June Fastrack Out

[seckerich]

Sorry to come late to the party. Been out loading for CMP. Yes the Koni Challenge cars are spot on an IT build and were free ECU until this year. The numbers I posted were from a front running car (don't ask which one) and were all done on the same Speedsource Dynojet. I have used the same dyno for my ITS car and got within 2 hp from there to dynolab in atlanta and to a Dynojet in Asheville so I am pretty confident in my numbers. The rear wheel on those 2 cars does show almost 15%. You have to stretch pretty far to believe it looses 66 hp in the driveline. Was the original car a little of a pig--yes it seems so. Did Motec M600 and a very good exhaust and 3 years of tuning fix it--yes. At your assumed driveline losses that puts the motor at 275.3 hp (theoretical) Now apply those same numbers to other cars and they don't pass the smell test.

Reality check here. Do you honestly believe that 195 or even 205 rear wheel with 140-145 ft of torque is a match for a 215 hp 225 ft of torque BMW at the same weight, let alone at 215# heavier. Get a grip guys, something is wacked in this equation. The S2000 is in the same boat. You have got to realize that somehow torque has to be considered a little more than a trivial 100 pound drop. We give up 70# rwtq to the BMW. It is the same with most of the big 6 motors in the class but the BMW is the only one I have first hand knowledge of the numbers on and that has been publicly admitted to in the SIR debacle. I have seen more but will stick to the established numbers. I would have welcomed this discussion before the ITAC published the classification. I would have been happy to provide information to the CRB but never got the chance. All we got was it was being looked at and then it is in fastrack.

[JeffYoung]

I go back and forth and back and forth on this. I see and understand the ITAC's commitment to process, but if the process produces THAT result...WTF? I mean the RX8 has no chance against the 325is, the 944S2 and even the Mustang V6 at that weight, whp and wtq. Makes no sense.

The difference with the S2000 to me anyway is way more stock whp, but I agree, generally the same issue.

. Do you honestly believe that 195 or even 205 rear wheel with 140-145 ft of torque is a match for a 215 hp 225 ft of torque BMW at the same weight, let alone at 215# heavier. Get a grip guys, something is wacked in this equation. The S2000 is in the same boat. .

[Tak]

I am puzzled at the accounting for torque comments. The correct process is straight forward but tedious. You need torque vs RPM data, you need the gear ratios (including final drive) and you need the wheel radius.
From this data you generate a plot with torque on the Y axis and MPH on the x-axis. You will create a torque vs speed graph for each gear.
You end up with a a series of overlapping torque curves. (1 curve for each gear). A side benefit of this graph is it will show you exactly where to shift (where the curves cross). Equalizing cars then involves finding the area under the curve for a given speed range (say 30 to 120 mph), and multiplying by the vehicle mass.
As I said, this method is tedious, but will correct for both HP/torque disparity and for gearing issues.
Josh- You are local--I'd be happy to get together with you over lunch one day and show you the spreadsheet I worked up for my Rx-7.
Food for thought: F1 cars don't make torque either, but they are plenty fast in a straight line...

Tachi (Tak)

[dj10]

Grafton, thanks.

So, Grand Am Renesis gets header, open exhaust, open ECU and intake. Basically IT prep?

Jeff, you forgot injectors.

[seckerich]

Jeff, you forgot injectors.

We use stock injectors Dan. Barely see 60% duty cycle.

[Knestis]

>> I do think it would have been a good idea to have erred slightly on the light side - maybe have fudged some of those subjective factors a little - and get some of these cars on track, and then see if they needed adjustments

.

Think VERY carefully about this statement. While it's sensible as far as it goes (in terms of the motivation to build and therefore likelihood of seeing cars on the track) this approach codifies competition adjustments (bleah!) EXACTLY like they are implemented in Production - post hoc changes in specification based on on-track performance. Are you ALL ABSOLUTELY POSITIVE that you want to go down that road?

I am ABSOLUTELY POSITIVE that I do NOT and I take it as part of my mission on the ITAC to keep us from going there.

K

[dj10]

We use stock injectors Dan. Barely see 60% duty cycle.

That's wild considering you are making HP up to 8500 rpm. I am wondering if torque is such a big deal how the Mazda's are beating Pontiac & Porsche, which both have tons more torque?

[chuck baader]

DJ10...what matters is torque applied to the rear wheels. You must look at the gear ratio. I suspect the Mazdas are using a 5+ gear while the other cars are using a 3 or 4+ gear. Multiply the available torque by the gear ratio to get applied torque. Chuck

[lateapex911]

That's wild considering you are making HP up to 8500 rpm. I am wondering if torque is such a big deal how the Mazda's are beating Pontiac & Porsche, which both have tons more torque?

Huh?

I think you mean in the Rolex cup races? With the banner Racing Pontiacs? Those Speedsource RX-8s, if I have a clue, are 3 rotors...(right Steve?) a MUCH different animal, and THAT class is Ad-jus-ted!

[dj10]

Huh?

I think you mean in the Rolex cup races? With the banner Racing Pontiacs? Those Speedsource RX-8s, if I have a clue, are 3 rotors...(right Steve?) a MUCH different animal, and THAT class is Ad-jus-ted!

Sorry, I guess two different subjects. So I guess the 3 rotor makes gobbs more torque than the 2 rotor. I didn't mean to imply that the Rolex RX-8 was anything like the ITR RX-8 would be. I also under stand that the Rolex RX-8 is like the NASCAR car are to their OEM versions.

[erlrich]

.
this approach codifies competition adjustments (bleah!) EXACTLY like they are implemented in Production - post hoc changes in specification based on on-track performance. Are you ALL ABSOLUTELY POSITIVE that you want to go down that road?

I understand your concerns Kirk, but at the same time have to ask how you reconcile them with "At the end of the second, third, and fourth years of classification, the vehicle’s racing performance relative to other vehicles in its class shall be evaluated. If the Club deems that, in the interest of fostering greater equity within a class, a vehicle should be reclassified to another Improved Touring class, such a reclassification shall be made. Alternatively or additionally, if the Club deems that an upward or downward revision in the minimum allowable weight is warranted, such a "performance compensation adjustment" shall be made."?

Seems to me we've already codified something like competition adjustments? And while I don't really want to see Prod type comp adjustments in IT either, I don't really think what I suggested was quite the same thing; at least no more than PCAs are competition adjustments. What I am suggesting is that there is already some 'wiggle room' built into the process, in the form of the subjective adders, and that this is where the ITAC could work to help ensure a car doesn't die on the drawing board. And I know you of all people Kirk dislike the subjective part of the process, but until there are hard and fast formulas in place to account for all of the additional factors that must be considered when classing a car we're going to have to live with them.

Besides, I have the utmost faith that the current ITAC is the last group in this club that would allow true comp adjustments into IT.

[JeffYoung]

Yup, subjectivity is necessary. Especially when the process used solely objectively produces the following result:

E36 BMW 325is: Weight: 2780, KNOWN min. whp: 205, KNOWN min wtq: 200

RX8: Weight: 2980, KNOWN MAX whp: 205, KNOWN MAX wtq: 140

Maybe no guarantee of competiveness justifies this, I don't know.

[its66]

Sorry, I guess two different subjects. So I guess the 3 rotor makes gobbs more torque than the 2 rotor. I didn't mean to imply that the Rolex RX-8 was anything like the ITR RX-8 would be. I also under stand that the Rolex RX-8 is like the NASCAR car are to their OEM versions.

yep, very different beasts. Look at the rolex RX8 weight and the weight of the other, more "torqueified" entries. It is 500+lbs lighter than the Pontiacs, and 325 lighter than the Porsches. But, apples and oranges other than to say that for some reason, GA thought the RX8 needed to be lighter to be competitive.

Chuck,
I'm no expert, but I would think that when you run a car on a dyno, through the actual transmission, R&P, and tires that the car will be run on the track with, that you would be measuring the torque applied to the wheels. I do understand basic torque multiplication, but does it, or does it not show up when making chassis dyno pulls??

[dj10]

I've seen RX-8's run at ARRC last year in ITU (under a certain weight), what configuration were they?

[chuck baader]

Jim, I understand your point and I'm not sure I can competently explain. At 5250 rpm, torque and horsepower cross on a dyno sheet. Torque is generally going down as HP goes up. Because of the high RPM, those cars run a much lower gear. On a car that is RPM limited, while they can make more torque down low, they are limited by the taller gear they must run. Also, it does not seem to matter what gear (transmission) you run on the dyno, the results are very similar.

Now, let's get some of our more learned colleagues to chime in. Chuck

[JoshS]

Yup, subjectivity is necessary. Especially when the process used solely objectively produces the following result:

E36 BMW 325is: Weight: 2780, KNOWN min. whp: 205, KNOWN min wtq: 200

RX8: Weight: 2980, KNOWN MAX whp: 205, KNOWN MAX wtq: 140

Maybe no guarantee of competiveness justifies this, I don't know.

Jeff, this drives me nuts. The "minimum" BMW numbers are that high? Pretty sure there are LOTS of BMW's out there with lower numbers than that.

And the maximum is known on an RX-8? With one never built to the exact ruleset? How can you possibly know that it's the max?

And before we go comparing wheel horsepower numbers, I still want to see the test I proposed earlier, because the SAE correction factors have a bunch of assumptions about engines built into them. I could be wrong, but a friend who understands this stuff much better than me explained that it could be an issue.

[JoshS]

I am puzzled at the accounting for torque comments. The correct process is straight forward but tedious. You need torque vs RPM data, you need the gear ratios (including final drive) and you need the wheel radius.

Hey Tachi,

I wouldn't mind getting together, but I think we all understand how to figure out the area under the curve. The issue is that it's not realistic for the ITAC to get the torque vs. RPM data for every car we class.

[Knestis]

Yup, subjectivity is necessary. Especially when the process used solely objectively produces the following result:

E36 BMW 325is: Weight: 2780, KNOWN min. whp: 205, KNOWN min wtq: 200

RX8: Weight: 2980, KNOWN MAX whp: 205, KNOWN MAX wtq: 140

Maybe no guarantee of competiveness justifies this, I don't know.

There is a HUGE difference between changing the engine multiplication "IT power" factor based on research and applying subjective decisions about what something should weigh. We CAN do the former. We can almost do the latter with the PCA process, but it scares the crap out of me. True subjectivity applied at the unit of each model considered is totally not OK.

(PS here to anyone who opposed the IT-to-National-status initiative - you can have your worst nightmares come true, even leaving IT Regional-only, but going down this road.)

We might also change the math behind the process to more satisfactorily consider torque, since it sounds like that's a factor here. I'd like to better understand the ramifications and considerations of that, particularly since (the way my limited understanding goes) "HP" figures from most dynos are derived from direct measurements of, uh, torque...?

And I STILL argue that we don't "KNOW" what we think we know.

...and I'd be interested to know, since at least a few of us think the recommendation to the board was 100# fat, what you think that translates into in terms of lap time. Strictly as a mental exercise mind you, but I'm like that.

...and no, Jeff. Every car should have a shot at being in the game. Some will be closer than others but I don't believe that any ITAC members is kicking dirt on any make/model of eligible car with the "no guarantee" silliness.

Finally - and this is **REALLY** just Kirk talking...

...the tone of some of the posts here suggests that the writers believe that the ITAC's "got it in for Brand X." Please, SET IT FREE. We've got plenty on our plate trying to worry about the health of the category as a whole, without having to sit around figuring out ways to dink you. Yes - the committee is made up of individuals with differing biases, priorities, and perceptions. Yes - those perceptions influence individual decisions. But those biases are lost in the noise of translation to recommendations to the board through a process that's pretty close to consensus building.

K

[GKR_17]

The issue is that it's not realistic for the ITAC to get the torque vs. RPM data for every car we class.

I completely agree. This is why we need to be very careful using the torque number to set weights. All that actually matters is the hp of the engine in the usable RPM range. In general a high torque motor will have a 'flatter' power curve and won't lose as much power when shifting to a higher gear. But notice the ratio change in the transmission is highly important also. We clearly have an adder for torque, and I thought we had one for good transmission, but I don't hear much talk of it.

Here are 4 examples:

ITR BMW 325i (E36)
2nd-3rd: 33.7% drop
3rd-4th: 26.9% drop
4th-5th: 18.0% drop

ITR Porsche 944S2
2nd-3rd: 32.0% drop
3rd-4th: 26.1% drop
4th-5th: 19.7% drop

ITR Honda S2000
3rd-4th: 21.6% drop
4th-5th: 16.4% drop
5th-6th: 16.5% drop

ITR Mazda Rx-8
3rd-4th: 27.8% drop
4th-5th: 15.8% drop
5th-6th: 15.7% drop

Both of the low torque cars also have better transmissions, especially when you go down two gears from top. In addition, since the ratios are better, they may actually use 4 gears at some tracks where any 5-speed box will only use 3.

As an added thought - those familiar with the ITS Rx-7 know how much better the GTUs 5th gear is. The 0.71 5th gear in that car is a 29% drop, while the 0.76 5th drops 24%. Without that 5% better gear, that car has little chance in a tough field. Notice how much better than that both the S2000 and Rx-8 are for both 5th and 6th gears.

[JeffYoung]

It should drive you crazy because it shows the problem with the classification.

Here's what drives me crazy. I spent probably 200 hours over the last 2 years working on setting up ITR, developing the initial spreadsheet with Ron, participating in the ITR Ad Hoc committee, helping Ron with the V8 proposal (minimal, Ron did most of that), researching the RX8 proposal, and then doing the ITR spreadsheet clean up with you.

During all of that, I thought the goal of the "new wave" of IT thinking was to limit adjustments, keep rules stable, but not ignore the obvious. And most importantly to make all decisions as transparently as possible.

We put out the ITR spreadsheet for comment. I offered the V8 and the RX8 proposal, and dyno sheets (after a miscommunication with Steve), to anyone who asked BEFORE I submitted them.

I've read Kirk's post below and I frankly agree with most of it. I need to turn down the heat a notch, because I believe in the ITAC's integrity and commitment to preserving what we have.

But I am TICKED..I admit it...about:

1. That there was no "external" debate about the ITAC's proposed number before it went to the CRB. I did a lot of research on RX8 horsepower issues, and Steve knows a lot about gains. Offers were made to allow dyno testing of the Renesis, and there is information available from SCCA Pro on the motor that was not used. Why???? Why not take people up on this information to find out as much as you can about problematic numbers and THEN make the call. Would you still get heat over it? I'm sure, but at least you could say you went to great lengths to keep the process open to discussion, and member information input. I did more research after I submitted the proposal and had serious doubts about my own number. It's too low.

2. This one is directed directly at you, and I'm sorry about that. But I'm going to say it. Despite all of the work I did on researching the RX8 and power numbers, and all of the knowledge Steve E. and SCCA Pro have on it, YOU took it upon yourself to go get information from an "unnamed source" who doesn't want to be disclosed. YOU did this as someone who is in direct competition to the RX8. And now, you won't tell us anything other than you believe the stock hp number and the gain factor you arrived at because...someone told you so we know not who. Can you see how to others this might look a little off? I honestly don't think you had anything other than the best interests of the class involved, and I believe you are honest and have integrity. But just think about how that LOOKS.

I of course respect the ENTIRE ITAC, including you, for your volunteer efforts, and the hard work that you do (and all you get is shit from guys like me about it). After this, I do need to stop posting because I (a) have too much time invested in this one (even though I will end up cometing against the damn weedeater motor car!) and (b) consider all you guys friends. But I did want to throw out my concerns from my perspective in the hopes that maybe the classification process going forward will be more open.

I will also tell you that after spending the time that I did on the RX8 proposal, and Steve E. as well, to not be consulted AT ALL on some of the numbers we developed, why, how, etc....and then have the number come out like it did......makes it much less likely I ever undertake a classification effort again. I know this frustrated Steve a lot and he is a great resource on all things rotary.

That's all. You guys on the whole do great work. I just think you buggered this one (my opinion) and I think the process needs to be much more open. If we had this debate BEFORE the number showed up as the ITAC's classification recommendation and AFTER IT folks had an opportunity to comment on it prior to submission to the CRB, it would be much easier to swallow.

Jeff, this drives me nuts. The "minimum" BMW numbers are that high? Pretty sure there are LOTS of BMW's out there with lower numbers than that.

And the maximum is known on an RX-8? With one never built to the exact ruleset? How can you possibly know that it's the max?

And before we go comparing wheel horsepower numbers, I still want to see the test I proposed earlier, because the SAE correction factors have a bunch of assumptions about engines built into them. I could be wrong, but a friend who understands this stuff much better than me explained that it could be an issue.