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

[jimmyc]

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....

[ekim952522000]

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]

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]

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]

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]

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]

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]

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....

I don't think you will find any posts where anyone said it wasn't a big deal. What was defined was the current process and what at the time was determined to be 'within the error of the process'. REMEMBER, this was a HUGE DEAL at the time and needed to be conservative when presented to the CRB/BoD in order for it to fly at all.

[Knestis]

...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]

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]

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]

... 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]

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]

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]

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]

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]

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.

Interesting idea Chip, but would adding the weight to RWD cars have the same effect? I don't think so and there lies the problem...

[Jeremy Billiel]

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]

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]

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!