtractor is so far off how is the you currently hold at least 3 track records?

you might remember that his biggest gripe was with ITS, ITR where HP numbers and weight are much higher, exagerating the FWD tire-killing effect.

that said - sometimes the formula as is works, and no formual can account for the amount of time, effort, and talent that "tGA" and many others have invested in their car and driving. lap times show this. they also show when simillarly well driven, prepared, and researched cars can't keep up, if only over the long haul.

as Jeff points out, FWD is not the only reason that a fast-lap car is not a race-winner, but it is one that can be observed from afar and without bias. Where things such as brakes and aero are more make/model specific, FWD adds significantly to the demand placed upon the front tires no matter what car we are specifically referring to. physics is physics.

more weight = more work for the tires
more HP = more work for the tires
cornering = more work for the tires
braking = more work for the tires
braking and cornering loads are highest on the front tires for all cars
weight tends to go to the same end as the engine, usually the front
power loads are on the driven wheels
so FWD has to place ALL of these loads on ONE set of tires
FWD also has more of the % of total weight on a single axle, the front. if you look at axle weight/hp of a FWD car vs a RWD car, it's off by 20-30%. add to that that the tires with all of that extra weight on the FWD car are doing nearly ALL of the work, where on the RWD car they share quite a bit more of the labor.

FWD easts front tires in a rate that is roughly proportional to HP and Weight. THAT is a fact. the question is what is the fair handicap to assess, and at what level?

Ron Earp

01-22-2009, 03:05 PM

But we don't do that, do we? No, we don't, because we have at least a passing desire to create some semblance of parity, and we recognize that there are some macro factors, such as horsepower, that really do make a difference.

And that's my whole point: second only to ponies, the drive layout is the most important factor affecting performance in otherwise-similar cars. Yet we handle the layout as nothing more than a quickie afterthought, when in fact, it has nearly as much to do with results as does the engine...

I do think there is a FWD disadvantage. How much of one, well, I just don't know.

I don't think FWD is, in all cases, second only to hp. What about the cars that lose braking effectiveness 1/3rd the way through the race? Not being able to stop and go into the braking zone with the other cars is a big disadvantage for some ITS cars. Just as having your tires go off and not being able to maintain cornering grip and acceleration is a potential problem with the FWD car. There are not always fixes for the braking issue, should there always be fixes for the FWD specific problem?

The brief results shown from the LapSim model assumed the FWD car had a 60/40 F/R distribution and the RWD car had a 50/50 distribution. As I'm sure you guys know, this 50/50 split deal for rear wheel drive cars is not always the case. It certainly isn't for my dinosaur. How do the predicted laptimes shake out with a 56/44 RWD car and the 60/40 FWD car?

All I know is if we starting using models with weight distrubtion and other parameters we'll be opening up the system to all sorts of requests based on specific allowances that a racer "needs" to have in order to compete. In a class that does not guarentee competitiveness.......

JeffYoung

01-22-2009, 03:15 PM

This thread summed up in a nugget. No one disputes teh FWD disadvantage. The questions are: how much? how to address it? and should we address it, and not other disadvantages?

FWD easts front tires in a rate that is roughly proportional to HP and Weight. THAT is a fact. the question is what is the fair handicap to assess, and at what level?

trhoppe

01-22-2009, 03:27 PM

This thread summed up in a nugget. No one disputes teh FWD disadvantage. The questions are: how much? how to address it? and should we address it, and not other disadvantages?

We should almost start a new thread with the two posts above and go from there.

jrvisual

01-22-2009, 03:41 PM

The questions are: how much? how to address it? and should we address it, and not other disadvantages?

Yes we should address and we have. I am just not convinced that the 100# is not enough. Fwd is a disadvantage and it has been address.

Every car has it's advantages and disadvantages. My car once complete will never make weight. That is a disadvantage. Should I be able to remove my heater core and washer bottle? Absolutely, but not until everyone is allowed to do so.:D

If we get to complex with how you go about determining weights, we will open it up for all kinds of other valid arguments for why some other car should be lighter. Prove to me that 100# is not enough and I will support it. But making that point based on some software is a dangerous road.

And Greg, I have nothing against you. I was just using you as the original poster to argue my point. I did see the DNF result for WG, sorry to here about your car and I am glad you are ok.

JeffYoung

01-22-2009, 04:09 PM

Jeff R. (above) is new to IT, just learning and local to Ron and I. He's building a RWD ITS car that is going to have a LOT of inherent disadvantages (I just noticed the 50/50 weight distribution that Ron pointed out -- that's just not true of a large portion of RWD cars).

I suspect he sees a push to reduce the weight of a competitor car -- the GSR -- that all of us have seen run at or close to the front. Give him some time to learn about our disdain for on track results, etc. -- but also understand how some of this looks to a newcomer.

Yes we should address and we have. I am just not convinced that the 100# is not enough. Fwd is a disadvantage and it has been address.

Every car has it's advantages and disadvantages. My car once complete will never make weight. That is a disadvantage. Should I be able to remove my heater core and washer bottle? Absolutely, but not until everyone is allowed to do so.:D

If we get to complex with how you go about determining weights, we will open it up for all kinds of other valid arguments for why some other car should be lighter. Prove to me that 100# is not enough and I will support it. But making that point based on some software is a dangerous road.

And Greg, I have nothing against you. I was just using you as the original poster to argue my point. I did see the DNF result for WG, sorry to here about your car and I am glad you are ok.

jimmyc

01-22-2009, 04:32 PM

On track performance shouldn't be looked at like Jeff R. is.

Maybe ITS is not really that competitive in the NE? Maybe Greg is some super hero driver that is secertly an F1 friday test driver? Maybe the 9/10th build on the GSR he drivers is leaps and bounds more then anything else in the ITS feild.

In the SFR we used to have a few ITA cars that would almost always out qualify the entire ITS feild.

ekim952522000

01-22-2009, 04:40 PM

ok I will be running a few more simulations tonight probably with a 55/45 weight for RWD cars and 70/30 for FWD.

But let me explain where I was going with it I do not think it can give us how much we need to reduce the weight but it does show the trend that the more powerful a car gets the bigger the gap opens up when comparing FWD and RWD.

Let's say that the FWD subtractor for ITA is correct. What that means then is that why'll it is possible that the subtractor for ITS is correct, it is not likely that the subtractor is correct for ITR, ITB, or ITC.

Can we all agree on one thing from the numbers presented in the simulation that it is very likely that at a minumun each class should have it's own subtractor for FWD.

Example:
ITR - 150
ITS - 100
ITA - 50
ITB - 25
ITC - 0

Doesn't the above make more logical sense then having ITA - ITC the same and ITR, and ITS the same given the above simulation results?

Ron Earp

01-22-2009, 04:44 PM

ITR - 150
ITS - 100
ITA - 50
ITB - 25
ITC - 0

Doesn't the above make more logical sense then having ITA - ITC the same and ITR, and ITS the same given the above simulation results?

Yes, off the cuff it does make sense that as the weight and power go up then the modifier would also slightly increase.

But is this in addition to the weight break the cars already got when classed?

jrvisual

01-22-2009, 04:47 PM

JeffYoung

01-22-2009, 04:50 PM

My brakes are worse than a GSR's. Run them through LapSim (swept area, rotor size, etc. -- see if it even has "drum size") and post up the differences.

ekim952522000

01-22-2009, 04:57 PM

Yes, off the cuff it does make sense that as the weight and power go up then the modifier would also slightly increase.

But is this in addition to the weight break the cars already got when classed?

I am not quite understanding Ron what I was presenting in that quickly thrown together example would be the total FWD subtractor applied to the car.

I don't really care what the exact numbers are right now.

I would just like us all to agree that as you go up to a faster class a lager subtractor should be used. we can work out what that subtractor should be next.

ekim952522000

01-22-2009, 04:59 PM

My brakes are worse than a GSR's. Run them through LapSim (swept area, rotor size, etc. -- see if it even has "drum size") and post up the differences.

I think this would show a similar result to the FWD result. BUT Brakes sizes are all over the place and could make for a very complex formula. FWD is a simple yes or no question.

EDIT: Are you suggesting that FWD cars don't need a subtractor to be competitive?

Ron Earp

01-22-2009, 05:01 PM

My brakes are worse than a GSR's. Run them through LapSim (swept area, rotor size, etc. -- see if it even has "drum size") and post up the differences.

Don't forget, you've got a rear axle that allows for no camber gain and is a hell of a lot of weight. You have to apply all your power through the rear tires that are never optimized for grip due to the fixed geometry. Make sure that counts in the sim.

I've got a poor front suspension compared to a GSR. My brakes are far worse than a GSR. Drums? No I doubt it has that as a choice. Plus I bet the LapSim doesn't have an option for solid discs. It probably only has vented disc rotors.

Jeremy Billiel

01-22-2009, 05:02 PM

You guys are seriously funny. No seriously....

This is not about Greg, this is about FWD disadvantages.

Why did Greg do "ok" this year?

1. He has above average driving abilities.
2. We put a boat load of money, testing and time into the car to get it where it is.
3. The NER ITS car counts were not there this year. If we went to the ARRC it would be very easy to see how far back we would have been.

I can tell you that since I built this car it has always and will continue to have the same FWD problem that others are experiencing in ITS. The other reason that this has not been talked about previous is simple....

THERE ARE ALMOST NO ITS or ITR FWD cars running out there! Is that in indicator of something?

esuvee

01-22-2009, 05:05 PM

The big problem I see with the LapSim results is that no changes were made beyond FWD/RWD and weight bias. I went through and 'optimized' each setup's spring and bar rates for a FWD and RWD ITR 944 and for a FWD and RWD ITA CRX. I found 112lbs needed to equalize the CRX and 250lbs needed with the 944 after working all configs to their optimal spring/bar setup. Both 'fake' setups (RWD CRX and FWD 944) took multiple iterations of roll moment distribution changes to get the best lap time and both gained more than 1 second. I'm still not sure the setups are perfect.

Imagine if you just put a RWD drivetrain in my CRX and left springs and bars alone :eek:

So, 112 and 250 are pretty different numbers, I am in the camp that this is HP related. LapSim allows you to watch the driver inputs including throttle pos. The FWD 944 spends a lot more time at part throttle than either the RWD 944 or the FWD CRX. I am also in the camp that FWD cars like mine are stupid and should be avoided at all costs so I favor no further weight brakes:) My next racecar will drive the right end of the car.

I also favor rules stability. We're getting close to a nice setup here, again, what specific problem do we think we have? In ITR most 'it weighs too much' complaints are already headed to the RWD rather than the FWD cars.

Alex

ekim952522000

01-22-2009, 05:16 PM

Greg Amy

01-22-2009, 05:18 PM

Had Greg finish on the podium every race this year, this thread would not even exist.

Jeff Roussel, not so surprisingly there's more info you don't know.

Like, for example, in '06 (?) when I was racing the NX (getting all those track records, remember?) and the "subtractor" for ITS was only 50# (and I really didn't give two shakes about the GS-R or ITS). I made it pretty clear back then that I thought it wasn't enough and needed to be bumped to 150#, if not 200#, instead of 50#. And I've got the emails to prove that position.

Cut to late '07. The "subtractor" was now 100# for ITS, my buddy was racing a GS-R in ITS and I was still in ITA (and I still didn't give two shakes about ITS) and I told my buddy it still wasn't enough, that it needed to be 150# if not 200#. And I have the emails to prove it.

Cut to 2008. I'm bored with the NX and am thinking about sitting back for a little while. Instead I agree to run with my buddy in the GS-R in ITS; I tell him, however, that the numbers still aren't right, but we can go have fun. I get into yet another email exchange with ITAC member(s) telling them it's not enough (and I kept those emails to prove it); their response was, in effect, "look, just go try it and let's see what happens". And, not so surprisingly, nothing happened to change my position. It was at that point I pretty said we weren't going to put any more development in this car.

Then I wrecked the car in September and I pretty let it be known I had no interest in pursuing it further (don't believe me? Ask my Jeremy how he had to talk me into building another car with him).

Bottom line: I know what I'm talking about. I've picked and prepped numerous winning cars over the last nearly 20 years of racing. I'm rarely wrong on my predictions of performance of vehicles.

Jeff R, I give newcomers a lot of slack, and I understand how the Internet keyboards tend to make heroes out of people. But I would sincerely appreciate it if you would desist trying to imply that there's selfish motivation behind this. I'm not asking you to believe me, I'm simply asking that you cut. it. out. In return I promise to overlook your glaring deficiencies in experience, simultaneously overlooking that you have a massive, and potentially ignorant, conflict of interest coupled to your position as well.

Capiche?

GA

Ron Earp

01-22-2009, 05:28 PM

Yes you are correct I did not change all those variables but I was trying change as few variables as possible. Again I will repeat my self I am not suggesting we use the weights that Lapsim generates. BUT we can agree that it shows a trend of more power = larger gap from FWD to RWD right?

Just for sake of interest what are the hp ratings of the theoretical CRX and 944?

lateapex911

01-22-2009, 05:29 PM

But everybody looks at on track performance. Had Greg finish on the podium every race this year, this thread would not even exist.

LOL, you don't know the Greg Amy!

What's funny about this is that, for those with long term experience (10 years lets say) in IT, this issue was far far down the list of "issues" just a few years ago.

But, we're racers, and if you are a racer, you better be thinking about ways to improve things, and you'd better be thinking in creative ways.

So, we apply that mindset to the classing of our cars.

IT is MILES ahead of where it used to be. great.

But...it could be better. Of course, we need to tread carefully not to dink up the success we've had.

I think that there is merit and logic in examining a "sliding scale" of adders for FWD. I have no problem with the adder concept for FWD, I think it's certainly needed, but i'm not sure if we apply in the best manner currently.

I'd suggest that, if you all feel strongly about this, that you let the ITAC know. Write a proposal. Add some objective documentation that you feel supports your case. (Clearly, "I had to work my ass off to stay in front of RWD cars" won't cut it there!) And if you like, detail a method to accomodate your proposal.

Personally, I like the concept of choosing a "bogey weight" per class then deviating from that via percantages for heavier or lighter cars. Or if we could work that into the class factor number and it essentially yeilded the same result, that would be cool to.

I've always known the "fine tuning" of the process would be an ongoing project, but everyone needs to be aware of the history, and the big picture.

lateapex911

01-22-2009, 05:32 PM

And Greg?? C'mon, be nice...take the high road. ;)

JeffYoung

01-22-2009, 05:50 PM

Jeremy, honestly, I think it is an indicator that ITS at least has been a Mazda/Datsun/BMW class. Those cars have been around a long time and are all fully developed and sorted.

I frankly know of several GSRs that run in ITS -- Ivan's (RIP), Scott Seck's (FAST), Cliff Ira (Fast), the two from DC Region that come down to run enduros at VIR (one ran a 2:16 by the way, which I think was the fastest ITS lap of that race), Zsolt's and yours.

So, that's six on the east coast alone, for a car that is still fairly new to ITS in the grand scheme of things.

On your car, sphericals? what shocks? crank scraper? Motec? done testing to find the best place to pick up intake air? worked hard to make the rear brakes do as much work as possible? worked on conserving tires over the course of a 30 minute race? run Hoosiers? etc. etc. etc......

We aren't talking about Greg, or at least most of us are trying not to.

Eric, I agree FWD is a disadvantage. I'm just not sure why we are picking THIS disadvantage out for special treatment, although I understand Greg's position that other than power/weight FWD is one of the most if not the most significant performance factors.

You guys are seriously funny. No seriously....

This is not about Greg, this is about FWD disadvantages.

Why did Greg do "ok" this year?

1. He has above average driving abilities.
2. We put a boat load of money, testing and time into the car to get it where it is.
3. The NER ITS car counts were not there this year. If we went to the ARRC it would be very easy to see how far back we would have been.

I can tell you that since I built this car it has always and will continue to have the same FWD problem that others are experiencing in ITS. The other reason that this has not been talked about previous is simple....

THERE ARE ALMOST NO ITS or ITR FWD cars running out there! Is that in indicator of something?

Jeremy Billiel

01-22-2009, 06:03 PM

Jeremy, honestly, I think it is an indicator that ITS at least has been a Mazda/Datsun/BMW class. Those cars have been around a long time and are all fully developed and sorted.

I frankly know of several GSRs that run in ITS -- Ivan's (RIP), Scott Seck's (FAST), Cliff Ira (Fast), the two from DC Region that come down to run enduros at VIR (one ran a 2:16 by the way, which I think was the fastest ITS lap of that race), Zsolt's and yours.

So, that's six on the east coast alone, for a car that is still fairly new to ITS in the grand scheme of things.

On your car, sphericals? what shocks? crank scraper? Motec? done testing to find the best place to pick up intake air? worked hard to make the rear brakes do as much work as possible? worked on conserving tires over the course of a 30 minute race? run Hoosiers? etc. etc. etc......

We aren't talking about Greg, or at least most of us are trying not to.

Eric, I agree FWD is a disadvantage. I'm just not sure why we are picking THIS disadvantage out for special treatment, although I understand Greg's position that other than power/weight FWD is one of the most if not the most significant performance factors.

Jeff - All us Integra GSR guys talk and we, like them, have all the best stuff. Is there perhaps some stones we need to turn sure, but for me to list the mods will do nothing to this argument.

This argument is SIMPLE. In fast, high HP FWD cars, the front tires are asked to do too much and thus additional weight should come off.

JeffYoung

01-22-2009, 06:07 PM

I won't dispute any of that except for "and thus the additional weight should come off."

Do you agree that your brakes are better than mine? And thus the additional weight should be taken off.

Do you agree that your suspension is better than mine? Remember, you are putting power to ground through an adjustable, independent suspension. I'm trying to do so via a heavy, unsprung live rear axle with no camber adjustment. That stick axle is being asked to do too much and doesn't allow me to take advantageo f the torque and power that led to my car being classed at the weight it is.

Your car is far newer and has a much cleaner aero profile. And thus the additional weight should be taken off.

etc. etc. etc.

Jeff - All us Integra GSR guys talk and we, like them, have all the best stuff. Is there perhaps some stones we need to turn sure, but for me to list the mods will do nothing to this argument.

This argument is SIMPLE. In fast, high HP FWD cars, the front tires are asked to do too much and thus additional weight should come off.

Jeremy Billiel

01-22-2009, 06:21 PM

I won't dispute any of that except for "and thus the additional weight should come off."

Do you agree that your brakes are better than mine? And thus the additional weight should be taken off.

Do you agree that your suspension is better than mine? Remember, you are putting power to ground through an adjustable, independent suspension. I'm trying to do so via a heavy, unsprung live rear axle with no camber adjustment. That stick axle is being asked to do too much and doesn't allow me to take advantageo f the torque and power that led to my car being classed at the weight it is.

Your car is far newer and has a much cleaner aero profile. And thus the additional weight should be taken off.

etc. etc. etc.

We were on the same page and then you brought your pensonal car into this. You have the EXACT same car except one is FWD and one is RWD. By having the same everything else the ONLY difference is RWD. With that said, the question is how much of a benefit should that FWD car get based on its disadvantages that have already been discussed? Currently its #100 lbs. I happen to think its too little.

THAT is the argument. Do not bring cars into the mix. It can be any car...

JeffYoung

01-22-2009, 06:29 PM

Jeremy, there are significant differences between your car and mine. Vented rotors v. solid, rear discs v. drums, live rear axle with which I am trying to power down v. independent suspension on drive wheels (probably the biggest advantage you have but I digress), aero, etc.

I'm bringing up "my car" because that is easy thing to do and what everyone is GOING to do (although they will couch it in general terms) if we do/allow this.

I'd rather we let all cars suffer their own disadvantages. Class at power to weight, deal with torque and move on.

Andy Bettencourt

01-22-2009, 06:30 PM

Can anyone with a decent IT effort post their actual weight distributions? I stopped at the shop today and grabbed the sheets for my Miata and wasn't too surprised to see a 53-47% distribution from an alignment session (with the amount of gas I would have when I crossed the scales post race)

I am guessing that the Miata is one of the better RWD cars in terms of % so I wonder if we could see the Teg's numbers to insert into the SIM. Maybe 60/40 and 55/45 are better representive of real weights, especially with what clever guys are doing with cages and rear 'sway bars'...

It's also possible that real racing weight % for FWD's should be more like 65/35....but I would love to see the numbers. I have a feeling that with the engineering you can do within the rules, the difference may be smaller than was used in the SIM. Maybe not.

Given the information I have seen so far, I could definately support ekim's:

ITR - 150
ITS - 100
ITA - 50
ITB - 25
ITC - 0

Understanding this is all a 'guess', I would just like to make the 'least stupid' guess! :)

JeffYoung

01-22-2009, 06:40 PM

Ron has cross weights on the Z car somewhere.

dj10

01-22-2009, 07:12 PM

[quote=Andy Bettencourt;281556]Can anyone with a decent IT effort post their actual weight distributions?

51/49

Gary L

01-22-2009, 07:38 PM

Can anyone with a decent IT effort post their actual weight distributions?
At "perfect" race finishing weight of 2640 and matched cross weights - front 51.0, rear 49.0 on my ITB Volvo.

Xian

01-22-2009, 07:39 PM

My CRX was 61.3/38.7 at 2258#'s (spec weight is 2250). I don't have figures yet for the Civic.

FWIW, I think the sliding scale would be the easiest to implement and the least "dangerous" option I've seen (short of doing nothing which has it's own dangers).

Christian

edit:
Crossweights were 51.5:48.5

Jeremy Billiel

01-22-2009, 08:26 PM

OK here are the stats for the ITS Integra

Front 63.8%/Rear 36.2%

Cross Weight 50/50

Total Weight 2598 (8 lbs over)

Jeremy Billiel

01-22-2009, 08:36 PM

Mike - Re-run those LapSim numbers at 65/35 to see how quickly that gap gets worst. I bet its not linear.

Ron Earp

01-22-2009, 08:45 PM

260Z:

52.5 / 47.5 as of last year with me and about 5/8 of fuel. Has a bit of a nasty wedge though.

I think we can improve the weight dist this year because I've lost some weight off the car and will be moving some items about.

esuvee

01-22-2009, 09:20 PM

Just for sake of interest what are the hp ratings of the theoretical CRX and 944?

I used 130 for the CRX and 225 for the 944. The shapes of the curves are obviously different as well. It's a couple of cars I have a bit of info on and already had models for.

Alex

Andy Bettencourt

01-22-2009, 09:24 PM

ekim952522000

01-22-2009, 09:31 PM

Ron Earp

01-22-2009, 09:51 PM

I used 130 for the CRX and 225 for the 944. The shapes of the curves are obviously different as well. It's a couple of cars I have a bit of info on and already had models for.

Alex

130 and 225??!

I think you have the 944 a over rated and the CRX under rated. There isn't a 100hp difference between these cars in IT trim.

Besides, we're talking about S cars and they will have similar hp levels. With Greg's ITS Integra and a good ITS build on brand X we're probably only talking about a 15hp difference if that. Greg and his boys don't build crap so I'm sure it has beans.

My 260Z makes about 168 rear wheel hp and some is on the table. I bet we can get it to hit 175 rear wheel hp at least, or about the same or more than a good 240Zs. I'd say I'm a committed IT racer who crosses ts and dots is on the engine. Isn't a well done Integra around 170 to 175 whp? I remember Ira telling me his was somewhere in the ballpark and it was knocking down some 2:16s at VIR, so he has some juice.

Ron

dj10

01-22-2009, 10:02 PM

How about the Egg? Looking at some of the RWD'ers, I would say using 50-50 is fine. Cross weights are not relevent to the discussion - correct? Everyone should be able to achieve 50-50 cross weights - even though its not neccessarily the best thing.

AB, looks like those front drivers are going pretty well @ Daytona. How do they do it? There races are a lot longer than our's are.

Good job on qualifying btw, I'll be rooting for you......good luck tomorrow. Damn, I wished I was down there!:cool:

Andy Bettencourt

01-22-2009, 10:06 PM

130 and 225??!

I think you have the 944 a over rated and the CRX under rated. There isn't a 100hp difference between these cars in IT trim.

Besides, we're talking about S cars and they will have similar hp levels. With Greg's ITS Integra and a good ITS build on brand X we're probably only talking about a 15hp difference if that. Greg and his boys don't build crap so I'm sure it has beans.

My 260Z makes about 168 rear wheel hp and some is on the table. I bet we can get it to hit 175 rear wheel hp at least, or about the same or more than a good 240Zs. I'd say I'm a committed IT racer who crosses ts and dots is on the engine. Isn't a well done Integra around 170 to 175 whp? I remember Ira telling me his was somewhere in the ballpark and it was knocking down some 2:16s at VIR, so he has some juice.

Ron

Jeremy and Greg can give the details but I think they ran this year with just bolt-ons and an ECU. I think they wanted to do the suspension and then evaluate. Seems as if another thread had that car at around 180whp with all the balls and whistles. Probably 128-130ft/lbs of wheel toque max though.

The TYPE of 944 has to be defined...a regular 944 8V should be about 152whp. The CRX is about 130whp.

esuvee

01-22-2009, 10:13 PM

130 and 225??!

I think you have the 944 a over rated and the CRX under rated. There isn't a 100hp difference between these cars in IT trim.

Besides, we're talking about S cars and they will have similar hp levels. With Greg's ITS Integra and a good ITS build on brand X we're probably only talking about a 15hp difference if that. Greg and his boys don't build crap so I'm sure it has beans.

My 260Z makes about 168 rear wheel hp and some is on the table. I bet we can get it to hit 175 rear wheel hp at least, or about the same or more than a good 240Zs. I'd say I'm a committed IT racer who crosses ts and dots is on the engine. Isn't a well done Integra around 170 to 175 whp? I remember Ira telling me his was somewhere in the ballpark and it was knocking down some 2:16s at VIR, so he has some juice.

Ron

Well, I'm pretty sure on the CRX so we'll have to agree to disagree on that one and I mentioned I was talking about an ITR 944.

Alex

Ron Earp

01-22-2009, 10:14 PM

Jeremy and Greg can give the details but I think they ran this year with just bolt-ons and an ECU. I think they wanted to do the suspension and then evaluate. Seems as if another thread had that car at around 180whp with all the balls and whistles. Probably 128-130ft/lbs of wheel toque max though.

So what we're talking about are S cars here and there isn't going to be any difference in hp for this comparison. Torque, yes, but hell I'm only 160 ft/lb versus say 130 ft/lb with the Integra. A difference for sure. Torque is better, helps hide my lack of driving skillz.

Anyhow, hp wise a good S car is going to be around 175-180 whp FWD or RWD.

Ron Earp

01-22-2009, 10:15 PM

Well, I'm pretty sure on the CRX so we'll have to agree to disagree on that one and I mentioned I was talking about an ITR 944.

Alex

There aren't any 944s in ITR.

We're not trying to balance ITR cars with ITA cars. I was thinking we were looking at ITS cars here.

Knestis

01-22-2009, 10:21 PM

...I could then do that for wheelbase.

I cold then do that for aero.

Is that where we want to go? I FULLY ACCEPT that FWD is a disadvantage. But why are we choosing to address that one versus others?

...

Is that where we want to go? How many times is it necessary to say no? No. NO. No means no.

Why? Because that's what we've chosen to do for a long time.

K

Andy Bettencourt

01-22-2009, 10:22 PM

Try these cars:

Crank hp: 212

One rear wheel, one front wheel.

Then this one:

Crank hp: 255

One rear, one front.

Knestis

01-22-2009, 10:23 PM

"I FULLY ACCEPT that FWD is a disadvantage. "

Not necessarily in the shorter races we run.
Why are the ST FWD dominating in Grand AM?

Because they make up their weights reactively, in an effort to "get it right." They wobble back and forth between advantages, season by season.

K

Andy Bettencourt

01-22-2009, 10:24 PM

Is that where we want to go? How many times is it necessary to say no? No. NO. No means no.

Why? Because that's what we've chosen to do for a long time.

K

And while this is hard, I think this is more do-able than trying to quantify wheelbase or aero...fo-sho!

Andy Bettencourt

01-22-2009, 10:25 PM

Because they make up their weights reactively, in an effort to "get it right." They wobble back and forth between advantages, season by season.

K

And they do NOT have the same prep rules. Each car has it's own mini spec line. Daytona is a GREAT HP track...

esuvee

01-22-2009, 10:25 PM

OK I am getting ready to do some more simulations looks like I am goiong to go with RWD 50/50 - FWD 65/35 2500lbs 100-300 IT HP

Only variables will be FWD/RWD power and Weight balance. I will will see how much weight you have to take off each FWD model to make the lap time equal. Should have some interesting results.

I still think that even if you don't intend this data to be used you are putting it out there and it will influence the discussion. Especially since you are now calculating actual weight differences that people will begin to quote.

Whatever time delta you see will be wide or narrow by ~1 second due to setup problems on one car or the other, this translates into 50's to 100's of pounds that you are guaranteed to be off.

My already optimized RWD 944 converted to FWD with no changes was running 2:04.3 around the MRC. After revising springs, bars and brake bias for the FWD config it ran a 2:03.48 which narrowed the amount that needed to be made up with weight by ~1sec.

Again, imagine throwing a FWD drivetrain in a 944 and making no suspension changes! You are figuring out how much weight would need to be removed from this bastard car to make it as fast as a good RWD 944, it's going to be a much bigger number than makes any sense to the real world.

Alex

JeffYoung

01-22-2009, 10:26 PM

esuvee

01-22-2009, 10:32 PM

There aren't any 944s in ITR.

We're not trying to balance ITR cars with ITA cars. I was thinking we were looking at ITS cars here.

No ITR 944S2 on pg 344? I must have written my own GCR then.

I was following the discussion about weight and HP and their effect on differences in laptimes of FWD and RWD cars across all IT classes. I also had two convenient models already on my machine.

Alex

Knestis

01-22-2009, 10:33 PM

But everybody looks at on track performance. Had Greg finish on the podium every race this year, this thread would not even exist. Is it a good gauge? NO. Should it be used to make adjustment to rules? NOT in IT.

With respect, you don't actually know of what you speak. This topic is in the top five, I think, right now in the IT rulez biz.

K

ekim952522000

01-22-2009, 10:45 PM

It's a different question this time Kirk.

Why is torque more important of an issue to address than others? Meaning, why do we say yes to one and no to the others.

Jeff has given me a plausible explanation, but I still don't have any real numbers to back it up. But I am still concerned by the groupthink that we need to address torque because it is a advantage and not other just as easily provable advantages.

I'm rapidly coming to the conclusion that the best result, for me, for logical consistency is to vote (and it's just one vote) to simplify the process to power and weight, with a FWD modifier.

Bold = changed by me

Jeff do you see how the same argument can be made for not factoring in torque that you are using for not factoring in FWD? How is a Torque adder any different than a FWD subtractor?

Andy Bettencourt

01-22-2009, 10:49 PM

Bold = changed by me

Jeff do you see how the same argument can be made for not factoring in torque that you are using for not factoring in FWD? How is a Torque adder any different than a FWD subtractor?

We DO add for torque in some cases. 100lbs right onto the min weight to those V8's in the proposal. What we don't do is have a formulamatic part of the equation for it.

Knestis

01-22-2009, 10:52 PM

It's a different question this time Kirk.

Why is FWD more important of an issue to address than others? Meaning, why do we say yes to one and no to the others.

Greg has given me a plausible explanation, but I still don't have any real numbers to back it up. But I am still concerned by the groupthink that we need to address FWD because it is a disadvantage and not other just as easily provable disadvantages.

I'm rapidly coming to the conclusion that the best result, for me, for logical consistency is to vote (and it's just one vote) to simplify the process to power and weight, with a torque modifier.

To this point, we've collectively (the ITAC) thought it mattered enough as a variable influencing performance, that we could include it WITHOUT lots of headache. Good upside, low downside.

In reality, what we think of as "front wheel drive" is probably a composite variable that includes the influences of both FWD and weight distribution, since they go hand in hand. And lower driveline losses might play a role, albeit probably the other direction.

Now, I agree with your basic premise for low power/lightweight cars. The idea of giving otherwise equal cars (say the Corolla FX16 GTS vs. the RWD Corolla GTS) a break ONLY because it's a front-driver seems qualitatively silly.

BUT THAT'S WHAT WE'RE TRYING TO AVOID: Making judgments by our guts, pulling numbers out of our butts. That said, I'd endorse your idea of doing away with variables if that's what it took to get consensus around a repeatable, transparent process that considers physical attributes of the car and doesn't allow for butt-number-pulling.

K

ekim952522000

01-22-2009, 10:52 PM

I still think that even if you don't intend this data to be used you are putting it out there and it will influence the discussion. Especially since you are now calculating actual weight differences that people will begin to quote.

Whatever time delta you see will be wide or narrow by ~1 second due to setup problems on one car or the other, this translates into 50's to 100's of pounds that you are guaranteed to be off.

My already optimized RWD 944 converted to FWD with no changes was running 2:04.3 around the MRC. After revising springs, bars and brake bias for the FWD config it ran a 2:03.48 which narrowed the amount that needed to be made up with weight by ~1sec.

Again, imagine throwing a FWD drivetrain in a 944 and making no suspension changes! You are figuring out how much weight would need to be removed from this bastard car to make it as fast as a good RWD 944, it's going to be a much bigger number than makes any sense to the real world.

Alex

I agree 100% that the numbers will be too big for any real world use what I am looking to see is if the relationship for removing the weight to make the times equal is linear or not, that is all. If it takes 350lbs to match up the time I am not going to suggest that 350lbs should be taken off a ITS prelude. I also openly admit that there is flaws in the system I am using BUT as of right now it is the best method I have for doing repeatable controlled tests to try and see a pattern.

ekim952522000

01-22-2009, 10:58 PM

We DO add for torque in some cases. 100lbs right onto the min weight to those V8's in the proposal. What we don't do is have a formulamatic part of the equation for it.

Correct and (correct me if I am wrong) some cars recieve a 50lb add and some a 100lb add. This is the same thing we are talking about doing for FWD cars here. If it is a low powered FWD car it gets - 50 a very high powered FWD car -100. A really high powered one -150.

Is there a difference?

<----Mke who is very impressed that this conversation is remaining so on topic and focused, It does show how many people care about the category and that's a good thing no matter which side of the FWD line your on.:)

JeffYoung

01-22-2009, 11:03 PM

Fair question/point.

For me, torque is a part of the power/weight process that is missed and must be accounted for to complete the one basic calculation we have to perform.

Plus, my car gets a torque adder, and it has to in order to account for its oddball motor. I simply think it fair we leave the torque modifier in to account for odd low hp/high torque motors like mine, the GM 3.8s, the AMC 4.2s (and yes there is at least one running in ITA, the 325e (a potential class killer in ITA) and the V8s in ITR.

I also agree this has been a great, mostly civil discussion. Appreciated all around.

Bold = changed by me

Jeff do you see how the same argument can be made for not factoring in torque that you are using for not factoring in FWD? How is a Torque adder any different than a FWD subtractor?

Chip42

01-22-2009, 11:05 PM

Jeff - you know the process better than me, but doesn't your car get a stick axle adder, a drum brake adder, and a strut adder (all negative) and a torque adder (positive), too?

torque is an advantage. yes, when misused it can roast the tires and/or cause dents. when used well, it helps win races. it deserves an adder.

the rest are disadvantages - they deserve the negatives weights. as does FWD. are those adders adequate? I don't know. throw the argument out there. these are all characteristics that, like FWD, can be simplified to "yes" or "no" without going into make/model. FWIW, I think that solid disks deserves a negative adder, too, if it is not in play.

Also (not related to anything in "the shape of things that break") we have to stay focused on the reality of the fact that the weights of (mostly) the smaller (higher specific output) cars being classified (ITR in particular) are often impossibly light (or unwisely light given the 1.5+ ton "tanks" on course and the safety skimping that will undoubtedly accompany a full-on lightweight build). Newer cars weigh a lot. why make a rule that no one can use?

how about a new Power/weight multiplier, at least in ITR (less established, less people to upset) that might allow for the adders to take effect (in real cars, not on paper) and THEN see if they are adequate. until they are achievable, there's little sense in arguing about it.

JeffYoung

01-22-2009, 11:09 PM

Chip, not at all. I get no deductions for live rear, or crap brakes, or for mac strut vs. double wishbones. I do get and should get a torque adder.

Well, step back. My car has actually not been through the process. If you run it at any normal IT power gain it comes out ridiculously low due to its low stock hp. But if you run it through wtih teh standard adders/deductors, you would just get one torque adder.

We don't do anything for live rear cars (nor do I think we should), or BAD brakes (just good ones), or for mac strut cars in ITS (that I am aware of).

Chip, we did know when creating ITR that some of the tweener cars were going to be at weights that were difficult to achieve. There will always be tweeners, that fall in the too heavy in the lower class, too light in the higher one, that are just hard to deal with. The Celica GTS certainly is one in R -- it could be an S car, but the weight it would require would probably make it entirely unattractive there as well.

Ron Earp

01-22-2009, 11:12 PM

Jeff - you know the process better than me, but doesn't your car get a stick axle adder, a drum brake adder, and a strut adder (all negative) and a torque adder (positive), too?

No, it doesn't. The point is if someone wants to argue for a FWD break couldn't a racer argue for breaks for these attributes as well?

Andy Bettencourt

01-22-2009, 11:17 PM

At SOME point, IT is just gonna have to be 'what it is'. And currently, many think its the best ruleset in the SCCA.

Finding that 'is what it is' point is tough. Everyone has a different view of where it should be.

Chip42

01-22-2009, 11:18 PM

Jeff- out of curiosity, what would the TR8 weight be "by the process". note that I am in no way trying to assail the car or you - I have nothing but high regards for you from the limited face time I have had and I would love to see the '8 do well. I have no vested interest in ITS at all, at most a friendship with Scott Seck, but he holds his own quite nicely, thank you.

ron - I thought that these were active adders. been wrong before, sure it will happen again. my experiences are building FWD ITA and prod cars and MR2s and inspecting, not so much driving and rules making.

but I would think, in the spirit of this discussion, that race-length detriments over "normal" equipment (drums, solid disks, stick axle as it induces odd tire wear,...) should be considered, either way. FWD is just another one to add to the list (albeit a big nasty one)

Ron Earp

01-22-2009, 11:19 PM

No ITR 944S2 on pg 344? I must have written my own GCR then.

I was following the discussion about weight and HP and their effect on differences in laptimes of FWD and RWD cars across all IT classes. I also had two convenient models already on my machine.

Alex

Sorry, forgot about that and I actually owned one up until Dec 2008. Was thinking too much about ITS/ITA and the discussion at hand.

Anyhow, I understand what you're saying about the models but comparing an ITA FWD car with an ITR RWD car isn't going to clearly define how much weight, or an approximate weight, should be on the cars to equalize them with a 100hp difference.

Ron

Ron Earp

01-22-2009, 11:20 PM

At SOME point, IT is just gonna have to be 'what it is'. And currently, many think its the best ruleset in the SCCA.

Amen.

Andy Bettencourt

01-22-2009, 11:21 PM

You for sure want to compare cars from the same class....

JeffYoung

01-22-2009, 11:29 PM

Chip, absolutely no offense at all. Ask any and all questions, please -- I'm serous about that. And yes, Scott is damn fast in his car, I finally saw it at Daytona (although the clutch exploded I think) and that is one nice GSR.

Process weight on my car would be:

133 stock hp * 1.35 (highest present IT power modifier) * 12.9 + 50 for torque = 2366, or TWO HUNDRED pounds less than what it is now. I could probably get the car down to 2500 if I had too, but even that weight is too low and, honestly, if the FI motor makes what we think it might then the 35% gain is too low as well. We'll see.

Also, the adders are far simpler than you think. I don't have the specifics right in front of me, but it basically is and adder for torque, an adder for double wishbone (I personally think we need to do away with that) and an adder for brakes (same).

Jeff- out of curiosity, what would the TR8 weight be "by the process". note that I am in no way trying to assail the car or you - I have nothing but high regards for you from the limited face time I have had and I would love to see the '8 do well. I have no vested interest in ITS at all, at most a friendship with Scott Seck, but he holds his own quite nicely, thank you.

ron - I thought that these were active adders. been wrong before, sure it will happen again. my experiences are building FWD ITA and prod cars and MR2s and inspecting, not so much driving and rules making.

but I would think, in the spirit of this discussion, that race-length detriments over "normal" equipment (drums, solid disks, stick axle as it induces odd tire wear,...) should be considered, either way. FWD is just another one to add to the list (albeit a big nasty one)

JeffYoung

01-22-2009, 11:36 PM

That is where I am headed.

Stock hp * 1.25 in almost every case with a torque adder, and that is IT. Nothing else. No suspension modifiers. No brake modifiers. No live rear axle modifiers. No aero modifiers. No wheelbase modifiers. Nothing.

I accept Greg's position that FWD is a disadvantage. But I don't see anyway to quantify "how bad it is" versus other disadvantages we don't and have no intention of quantifying.

And this is IT. No guarantee of competitiveness. Build your car, and man up and drive it (and its disadvantages). Most of us do that anyway.

BUT THAT'S WHAT WE'RE TRYING TO AVOID: Making judgments by our guts, pulling numbers out of our butts. That said, I'd endorse your idea of doing away with variables if that's what it took to get consensus around a repeatable, transparent process that considers physical attributes of the car and doesn't allow for butt-number-pulling.

K

esuvee

01-22-2009, 11:42 PM

... but comparing an ITA FWD car with an ITR RWD car isn't going to clearly define how much weight, or an approximate weight, should be on the cars to equalize them with a 100hp difference.

Ron

That's not at all what I was doing, I was 'creating' a FWD 944 and comparing it to an as produced RWD 944. Same with the CRX, I took my model of my CRX and 'created ' a RWD CRX. The reason for the two cars was to reinforce that power is a big deal in this equation. I should have included a table:

ITR 944 RWD - 2:01.75
ITR 944 FWD - 2:03.48
ITR 944 FWD minus 250lbs - 2:01.83

ITA CRX FWD - 2:07.9
ITA CRX RWD - 2:07.0
ITA CRX FWD minus 115lbs - 2:06.98

The only difference between my anecdotal examples and Mike's work are that I changed many factors on the 'created' cars that a racer would change to 'optimize' a FWD or RWD car to get an accurate idea of what part of the FWD disadvantage can be made up with suspension tuning.

His table is perfect for comparing trends of weight and power, I am trying to find anecdotal examples of what weights might work. None of this will result in a perfect equation, just more info for everyone.

Alex

ekim952522000

01-23-2009, 01:00 AM

ekim952522000

01-23-2009, 01:03 AM

That is where I am headed.

Stock hp * 1.25 in almost every case with a torque adder, and that is IT. Nothing else. No suspension modifiers. No brake modifiers. No live rear axle modifiers. No aero modifiers. No wheelbase modifiers. Nothing.

I accept Greg's position that FWD is a disadvantage. But I don't see anyway to quantify "how bad it is" versus other disadvantages we don't and have no intention of quantifying.

And this is IT. No guarantee of competitiveness. Build your car, and man up and drive it (and its disadvantages). Most of us do that anyway.

Why'll that does not "sound" bad I think it would make people very unlikely to race FWD in anything above ITA.

Jeff I still don't agree with your logic you said "....I don't see anyway to quantify "how bad it is" versus other disadvantages.....How do you quantify the torque adder than?

I could accept your logic if you said IT should be stock hp * 1.25 and that's it. But then you throw in the torque thing...

shwah

01-23-2009, 01:09 AM

At SOME point, IT is just gonna have to be 'what it is'. And currently, many think its the best ruleset in the SCCA.

Quoted for super extra maxi truth.

JeffYoung

01-23-2009, 04:00 AM

I'd take the torque out too, but it would be a "me" request because it would help my car, so I don't think it right for me to bring it up.

Why'll that does not "sound" bad I think it would make people very unlikely to race FWD in anything above ITA.

Jeff I still don't agree with your logic you said "....I don't see anyway to quantify "how bad it is" versus other disadvantages.....How do you quantify the torque adder than?

I could accept your logic if you said IT should be stock hp * 1.25 and that's it. But then you throw in the torque thing...

Jeremy Billiel

01-23-2009, 07:44 AM

Jeremy and Greg can give the details but I think they ran this year with just bolt-ons and an ECU. I think they wanted to do the suspension and then evaluate. Seems as if another thread had that car at around 180whp with all the balls and whistles. Probably 128-130ft/lbs of wheel toque max though.

The TYPE of 944 has to be defined...a regular 944 8V should be about 152whp. The CRX is about 130whp.

The Integra will hit IMO the 25% adder. There will be zero torque, but with a LOT of money you can build a 25% capable GSR motor.

Ron Earp

01-23-2009, 09:51 AM

Nice job Alex I have a new table that turned out very odd. I left everything the same but started with more of a FWD biased setup last time was more a RWD biased setup and used a 65% bias instead of a 60% and the results were quite different almost linear. The 65% front bias made the changes in lap time much less dramatic then the last table.

I also ran a 200hp FWD car with all different weight Bias to see how lap times were effected.

Interesting results. Seems to suggest that the times are more dependent on weight distribution than anything else. Also it appears the time difference between the two cars in relation to horsepower doesn't increase as much as it was expected. But, it is just a simulation.

In my opinion this thread has brought up some concerns in our classification process. Certainly one that stands out to me is why single out FWD as the factor that must be corrected for when there are clearly other factors that one could choose - brakes, weight dist, suspension, driveline, etc.

As Andy and Jeff have both stated in various ways, IT isn't broken. Far from it. Maybe it is best to deal with it as is and make the best of it. I do hope that if the ITAC considers the FWD adder that they will bear in mind that IT works pretty well.

Greg Amy

01-23-2009, 10:17 AM

...why single out FWD as the factor that must be corrected for when there are clearly other factors that one could choose - brakes, weight dist, suspension, driveline, etc.
Because next to engine output and weight, driveline layout is the most important factor in predicting performance (which is exactly what you're doing with the classification process). Though all this extra non-related stuff is muddying the waters, this fact remains apparent to anyone that understands front wheel drive cars.

I ain't sayin' that suspensions, brakes, axles, ad nausea don't make a difference; of course they do. But they don't make anywhere near the difference that ponies, weight, and the driving end does. I'd take a drum/strut/live axle RWD car long before I'd take a disc/multi-link/IRS FWD car, given equal engine output and weight. And you would, too, I bet.

Bottom line, treating drive layout with the same significance any of these other characteristics illustrates a basic misunderstanding of the vehicles' dynamics.

That's all I'm tryin' to say.

GA

lateapex911

01-23-2009, 12:59 PM

Why FWD?
While the actual act of driving the car thru the front wheels might, or might not, be entirely responsible for the cars deficits in lap times vis a vis equivalent RWD cars, we use it because it's a consistent and easy to identify trait. In other words, IF the real reason these cars are slower is the weight distribution, well fine. But the ITAC doesn't have that info. But the fact that FWD cars consistently have bad weight distribution helps the ITAC to adjust the process in a fair and transparent manner.

Do other cars that have crappy weight distribution get the dick sandwich? Yup. Oh well. But we need to use obvious "triggers", and the FWD spec is easy.

It's not perfect, and will never be, but it's better than classing two cars with equal specs other than driveline layouts at the same weight.

I think we just need to find appropriate "bogeys" for each class.

Jeremy Billiel

01-23-2009, 01:19 PM

ekim952522000

01-23-2009, 01:23 PM

I am with you Jake. So how do we go about creating these boguys? This is the challenge. We can model it out on LapSim, we can speak to it, I believe we ALL know the problem. Do we bump up the ITS and ITR deductions by 50 lbs each?

The only real stance i have on it right now is that I believe whatever deduction ITS get's ITR should get slightly more.

EDIT: But on second thought as I said earlier I don't think any of the ITR cars can get any lighter so it may not matter. It's also such a new class maybe it would be better to see how things shake out first.

<----------The more we talk about this stuff the more I realize how hard being on the ITAC would be. I can see how someone could just end up wanting to say no to everything but even that has it's problems..........

Andy Bettencourt

01-23-2009, 01:32 PM

The only real stance i have on it right now is that I believe whatever deduction ITS get's ITR should get slightly more.

I agree. 100/150?

125/175?

150/200?

This is the problem...we have identified the issue and we are at 100/100. 100/150?

Jeremy Billiel

01-23-2009, 01:38 PM

I agree. 100/150?

125/175?

150/200?

This is the problem...we have identified the issue and we are at 100/100. 100/150?

I would think 150/200 would be about right looking at the lapsim data.

Greg Amy

01-23-2009, 01:41 PM

...we have identified the issue and we are at 100/100.
200/250, but this is coming from someone who still believes in the Tooth Fairy... :shrug:

Eagle7

01-23-2009, 01:54 PM

[quote=JeffYoung;281605]That is where I am headed.

Stock hp * 1.25 in almost every case with a torque adder, and that is IT. Nothing else. quote]
I know this is the wrong thread, but I'd be interested to know what the distribution is of the HP multiplier used for cars that have been through the process. This seems like a hugely subjective part of "the process". I hope Kirk et. al. can make some progress in objectifying it.

Andy Bettencourt

01-23-2009, 02:00 PM

I would think 150/200 would be about right looking at the lapsim data.

Good. You guys are right at -150. :eek:

Ron Earp

01-23-2009, 02:15 PM

200/250, but this is coming from someone who still believes in the Tooth Fairy... :shrug:

So an ITS Acura Integra that weighs 2430 and 2590, depending on which model it is, would receive a 200 lb deduction off the current weight?

These cars put down the same rear wheel hp, or more, as any other S car. They have great brakes and a great suspension and in well-built trim, at least down here at VIR, they turn laptimes that are similar to the fastest ITS guys in strong fields.

I know we can't use on track performance to adjust the rules and that sort of thing, but dang, this would turn an already great car into a heck of a car to have in ITS.

I don't know how that would shake out in ITR. I doubt the Celica can acheive a 250lb break with out a remote control driver. I think the current weight is 22XX lbs.

I think I must have something screwed up. Don't the weights already reflect a 100lb deduction for FWD? So in essence the proposed deductions is X - 100lbs?

Andy Bettencourt

01-23-2009, 02:22 PM

So an ITS Acura Integra that weighs 2430 and 2590, depending on which model it is, would receive a 200 lb deduction off the current weight?

No Ron. It would change the FWD dedcution from 100 to 200lbs in Greg's scenario. Here is the GSR in a -150lb scenario for ITS.

170*1.25=212.5*12.9=2741.25

2741.25 -150lbs for FWD, -50lbs for lack of torque and +50lbs for double wishbone = 2590!

ekim952522000

01-23-2009, 02:27 PM

I agree. 100/150?

125/175?

150/200?

This is the problem...we have identified the issue and we are at 100/100. 100/150?

Something I would like the ITAC to consider is removing the -50lbs that FWD cars recieve for having struts. It is the only suspension modifier used in the ITR and seems out of place.

So in reality if we were talking about about some common FWD cars in ITR recieving a 150lb deduction instead of a 100lb the weights would look like this

Celica 2380 = same since it would not be getting the strut dedcuction
Type R 2535 = 2485
Prelude 93-96 = 2570 = 2520
Prelude(97-01) 2640 = 2590
RSX-S 2665 = same since it would not be getting the strut dedcuction
Legend 3135 = 3085

Which I think is very close to achievable for the cars with a 180lb driver.

Ron Earp

01-23-2009, 02:29 PM

No Ron. It would change the FWD dedcution from 100 to 200lbs in Greg's scenario. Here is the GSR in a -150lb scenario for ITS.

170*1.25=212.5*12.9=2741.25

2741.25 -150lbs for FWD, -50lbs for lack of torque and +50lbs for double wishbone = 2590!

Well, that is why I asked and put that last line in my post - I had to have had something screwed up!!!!

Greg Amy

01-23-2009, 02:33 PM

Good. You guys are right at -150. :eek:
Proving that I was right when I suggested the 200.

Again.

:shrug:

Andy Bettencourt

01-23-2009, 02:38 PM

Proving that I was right when I suggested the 200.

Again.

:shrug:

Based on what? That is the point Greg...what are you using for evidence that your car is 50lbs 'heavy'? How much is too much? 201lbs? 250lbs? 300lbs? The LapSim seems to support about 150 as Jeremy states, so when do we go too far?

ekim952522000

01-23-2009, 02:46 PM

Based on what? That is the point Greg...what are you using for evidence that your car is 50lbs 'heavy'? How much is too much? 201lbs? 250lbs? 300lbs? The LapSim seems to support about 150 as Jeremy states, so when do we go too far?

Maybe it's not the 150 FWD subtractor that's wrong maybe it's the 50lb add for double wishbone suspension?

Knestis

01-23-2009, 02:51 PM

Apropos of nothing (I LOVE THAT), I think the suspension adder is less meaningful by a long shot, than the FWD subtractor. Yeah - I'd love it if the Golf didn't push like it does but I think it can be worked out, and it's a smaller-magnitude thing than driveline configuration.

K

Tristan Smith

01-23-2009, 02:52 PM

so when it rains, do the front wheel cars have to add weight? Cause everyone knows the FWD cars have an advantage in the rain. So I propose that when ever there is a wet track, all FWD cars not only have to add the weight that you propose that they take off, but that RWD cars either get a weight break, or some lead has to be thrown in the FWD cars.

Andy Bettencourt

01-23-2009, 02:53 PM

Sweet, I'll take my 50lbs back thanks!

Seriously, I am having 3 off-line conversations on this right now. 2 that think 200lbs is CRAZY given equal suspension and equal power and one that seems to be going by 'feel'. I just want to know why 200lbs is 'more right' than 150lbs.

ekim952522000

01-23-2009, 03:04 PM

No Ron. It would change the FWD dedcution from 100 to 200lbs in Greg's scenario. Here is the GSR in a -150lb scenario for ITS.

170*1.25=212.5*12.9=2741.25

2741.25 -150lbs for FWD, -50lbs for lack of torque and +50lbs for double wishbone = 2590!

Andy do all of the FWD cars in ITS get the 150lb weight break right now? I think they might....I always thought it was 100......

Prelude Si
160*1.25*12.9=2580 + 50 DW - 150 FWD = 2580 current weight is 2555?

tnord

01-23-2009, 03:11 PM

this whole thing is a big heaping pile of poo from where i sit. this is a new approach to the same old agenda....."my car needs less weight."

it was maybe only a couple months ago certain people were campaigning that we should give the same % weight break to the ITS/ITR cars that we do for the ITA listings, it was argued that the ITA weight break was good and to use that as the bogey. that seemed like a somewhat reasonable request rather than the adders we have now. so i actually ran the numbers. my post from another thread talking about the power gains from Honda motors;

the last time this came up, it was said that the FWD "adder/subtractor" was correct for ITA, but for ITS and ITR it wasn't enough. so i actually took some time to see just what would happen, if we used the same % weight break for ITS/R as we do for ITA FWD cars.

i took 18 popular ITA cars, and came up with an average % weight break of 2.08. going through the list of FWD cars in ITS/R, % weight breaks for FWD ranged from a low of 1.58% for the Mitsubishi 3000GT, and a high of 2.06 for the Celica GTS. applying the 2.08% to all of these cars didn't change much, with 16lbs more coming off the the aforementioned Mitsu. the cars everyone likes to complain about flowed through as follows;

Integra GSR; -5lbs
Civic Si; -2lbs
Prelude VTEC; -11lbs
GTi VR6; -7lbs
Acura RSX-S; -6lbs
Celica GTS; -1lb

well since that didn't result in what the flag waivers wanted, here we are again....but this time they want a subjective weight break, and are trying to back into "data" to support it. FWD is already accounted for, and i know you claim it's the biggest issue outside of horsepower, but fuck me how much granularity do we need here?

if we really want to get that specific, then the convienently overlooked comment by someone a few pages back about how FWD cars suffer less drivetrain losses than RWD cars should be evaluated. after all, power is even more important than a FWD layout. lets give all FWD cars a 28% multiplier rather than 25.

i'm not buying this "for the good of the category" campaign BS at all. this is all about personal agendas and egos.

ekim952522000

01-23-2009, 03:26 PM

"Prelude VTEC; -11lbs"

190*1.25*11.25-2.08% = 2616 = 46lbs heavier than it is right now?
190*1.25*11.25-100=2571:shrug:

Greg Amy

01-23-2009, 03:35 PM

Greg...what are you using for evidence that your car is 50lbs 'heavy'?
Experience, Andy. Mechanical knowledge. Understanding of, and experience with, front-wheel drive dynamics. Observations of amateur and professional series that take parity seriously (try to find a series with otherwise-nearly-equal cars where the weight difference is less than 200#). "Gut" feel based on all of this.

Prove me wrong, Andy.

So what, pray tell, do you base your position on that I'm wrong, Andy? "Cause that's the way we do things"?

I recognize I'm in a tough position here. I think the subtractor's wrong, you don't. You drive a RWD car, I don't. You're on the ITAC and in all the committee meetings, I'm not. I have reasons to try and get it right, and you've got nothing but hassles from your RWD brethren if you try. You know that as long as you throw up yet another road block for me to hurdle, it just kicks the can down the road. Fine, it's crystal clear you hold all the cards.

Coupled to the fact I'm really getting tired of all the silly non-equitor arguments assaulting my patience and intelligence (Tristan, I'm game for adding weight to FWD cars in rainy conditions as long as you agree to add the same amount in the dry. You're writing a letter on that today, right?) For several days now I've been grilled, asked to support a position that no one else (well, no rear-wheel-drivers, anyway) seems to understand or believe. Each time I prove I'm right or support my position, someone else comes up with something else to argue about.

OK, I "get it".

Personally, it's not that important to me. I thought you wanted to know the real scoop, maybe learn something useful in the process. I have no misguided ideals that this particular car has a gnat's chance in this class (pretty much any FWD car is handicapped at ITS and ITR power levels, which is why most pro organizations give FWD cars extra prep "bones" to make them competitive). I simply used my personal example(s) as an outlying illustration of what I'm trying to explain to you, not as a lever to get the rules changed.

Regardless, you've got the data, you know my position. You may have even learned something in the process. The ball is now in your court for you to decide if you want to do the right thing.

GA

tnord

01-23-2009, 04:04 PM

The ball is now in your court for you to decide if you want to do the right thing.

the right thing from whose perspective? you want to base adjustments on experience? i have experience in both FWD and RWD cars. In fact, my miata and the CRX i drove in an enduro have the same power +/- 3hp. i had never driven a FWD car on track my entire life, and first session out, on corded 3 year old hoosiers, i turned a lap within .3 of my own best in my miata, and .1 off of where the owner qualified. that's my experience

your calling out the rest of us for disagreeing with an add'l weight adjustment for the same reasons you are for it. believe it or not greg, just because people disagree with you does not make them idiots. do you really think that Ron, Jeff, Andy, Jake, etc don't have the ability to hold the same level of mechanical knowledge that you claim to?

dickita15

01-23-2009, 04:07 PM

Andy Bettencourt

01-23-2009, 04:08 PM

Experience, Andy. Mechanical knowledge. Understanding of, and experience with, front-wheel drive dynamics. Observations of amateur and professional series that take parity seriously (try to find a series with otherwise-nearly-equal cars where the weight difference is less than 200#). "Gut" feel based on all of this.

Prove me wrong, Andy.

I am not here to prove you wrong Greg. I am asking you to prove yourself RIGHT.

So what, pray tell, do you base your position on that I'm wrong, Andy? "Cause that's the way we do things"?

You aren't listening. I am not telling you that you are wrong. I am WAITING for you tell me something other than 'because I said so'.

I recognize I'm in a tough position here. I think the subtractor's wrong, you don't. You drive a RWD car, I don't. You're on the ITAC and in all the committee meetings, I'm not. I have reasons to try and get it right, and you've got nothing but hassles from your RWD brethren if you try. You know that as long as you throw up yet another road block for me to hurdle, it just kicks the can down the road. Fine, it's crystal clear you hold all the cards.

I recognize you are in a tough position too. Knowing you, knowing that you are always playing the 'game' and knowing that you are a smart guy with plenty of experience, all I want is for something I can bank on if I bring this up in a meeting. The LapSim stuff is way better than anything we have seen or used. It seems to point to 150 as being pretty good. That is where I am now, still waiting for any more info.

Coupled to the fact I'm really getting tired of all the silly non-equitor arguments assaulting my patience and intelligence

Dude, you are the king of the smart ass comment... :)

For several days now I've been grilled, asked to support a position that no one else (well, no rear-wheel-drivers, anyway) seems to understand or believe. Each time I prove I'm right or support my position, someone else comes up with something else to argue about.

Point me to your proof and I will shut up. The fact that your car is effectively at 150lbs right now and you see that as 'proof' that it needs another 50lbs is not proof at all. What you are doing (in my mind) is taking your on-track experiences and applying the results. Yet the car is not developed in the HP department. Add that hp you will find into that SIM and see how much theoretical improvment you might get - assuming you want to compare lap times with Jeff...which I hope you aren't doing.

Personally, it's not that important to me. I thought you wanted to know the real scoop, maybe learn something useful in the process. I have no misguided ideals that this particular car has a gnat's chance in this class (pretty much any FWD car is handicapped at ITS and ITR power levels, which is why most pro organizations give FWD cars extra prep "bones" to make them competitive). I simply used my personal example(s) as an outlying illustration of what I'm trying to explain to you, not as a lever to get the rules changed.

Regardless, you've got the data, you know my position. You may have even learned something in the process. The ball is now in your court for you to decide if you want to do the right thing.

GA

And you finish out just like you started. 'I know it all, I tried to educate you for years, the info is obvious'...

I must have missed the data. All I remember is that you said it wasn't fruitful to provide data because you could make it look however you wanted.

There are plenty of us on the ITAC that want things to be right. We just need something to run with...and I can honestly tell you that I don't think you have given us anything. My sincere apologies if I missed it.

Greg Amy

01-23-2009, 04:18 PM

Andy Bettencourt

01-23-2009, 04:19 PM

Beer time!

+1. Drinking is better. :)

ekim952522000

01-23-2009, 04:21 PM

Honest question: there seems to be some agreement here that ITS and ITR FWD cars need more of a break due to the problem of higher horsepower cars putting too much stress on the front tires because of weight distribution and the front tires doing all the work. There is also a feeling from some R cars will need more that S cars. Is this higher need by the R cars at all mitigated by wider wheels and by extension tires allowed in ITR?

Ya know that is a really really good point.....Seriously

This may even explain why the 50lbs seems to work for both ITA and ITB.

on that note maybe it should should end up more like.

ITR - 150
ITS - 150
ITA - 50
ITB - 50
ITC - 0

Thoughts?

Knestis

01-23-2009, 04:53 PM

...I'm not buying this "for the good of the category" campaign BS at all. this is all about personal agendas and egos.

Damn. Secret's out. It's all part of my secret plan to get more weight added to my car.

:rolleyes:

Every math problem I've done around an initiative I support - displacement-specific HP factor, weight-based FWD adder, eliminate "bad rear suspension" subractor - even strict application of the process we have in place - has achieved exactly that, relative to others in ITB cars...

K

tnord

01-23-2009, 04:54 PM

Seriously, guys, I'm way done with this. There's really nothing else I can offer. Just take it for what it is.

I had to laugh out loud, though (honestly, not sarcastically!) I'd forgotten about Nord's tendency to stand behind the bigger folks and stick his head out once in a while, yelling "YEAH! WHAT HE SAID! TAKE THAT!"

:happy204:

No, really. I'm done now. Beer time!

Fuck off Greg.

or maybe it's just because I haven't had time to even shit the last two weeks from work priorities, and just today I got caught up on the topic. i'll gladly call out your ego as motivation whenever I see it, you know that.

"I can't win every race....the process must be wrong!!!"

same shit, different class.

lateapex911

01-23-2009, 05:03 PM

I recognize I'm in a tough position here. I think the subtractor's wrong, you don't. You drive a RWD car, I don't. You're on the ITAC and in all the committee meetings, I'm not. I have reasons to try and get it right, and you've got nothing but hassles from your RWD brethren if you try. You know that as long as you throw up yet another road block for me to hurdle, it just kicks the can down the road. Fine, it's crystal clear you hold all the cards.

Coupled to the fact I'm really getting tired of all the silly non-equitor arguments assaulting my patience and intelligence (Tristan, I'm game for adding weight to FWD cars in rainy conditions as long as you agree to add the same amount in the dry. You're writing a letter on that today, right?) For several days now I've been grilled, asked to support a position that no one else (well, no rear-wheel-drivers, anyway) seems to understand or believe. Each time I prove I'm right or support my position, someone else comes up with something else to argue about.

OK, I "get it".

GA

Greg, I have to call BS here. Really, even if it throws you over the edge into a real hissy fit.

You don't "get it"

Read back...people, believe it or not, can have different opinions than you, and some might even have legitimate points. Dick brings up the excellent point that ITR cars are allowed much wider rims.

I'm insulted that you've ignored my posts, which have supported your concept. But hey, it seems to me, from your comments, that just because the entire world isn't jumping on your exact numbers right away that you are crying that nobody supports you.

Well, don't be greedy, you've gotten plenty of support here from both sides of the aisle, and I for one have agreed with your general position. So has Andy.

I think this has been, with certain exceptions, a respectful discussion, and I see a lot of good coming from it.

Step back my friend, breath deep. Relax.

lateapex911

01-23-2009, 05:10 PM

on that note maybe it should should end up more like.

ITR - 150
ITS - 150
ITA - 50
ITB - 50
ITC - 0

Thoughts?

I'm cool with that, I guess, but I might bump ITR up to 175. I'd really have to look at the numbers closely -that's just my gut. But hey, we're all cool with doing things because our gut says to right??
;)

tnord

01-23-2009, 05:36 PM

Damn. Secret's out. It's all part of my secret plan to get more weight added to my car.

:rolleyes:

K

sorry Kirk, that wasn't directed at you.

Knestis

01-23-2009, 05:42 PM

sorry Kirk, that wasn't directed at you.

But I'd respectfully suggest that there are others who are in the same situation as I am.

I've had quite literally hundreds of conversations about these issues with Greg and, while you're going to need to take my word for it, he looks at them as objectively as anyone I know. He's a complete academic about this business.

K

ekim952522000

01-23-2009, 05:45 PM

I'm cool with that, I guess, but I might bump ITR up to 175. I'd really have to look at the numbers closely -that's just my gut. But hey, we're all cool with doing things because our gut says to right??
;)

I could see that making sense.

ITR - 175
ITS - 150
ITA - 50
ITB - 50
ITC - 0

Could I get some opinions on how how people feel about the FWD strut cars getting 50lbs off but no other cars in ITR getting any adjustment for suspension?

tnord

01-23-2009, 05:49 PM

But I'd respectfully suggest that there are others who are in the same situation as I am.

I've had quite literally hundreds of conversations about these issues with Greg and, while you're going to need to take my word for it, he looks at them as objectively as anyone I know. He's a complete academic about this business.

K

you're probably right, there are others in this thread who really are trying to improve the class. my comment was really for Greg, as many would've probably guessed.

sorry, i don't take your word for it.

hey, even i think the theory is correct. heavier and more powerful FWD cars should get more of a weight break than an 80hp civic dx. i even put in the time and effort to do the math and provide the results a few months ago. but are we really up to 100lb break for ITS/R already and some want to double that? sheesh. the ITR Integra Type R is what, 2500lbs and change? and how heavy are those 94+ ITA integras? yeah....i don't think doing it strictly by class is a good idea.

Andy Bettencourt

01-23-2009, 05:56 PM

I could see that making sense.

ITR - 175
ITS - 150
ITA - 50
ITB - 50
ITC - 0

Could I get some opinions on how how people feel about the FWD strut cars getting 50lbs off but no other cars in ITR getting any adjustment for suspension?

It is a different approach but the thought process is that the cars in ITR are all pretty advanced compared to a lot of IT cars. When you throw a car like the RSX Type S in there, we tried to balance it out by giving it (and any other car like it present or future), that -50lb 'adder'.

Andy Bettencourt

01-23-2009, 06:03 PM

But I'd respectfully suggest that there are others who are in the same situation as I am.

I've had quite literally hundreds of conversations about these issues with Greg and, while you're going to need to take my word for it, he looks at them as objectively as anyone I know. He's a complete academic about this business.

K

Objective or not Kirk, he either simply wasn't reading what was being written or he had some pre-conceived notions of what other people 'thought' that resulted in post #202 which was way off base.

Assuming that he isn't ever going to provide any data to support what he 'knows to be gospel', I have to continue to formulate opinions based on the excellent work Mike has been doing...and that is fine!

Like I said all along, give me something to work with if you want me to work with something!

ekim952522000

01-23-2009, 06:11 PM

..........i don't think doing it strictly by class is a good idea.

Travis I agree with what you're saying above the reason I have been focusing more on the idea of by class. is I think it would be more likely to get the go ahead by the ITAC.

I really do think picking a "bogey" for a class then using a adjusted pw/wt ratio is a better way to do it. But am not sure if it has as good of chance of going through.

I am really liking the 150lb thing for ITR if we adjust the pw/wt for FWD cars in ITR to 10.585. it gives the celica exactly a -150lb deduct. then the legend would get a -191lb deduct. the process weight I have shown is before any adders or subtractors so it would be up to the ITAC if they still wanted to apply the -50 for struts after runing it through the process. I think this is the most fair way to handle the situation but is also a kind of radical to change to the way things have been done.

Process FWD

--------------------------------------11.25-- 10.585
Toyota Celica GTS (00-02) ------- 2531-- 2382 -150
Honda Prelude (93-96) ------------2672 -- 2514 -158
Acura Integra Type R (98-01) ----2633 -- 2477 -156
Honda Prelude (non SH) (97-01)- 2813 --2646 -166
Acura RSX-S (2002) -------------- 2813 --2646 -166
Acura Legend (91-95) -------------3234 --3043 -191

lateapex911

01-23-2009, 06:57 PM

Process FWD

--------------------------------------11.25-- 10.585
Toyota Celica GTS (00-02) ------- 2531-- 2382 -150
Honda Prelude (93-96) ------------2672 -- 2514 -158
Acura Integra Type R (98-01) ----2633 -- 2477 -156
Honda Prelude (non SH) (97-01)- 2813 --2646 -166
Acura RSX-S (2002) -------------- 2813 --2646 -166
Acura Legend (91-95) -------------3234 --3043 -191

Mike, just so everyone is clear, the current process would subtract 100 fro FWD across the board on these cars.

So, what you're model proposes is a method of adjusting each model on a sliding scale. i like that, because it's rather blind.

Your result, for example, would remove an additional 66 pounds off the Prelude from it's current process weight, and 50 off the Celica, correct?

dickita15

01-23-2009, 07:13 PM

sorry, i don't take your word for it.

Travis, I like a good Greg bashing as much as anyone but you should trust Kirk on this one

Tristan Smith

01-23-2009, 07:29 PM

Coupled to the fact I'm really getting tired of all the silly non-equitor arguments assaulting my patience and intelligence (Tristan, I'm game for adding weight to FWD cars in rainy conditions as long as you agree to add the same amount in the dry. You're writing a letter on that today, right?) GA

If the weight is taken off the FWD cars I will write a letter. If being FWD is such a disadvantage in normal/dry conditions and you get a weight break, and you get the added advantage of FWD in the wet, aren't RWD cars being essentially penalized twice? I think ITR is way too early in it's deveolpment to be predicting which cars are going to be competitive and non competitive. Maybe you have a better argument for ITS. Fair enough, since there is some history to draw from. But whatever happened to the IT credo of you living with whatever strengths or weaknesses of the car you choose to race? I saw no advantage racing a 240sx RWD drive car in ITA as the Integras and CRX's smoked my ass lap after lap.

I thought I was bringing up a somewhat valid point that having an advantage (for either FWD or RWD) is also a bit subjective depending on the conditions. If I raced in Phoenix, RWD advantage. Seattle, FWD.

And Greg, you take cheap-shots all day long at people. Remind me to to ignore you next time I see you.

lateapex911

01-23-2009, 07:56 PM

If the weight is taken off the FWD cars I will write a letter. If being FWD is such a disadvantage in normal/dry conditions and you get a weight break, and you get the added advantage of FWD in the wet, aren't RWD cars being essentially penalized twice? I think ITR is way too early in it's deveolpment to be predicting which cars are going to be competitive and non competitive. Maybe you have a better argument for ITS. Fair enough, since there is some history to draw from. But whatever happened to the IT credo of you living with whatever strengths or weaknesses of the car you choose to race? I saw no advantage racing a 240sx RWD drive car in ITA as the Integras and CRX's smoked my ass lap after lap.

I thought I was bringing up a somewhat valid point that having an advantage (for either FWD or RWD) is also a bit subjective depending on the conditions. If I raced in Phoenix, RWD advantage. Seattle, FWD.

And Greg, you take cheap-shots all day long at people. Remind me to to ignore you next time I see you.

Tristan, on the surface, I can see your point about the wet weather advantage, but, don't be too sure. My only ITA wins have come in the rain, and I drove by FWD cars that smoke my little live axled torqueless RX-7 in dry conditions, driven by guys who have ARRC medals..

You'd think that the RX-7, known for it's tail out histerical behavior would be hard pressed (esp driven by me!) to keep up with the more forgiving front heavy FWD Integras, etc, but in our little racing world, that's actually not the case. The FWD cars need pretty significant set up changes to run well in the rain, and often changing weather conditions, limited time and limited crew resources means they race on a compromise setup.

Point being that as an classing body, we need to concentrate on standard conditions and let the chips fall where they may.

You made a point regarding the old IT crdeo of living with your warts.

I think that misses the broader point. If that were the case, we wouldn't bother classing cars, right?

In this case, we are attempting to find an appropriate response to a genre of cars. Now, in so doing, we will of course be cognizant that, as Dick points out, the rules allow a lot of rubber on the road for the ITR cars, and the resultant math will certainly account for that.

But..just because the rules allow 8.5" wide wheels and 275 section tires doens't mean that every ITR car can actually fit them. THAT's where the old credo comes into play. Choose your horse carefully, and live with it's strengths AND weaknesses.

Tristan Smith

01-23-2009, 09:06 PM

Tristan, on the surface, I can see your point about the wet weather advantage, but, don't be too sure. My only ITA wins have come in the rain, and I drove by FWD cars that smoke my little live axled torqueless RX-7 in dry conditions, driven by guys who have ARRC medals.

Yes, I agree, but then again we are told over and over that you can't use race results as a basis for rules changes. You may be a brilliant rain driver! Those other guys may have gone out with their dry set-up. And while I have never seen you drive, I am sure you ARE a brillant rain driver! But that is just my opinion. :)

In this case, we are attempting to find an appropriate response to a genre of cars. Now, in so doing, we will of course be cognizant that, as Dick points out, the rules allow a lot of rubber on the road for the ITR cars, and the resultant math will certainly account for that.

But..just because the rules allow 8.5" wide wheels and 275 section tires doens't mean that every ITR car can actually fit them. THAT's where the old credo comes into play. Choose your horse carefully, and live with it's strengths AND weaknesses.

Your right about the tire issue. No argument there. But we seem to be trying to fix issues (and this more related to ITR) before they have been proven to be a problem. My point in this is that a case has been made that all FWD cars are at a disadvantage. Yet when I made a broad statement that FWD cars have an advantage in wet conditions I am quickly told that I can't make a broad statement like that. And that that shouldn't be a consideration. Well if we are going to change rules, shouldn't all things be factored in?

I just want all factors to be looked at before we start changing things.

Knestis

01-23-2009, 10:26 PM

I don't think I see an issue, Andy, substantial enough for that later accusation. Or maybe I'm influenced by the fact that I have some frustrations similar to Greg's about this discussion. Or maybe I just missed something but I think that generally speaking, Greg is agreeing with the first principles that Mike is expanding on...

Or maybe, since Greg made it clear several pages before that he was basing his judgment on his experience, and since he was subsequently told that wasn't enough, he figured there wasn't much point in continuing to say over and over what he'd already said.

If we went back through this discussion and deleted every single post that made an assertion without "evidence" (your word, Andy), this thread would be about one page long. Mike posts Lapsim numbers and a half dozen people say in essence, "That doesn't feel right to me" (too much of a weight break), but they tend to be "anti-new idea." Sometimes "because I said so" seems to be OK, and sometimes it isn't, but the distinction appears to be dependent on the extent to which someone appears to agree with the position stated.

And I share what I *think* are Greg's frustration with what seem like disingenuous arguments...

But this is the Internet.

K

Knestis

01-23-2009, 10:29 PM

>> ...when I made a broad statement that FWD cars have an advantage in wet conditions I am quickly told that I can't make a broad statement like that.

I don't think anyone said that. The response -and I share the sentiment - is that we make our decisions on the conditions that we see the vast majority of the time across the country (dry) and not considering outlier tracks, that disproportionately reward particular features (a la Daytona). You can make those statements until the cows come home but the ITAC's got to establish braod guidelines and assumptions - every one of which is a compromise of some kind, where exceptions to the rules are concerned.

K

K

ekim952522000

01-24-2009, 03:36 AM

Despite everything else I still feel like this was a very valuable discussion.

I should try to clear up where I am coming from, basically I agree with Greg I feel like he is using sound logic and experience to make a request that he feels will help all FWD cars become more competitive within ITS.

BUT I needed to find to find something else to help back up Greg. So I thought that Lapsim would help me back up his theory.

To me Greg's theory was that the more power a FWD car had and the greater the mass of a FWD car the larger weight deduction it would need in order to make the lap times equal with a RWD car of similar design.
(Note: This may not actually be Greg's theory this is just how I took it)

I never intended Lapsim to give us the weights I just wanted to see if it backed up Greg's theory, and it did (twice). The question I then had to ask myself was given what a experienced racer and Lapsim are telling me what do I think a good "guess" would be for weights so I thought about it and said this.

Let's say that the FWD subtractor for ITA is correct. What that means then is that it is possible that the subtractor for ITS is correct, it is not likely that the subtractor is correct for ITR, ITB, or ITC.

Which made me think "assuming" the weights for ITS, and ITA were correct that the weights should probably look something like this

ITR - 150
ITS - 100
ITA - 50
ITB - 25
ITC - 0

But then there was this question.

Honest question: there seems to be some agreement here that ITS and ITR FWD cars need more of a break due to the problem of higher horsepower cars putting too much stress on the front tires because of weight distribution and the front tires doing all the work. There is also a feeling from some R cars will need more that S cars. Is this higher need by the R cars at all mitigated by wider wheels and by extension tires allowed in ITR?

Which set off a lightbulb in my head about something that had been bugging me all along. Why does the -50 seem to work for both ITB and ITA? That did not follow what everything else had been telling me. But Dick seemed to point out the answer, at least to me.

Which leads me to believe that again assuming the ITS "adder" is correct that maybe it should look something like this.

ITR - 8.5" -100
ITS - 7" -100
ITA - 7" -50
ITB - 6" -50
ITC - 6" -0

Well look at that, I think that is what we have. (not sure about ITC) But I am starting to think we have the "pattern" close enough.

Then this was posted

....... we seem to be trying to fix issues (and this more related to ITR) before they have been proven to be a problem. .........

This post concerned me because I think it must have looked like I was talking about ITR getting a weight reduction the whole time (I was, in a way, but let me try to explain) basically what I was trying to say was given the data IF we change the subtractor for ITS, to for example 125lbs then at a minimum ITR should be 150lbs. But after Dick made his post talking about tire sizes, now I feel like at the very least the subtractor for ITR should be the same between ITS, and ITR.

I also think that a adjusted pw/wt ratio would be a even better way to handle this but have no idea how the ITAC is supposed to answer when people say they want everything to use a adjusted pw/wt ratio instead of the simple adders and subtractors. So I understand using this method is very unlikely.

I think we should be using 150lbs minimum for both ITS, and ITR, But I have no way to prove that 150lbs makes anymore since then 100lbs.

Also of note is finding a way to work this out would go along way towards finding a solution to classing AWD cars. (Which I do think IT will need to do one day)

Sorry for the very long winded post but I wanted to summarize.:D

One last thing I am not clear on. Why is GSR currently classed using a 150lb subtractor. I'm guessing it was not adjusted during the great realignment do to the 100lb leave it alone rule and the math just happens to work out that way? If that is the case then it appears after the ITAC run all cars to within 5lbs of the process that the GSR will be gaining 50lbs.

Andy Bettencourt

01-24-2009, 09:29 AM

One last thing I am not clear on. Why is GSR currently classed using a 150lb subtractor. I'm guessing it was not adjusted during the great realignment do to the 100lb leave it alone rule and the math just happens to work out that way? If that is the case then it appears after the ITAC run all cars to within 5lbs of the process that the GSR will be gaining 50lbs.

Mike,

Many thanks for all your hard work. I don't recall anyone thinking this theory was bogus, we just needed to try and drill down and prove that there were 'better' numbers out there than 3x50 and 2x100.

On the GSR, it didn't get it's +50 for double wishbones when it was classed for some reason. That is why it ends up where it is if you re-look at the weight using the -150lbs for FWD.

Onto the ITR number. While Dick's thought process is 100% valid IMHO, I also feel like there aren't many FWD'ers that will be able to really utilize the 8.5" rim. I am betting most RWD guys will be able to try out a 275mm tire...255 for sure. I would doubt that any FWD car could stuff a 275 under the fenders with the current bodywork rules we have. So we need to compare the differences inside the class. I think there should be a difference when you look at it practically.

tnord

01-24-2009, 10:03 AM

Onto the ITR number. While Dick's thought process is 100% valid IMHO, I also feel like there aren't many FWD'ers that will be able to really utilize the 8.5" rim. I am betting most RWD guys will be able to try out a 275mm tire...255 for sure. I would doubt that any FWD car could stuff a 275 under the fenders with the current bodywork rules we have. So we need to compare the differences inside the class. I think there should be a difference when you look at it practically.

yeah but then you're getting into chassis specific allowances, and that's just not cool.

even accepting all of the downfalls of the FWD layout, i want to know why it makes more sense to arbitrarily pick a number for weight break rather than doing it as a % of min weight.

dj10

01-24-2009, 10:33 AM

Mike,

Onto the ITR number. While Dick's thought process is 100% valid IMHO, I also feel like there aren't many FWD'ers that will be able to really utilize the 8.5" rim. I am betting most RWD guys will be able to try out a 275mm tire...255 for sure. I would doubt that any FWD car could stuff a 275 under the fenders with the current bodywork rules we have. So we need to compare the differences inside the class. I think there should be a difference when you look at it practically.

As to date I've seen only the Porsche 944S2 able to use 275.40.17's and have not even seen 255.40 on any cars including the BMW's.

Knestis

01-24-2009, 10:36 AM

...even accepting all of the downfalls of the FWD layout, i want to know why it makes more sense to arbitrarily pick a number for weight break rather than doing it as a % of min weight.

That's the part of this that I'm still not getting. The only real responses I've HEARD (irrespective of what's been meant) are that "we can't do it perfectly, so the way we do it is fine," and suggestions that if we try to be more precise - more granular - about the FWD subtractor, then we'll somehow have to change policy to include additional factors into the weight-setting process.

I used the term disingenuous earlier but I think specious is a more apt term. But for consideration (one last time)...

1. We think drive layout is a consideration - That's a binary, yes-no decision that applies the follow-on math

2. Our theory is that mass and power aggravate the situation - do we have much dissent on this point?

3. We use power to set the weights - by a function, not in XX pound chunks decided upon subjectively...

4. Therefore, it's completely sound to set the FWD subtractor as a function of weight, power, or both.

Arguments against doing so also pointed out specific examples from math models that were being played with, where the outcome OF THAT SPECIFIC CASE, APPLYING THOSE SPECIFIC ASSUMPTIONS seemed "wrong."

Ultimately, I continue to get closer to the conclusion that we collectively WANT to be able to do what feels right - to do math reserving the right to reject it if the specific case outputs don't fit our preconceived notions. I also KNOW that six different people will have six different notions in any situation like that, unless they are purposefully picked to have matching priorities, goals, and interests around whatever is being discussed.

I'm also understanding more and more that I'm in the tiniest of minority of people worried about this.

K

Andy Bettencourt

01-24-2009, 10:46 AM

yeah but then you're getting into chassis specific allowances, and that's just not cool.

But isn't that the whole point behind a FWD 'adder'? I am thinking that FWD cars won't be able to utilize the additial wheel width - therby negating the theory that ITS and ITR cars should have the sames adder.

Just bouncing it around.

Here is where I am at currently:

ITR - 175
ITS - 150
ITA - 50
ITB - 25
ITC - 0

On edit: I think a % of min weight is a great idea - but in reality, wouldn't we be picking that % based on a pre-conceived number from charts like above? For example:

The base weight on a GSR is 2741...call it 2740. 150lbs is roughly 5.5%. So should we use a 5.5% subtractor for ITS?

Base weight on a typical ITA car is 2445. 50lbs is roughly 2%.

Wouldn't we be pulling these numbers out of asses? To me its real similar. In the 'static' method, lighter cars will have more % of loss but have less hp. In the 'dynamic' method, everyone gets the same % off but its based on hp numbers.

Show me the methodology behind determining the %'s...

tnord

01-24-2009, 10:56 AM

That's the part of this that I'm still not getting. The only real responses I've HEARD (irrespective of what's been meant) are that "we can't do it perfectly, so the way we do it is fine," and suggestions that if we try to be more precise - more granular - about the FWD subtractor, then we'll somehow have to change policy to include additional factors into the weight-setting process.

ok fine.....i accept that we can't do it perfectly.....but an arbitrary 200lb weight break is much riskier than an arbitrary 50, 100, or whatever it is these days. why? because what we have hasn't created any "overdogs" yet, and despite all the complaining, the cars aren't THAT far off. we know :p the GSR and Prelude can be competitive in ITS, and ITR is WAY WAY WAY too early in it's life to really determine anything.

I used the term disingenuous earlier but I think specious is a more apt term. But for consideration (one last time)...

1. We think drive layout is a consideration - That's a binary, yes-no decision that applies the follow-on math

agreed.

2. Our theory is that mass and power aggravate the situation - do we have much dissent on this point?

nope, not from me at least.

3. We use power to set the weights - by a function, not in XX pound chunks decided upon subjectively...

4. Therefore, it's completely sound to set the FWD subtractor as a function of weight, power, or both.

it's much better than "i think it should get AT LEAST 200lbs, let me go come up with some math to try and support it.

Arguments against doing so also pointed out specific examples from math models that were being played with, where the outcome OF THAT SPECIFIC CASE, APPLYING THOSE SPECIFIC ASSUMPTIONS seemed "wrong."

Ultimately, I continue to get closer to the conclusion that we collectively WANT to be able to do what feels right - to do math reserving the right to reject it if the specific case outputs don't fit our preconceived notions. I also KNOW that six different people will have six different notions in any situation like that, unless they are purposefully picked to have matching priorities, goals, and interests around whatever is being discussed.

I'm also understanding more and more that I'm in the tiniest of minority of people worried about this.

K

and this is exactly what i don't like....."this math doesn't fit my desires, let me go find something else." that's totally bunk. whatever math is used, if anything ever happens with this, should fit a couple known quantities (like the ITA integra), but beyond that it shouldn't matter if some people don't like the way it plays out for their cars.

you might be in the minority kirk, but you have to include me too.

Knestis

01-24-2009, 11:34 AM

But isn't that the whole point behind a FWD 'adder'? I am thinking that FWD cars won't be able to utilize the additial wheel width - therby negating the theory that ITS and ITR cars should have the sames adder.

Just bouncing it around.

Here is where I am at currently:

ITR - 175
ITS - 150
ITA - 50
ITB - 25
ITC - 0

On edit: I think a % of min weight is a great idea - but in reality, wouldn't we be picking that % based on a pre-conceived number from charts like above? For example:

The base weight on a GSR is 2741...call it 2740. 150lbs is roughly 5.5%. So should we use a 5.5% subtractor for ITS?

Base weight on a typical ITA car is 2445. 50lbs is roughly 2%.

Wouldn't we be pulling these numbers out of asses? To me its real similar. In the 'static' method, lighter cars will have more % of loss but have less hp. In the 'dynamic' method, everyone gets the same % off but its based on hp numbers.

Show me the methodology behind determining the %'s...

Broaden your thinking, Andy. An adder doesn't have to be a set number of pounds. We don't "add" 20 hp to the stock power to represent "IT power" - we ADD a number of pounds based on a factor. This idea just applies the same approach.

And we don't NEED a "methodology" to establish the math. It should just be a representation of our first assumptions about what we're trying to accomplish. Picking 5% for all S cars, based on a subjective assumption applied to ONE make/model, isn't necessarily a super-scientific way to get there but if we're comfortable with that as a first assumption, it's a hell of a lot better than picking a chunk to apply across the board.

MAYBE the only issue that's at play here is whether the same math has to be applied to all classes. I confess that I sort of assumed that to be the case but never really went that far in the calculations, because the roadblocks went up before I got to that point.

But I AM confident that applying -175 to all FWD R cars does a different thing for the Celica GTS (-7%) than it does for the Legend (-5%). And the error is in the wrong direction if our theory is that FWD hurts more as cars get heavier...

How about this, Andy - if you're confident with the numbers you list, plot each as a percentage impact on the weight (or power) outliers in each class and use the mean...?

K

Eagle7

01-24-2009, 12:17 PM

How about this, Andy - if you're confident with the numbers you list, plot each as a percentage impact on the weight (or power) outliers in each class and use the mean...?

K

And if that works, see if you can combine five equations into one that's class-neutral. Something as simple as

fwdsubtractor = (multiplier * itpower) - zerofactorpower

or some other equation that fits the data points for all the classes.

BTW, Kirk, I'm solidly in your minority.

tnord

01-24-2009, 12:34 PM

The base weight on a GSR is 2741...call it 2740. 150lbs is roughly 5.5%. So should we use a 5.5% subtractor for ITS?

Base weight on a typical ITA car is 2445. 50lbs is roughly 2%.

Wouldn't we be pulling these numbers out of asses? To me its real similar. In the 'static' method, lighter cars will have more % of loss but have less hp. In the 'dynamic' method, everyone gets the same % off but its based on hp numbers.

Show me the methodology behind determining the %'s...

we should use the same % across all classes, but i think it's a big no-no to just pick a number that your gut says "will get these cars competitive" (when some FWD cars already are).

the classes everyone is complaining about is ITS and ITR.....so if the 50lbs for ITA is right, then use that as your baseline, and since we accept the problem gets worse as weight increases, using the same % as ITA gets in all classes, and as their weight goes up, the weight break they get should go up as well.

i'm not so sure that power should be considered. tire abuse (but rear tires instead of front) goes up with power levels on RWD platforms just the same as it does on FWD, and even on ITA miatas you can't just stand on the throttle from turn in all the way out of the corner.

yes, even with some mathematical methodology you still have to arbitrarily pick your starting point. but you can't tell me that giving a 2500lb Integra a 200lb break and a 2800lb (or whatever) Mitsu 3000GT will have the same outcome.

lateapex911

01-24-2009, 12:45 PM

Mike,

Many thanks for all your hard work. I don't recall anyone thinking this theory was bogus, we just needed to try and drill down and prove that there were 'better' numbers out there than 3x50 and 2x100.

I'm with you here. I really appreciate Mikes and Gregs and Travis' and everyones contributions here.

Onto the ITR number. While Dick's thought process is 100% valid IMHO, I also feel like there aren't many FWD'ers that will be able to really utilize the 8.5" rim. I am betting most RWD guys will be able to try out a 275mm tire...255 for sure. I would doubt that any FWD car could stuff a 275 under the fenders with the current bodywork rules we have. So we need to compare the differences inside the class. I think there should be a difference when you look at it practically.

But I'm really NOT with you here, LOL. Tough nuggies if the wheel doesn't fit. The class allows it, we assume ...and when you pick your car, it's a factor the smart racer takes into consideration. IF we were to give breaks to FWD cars based on the assumption that they can't fit the allowable tire, then the RWD cars that also can not are getting the dick sandwich.

No, all cars are classed on the same assumption, and it's up to the driver/builder to do his homework. We must remain "blind" to model specific tire issues.

lateapex911

01-24-2009, 01:22 PM

Ok, just thinking out loud here.

ITR:

I chose a median weight for an ITR fwd car as 2880.

Since we use power to output weight, I think using weight is fine as a function. So I solved for a 175 adder at that median weight and got 6.0736%. Rounded up to 6.1%

Then i ran down the list:

Using Mikes list with weights from IT power already calculated
--------------------------------------
Toyota Celica GTS (00-02) ------- 2531- 154 = 2377
Honda Prelude (93-96) ------------2672 - 163 = 2509
Acura Integra Type R (98-01) -----2633 - 161 = 2472
Honda Prelude (non SH) (97-01)--- 2813 - 172 = 2641
Acura Legend (91-95) -------------3234 - 197 = 3037 (3135 process weight)

Then of course we do the adders and such.

net result, for ITR (I gotta go to work so ITS could be done later) is that heavy cars lose more, light cars less. Using that "bogey point" (admittedly chosen from the LApsim data and my 'gut (!) ) we get additional losses of as little as 54 pounds and as much as 97, but hovering in the 60 -70 range for most.

Thoughts?

tnord

01-24-2009, 01:38 PM

why does a roughly 2% weight break work perfectly for ITA but is apparantly 100lbs or so off in ITR?

JoshS

01-24-2009, 02:12 PM

But isn't that the whole point behind a FWD 'adder'? I am thinking that FWD cars won't be able to utilize the additial wheel width - therby negating the theory that ITS and ITR cars should have the sames adder.

It doesn't seem logical to me that FWD cars naturally have bodywork that's more restrictive than RWD cars. What is the basis for a statement like that?

Also, I prefer the fixed adder/subtractor approach than the math.

esuvee

01-24-2009, 02:40 PM

Two points to make now that we seem to be done with the factual side of the discussion:

1. Facts seem to show that ITS and ITR could use a bigger weight break than A, B and C. I think some earnest time on LapSim with some study of lap times (oh the horror!) to backup the LapSim models could produce and accurate number if one were desired. The laptimes wouldn't be to 'correct' the cars to equivalent laps, just to verify that the LapSim models produce the right results at the right tracks.

I feel like I missed the juicy part of this while I was away from the internets so...Rant On:

Greg seems to not desire an actual number and would rather have his vast experience pick as arbitrary a number as we currently have (what apparent idiot chose the current correction? clearly that guy was no greg:cool:). Even though in the first round of LapSim numbers Mike and I ran we came up with some backup for greg's ass numbers I don't agree with the 'vast experience' argument. It's a bit insulting to the group, the process and many of the members here who may, god forbid, know more then him on this subject but are still trying to do it the right way. Quite odd to start this whole discussion with no plan to back your position up.
Rant Off:

2. Even though I have some data to say that the current numbers might not be perfect I still have to ask what problem we are trying to solve. Is it that we have two classes not currently dominated by FWD honda products?

As an ITA CRX racer I aspire to one day build an ITR or ITS car that is more capable than my CRX. One big factor in this capability is RWD. If the GSR or a Prelude were the car to have in ITS/R I would be headed out of IT (what's the point of different classes if they have basically the same cars with a bit more motor?). The OK-ness of FWD ends when you need to take an engine's worth of weight out of the car to make it work, that's dumb and we're gaming the system if we do it.

Alex

ekim952522000

01-24-2009, 03:16 PM

So I finshed my final Lapsim session I could fill in more but I don't think it is needed.

By calculating the percent of weight break that was needed to get the FWD cars to keep up with the RWD cars Lapsim backs up the claim that why it is possible the 2% is correct in ITA 2% would most likely be wrong for ITS and be even farther off in ITR.

kophoenix32

01-24-2009, 03:20 PM

275/40-17 fit my 99 Firebird. Havnt done the set up work yet, I think the car will be heavy even with me at 180. Not quite done yet,but this is the car I chose so I will make it work. Testing in March!!!

Kurt Omensetter
Phoenix Auto Center
#39 ITR Firebird

tnord

01-24-2009, 03:21 PM

so this thing says that 150whp, 2500lb car (roughly an ITA integra) needs 150lb break to be competitive? really?

ekim952522000

01-24-2009, 03:26 PM

.........
........ One big factor in this capability is RWD. If the GSR or a Prelude were the car to have in ITS/R I would be headed out of IT (what's the point of different classes if they have basically the same cars with a bit more motor?). The OK-ness of FWD ends when you need to take an engine's worth of weight out of the car to make it work, that's dumb and we're gaming the system if we do it.

Alex

I have to respectfully disagree Alex while I do not expect a guarantee of competitiveness. I do appreciate that the ITAC is willing to try to get as close as possible. I accept at some point "it is, what it is" I just don't think we are quite there yet, close but not quite.

By "gaming the system" do you mean making it so FWD cars can race with RWD cars? Isn't that the whole point of the process to "try" to get things close? Otherwise you could say we are "gaming the system" by making it so a 180HP car can race with a 160HP car.

ekim952522000

01-24-2009, 03:28 PM

so this thing says that 150whp, 2500lb car (roughly an ITA integra) needs 150lb break to be competitive? really?

Please keep in mind that I am not suggesting we use the exact weights the results show. Since in order to do that you would need to do tons of sims with each pw/wt ratio and optimize the spring rates bars etc.. for each weight. I am just using it to show the pattern the as the HP goes up FWD cars need a larger percentage of weight taken off.

tnord

01-24-2009, 04:20 PM

Please keep in mind that I am not suggesting we use the exact weights the results show. Since in order to do that you would need to do tons of sims with each pw/wt ratio and optimize the spring rates bars etc.. for each weight. I am just using it to show the pattern the as the HP goes up FWD cars need a larger percentage of weight taken off.

is it saying that as power increases, FWD is at a bigger disadvantage, or is it saying that as power increases, a non-optimal setup has a larger effect?

ekim952522000

01-24-2009, 04:37 PM

is it saying that as power increases, FWD is at a bigger disadvantage, or is it saying that as power increases, a non-optimal setup has a larger effect?

Alex ran simulations earlier where he optimized the setup for both FWD and RWD which showed similar trends.

Andy Bettencourt

01-24-2009, 05:15 PM

why does a roughly 2% weight break work perfectly for ITA but is apparantly 100lbs or so off in ITR?

Trav:
This defines my issue with the %. Why is it 'off' Trav? Only because some have already accepted 150lbs as 'right'.

We can't use the same % for all classes because we have seemingly agreed that ITC cars need no break and ITB and ITA cars need a little and ITS and ITR cars need more.

If we used 5% for everyone (or insert your % here), there would be ITB cars getting more of a break than some ITR cars (2600lb ITB vs 2300lb ITR).

Josh:
It's about offset and how much stuff is under the fenders. FWD cars simply can't run as wide wheels are RWD cars under stock fenders as a general rule.

Kirk:
I am just listing numbers based on the LapSim piece. Here is the rub...I HAVE to use those numbers to get a target car. Here is what I get using stock crank hp numbers as a guideline:

ITR: 200hp. Base weight of 2812.5 rounded to 2815. 175lb target = 6.2%
ITS: 170hp. Base weight of 2741.3 rounded to 2742. 150lb target = 5.5%
ITA: 135hp. Base weight of 2446.8 rounded to 2447. 50lb target = 2%
ITB: 110hp. Base weight of 2337.5 rounded to 2338. 50lb target = 2.1%
ITC: 100hp. Base weight of 2355 rounded to 2355. 0lbs = 0%

So in this scenario:
Taurus SHO at 220hp would get a -192 (191.81) adder.
Contour SVT at 200hp would get a -174 (174.37) adder.
Celica GTS at 180hp would get a -157 (156.94) adder.

I applied the 6.2% right to the base weight before any additional adders were applied.

I can certainly buy this stuff. My only point was that we used our 'assumptive' target numbers as the basis. BUT - because they were derived from something like LapSim and we then try and apply it evenly, I can get behind it.

Does it pass the sniff test?