Revised ITR list in Fast Track

Marshall:

CD of a 1992 325is is .32

I could only find CDs for M Roadsters in a quick check: ranged from .37 to .42. The later number maybe is with the top down.

Don't fall into the trap of "it's a sports car, the aero MUST be good." It's just not true. The best CDs out there right now are the Prius and the Insight because of the effect aero has on gas mileage. A Lamborghini Countach has a .42 CD, a Ford Taurus is a lot better.

Aero advantage, by a lot, to the 325.
Thanks. E-mail is [email protected] if you want to continue this discussion of line.

Jeff [/b]
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Jeff, I guess I'll go 1st. Your going to keep weight of a 2.8L the same as a 2.5L because of the CD?? We aren't talking F1, Champ or nascar here were talking about cars where the CD might be effective maybe 10% of the time during a race. If this is the case you have to figure them using someone to draft then using the torque of the 2.8L to pass the guy at the last turn. I'm not a areo space engineer, I was a pilot and I could get a plane to take off @ 55mph, but I do believe the CD may only have effects at speeds over 100 mph. I ask you why Chet never use a splitter on the nose of his BMW and still turned in the 1.39's @ RA? I may be wrong but if I remember right either did Rob Huffmaster have a splitter. Why? I understand sustained speeds of over 125 mph, but please this is IT. This is not a reason to keep a torque monster to a low weight. IMO :D



Repectfully submitted
 
Respectful reply:

1. I could argue that subjective on track performance like you mention is not what we should be discussing when trying to set "objective" weights. But I'll say this -- I drive an "open top" car. I can 100% tell you with absolute assurance that the open top KILLS my car about 100-110 mph, in other words, at end of the long straights at VIR, Road Atlanta, Charlotte and CMP. I've run nose to tail with Steve Echerich's RX7 (a stout one) up through the end of 4th gear and then watched him pull me 8-10 car lengths over the last 1/8 of the straight -- due to aero.

The lack of the splitter on Chet's car MIGHT be due to the fact that it creates more drag, and hence is car is faster (and has a lower CD) without it. Lots of folks tack on huge spoilers and splitters thinking they reduce drag but if not well thought out, they do not.

Aero matters. The 325 has a significant aero advantage over the Z3.

2. What is the difference again between the 2.8 and the 2.5 in torque? 20 ft. lbs? That is significant, I agree, but I think the aero and differences in rear suspension will compensate for it. Getting that extra torque down with trailing arms over curbs, bumps, etc. will be much harder in the Z car.

Guys, I firmly believe this to be the case: the ITR 325 will be as fast and probably faster than the Z3. And, again respectfully, I've seen nothing in the posts above to convince me otherwise.

However, Ron and I are just peons in this whole enterprise. We did the grunt work to start with, and the ITR a hoc and then ITAC confirmed the weights. If you guys truly believe the numbers to be wrong, you don't need to convince me. Write a well thought out, fact-based letter to the ITAC on it and see what happens. However again, understand that what I wrote above is I think pretty close to their thinking and you'll need to do some serious convincing to get it changed. However a third time, with the new PCA language in the ITCS, after initial classification, if someone goes out and whups up on the field in a 2.8 Z3, then there a mechanism to change its weight. I doubt it will happen (the whupping up), but if it does, it can be fixed.

Jeff
 
My friends experience in J-stock was that the shorter wheel base made for a lot of wasted motion. I guess he had a hard time as the sedans would just drive around him as he was fighting to keep the car pointed straight long enough to get power down. I imagine that Jeff knows of what I speak.

James
 
Respectful reply:

if someone goes out and whups up on the field in a 2.8 Z3, then there a mechanism to change its weight. I doubt it will happen (the whupping up), but if it does, it can be fixed.

Jeff [/b]
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Jeff, I do believe that a splitter used with a wing can make a difference, but in IT, no wings allowed. :D I do feel more comfortable know there is a mechanism in place to make some changes as long as we don't have to wait a long time to make the change. I've said what I felt I had to say.

James good luck on your Z3 project.

Dan
 
Thanks Dan,

Maybe we'll have to meet in the middle and race where neither of us has before, just to gauge how the two chassis stack up against each other.
 
I think it is best to see how it pans out and moves on from here. To me it is painfully apparent that the SIRs failed and further adjustments will be done with weight. With R getting a lot of air time I'm sure that adjustments will be made if a car is speced incorrectly.

R will be a tough class, even for BMWs. There is some serious hp potential in a lot of the cars, as well as good chassis/brake/suspension packages. As long as folks are realistic with expectations on competition adjustments I think all will be well.

Ron
 
Dan, thanks. Let's see how it pans out. The cars are less than 100 lbs different in weight right now. I know at least one class winning car in the SEDiv that is more than 100 lbs over its race weight -- so I think the difference will be far more driver dependent than the 100 lbs. But we'll see.

Jeff
 
At 3000 pounds, 100 pounds is what, about 3%???

I have to think that most of my laps have 3 corners where I have made slight mistakes that are more than 1% off....;)
 
Current version of the BMW list looks like this: Seem ok? Should teh Z3's get a small break due to the E30 rear suspension or is that compensated for with the 'nimbleness' a shorter wheelbase may provide? I think there should be a difference but putting a number on it is hard.

325 2765
328 2850
330 3290
M3 2700 (E30)
Z3 2850 (2.8)
Z3 3290 (3.0)

Still looking for imput. Jeff and I think there should be a difference. What say the Bimmer guys?

The FWD car DO have a slightly lower weight given the drivetrain layout. It amkes sense and is part of the process. Disagree with it fundamentaly if you want (as some have in letters) but it is the way the current committees see it.
 
up front, itr will be cool class and the effort put forth by all to make it happen is even cooler!

that said, starting with a clean slate is a great opportunity to get things as close to "right" up front as possible

comments like,
"itr will be tough class for the xxx cars, there are other cars with some serious hp potential"
and
"a diff of 100lbs can be easily overcome with driver skill"

are scary. if we think a car has massive hp potential, then that potential should be accomodated in the initial classing if possible, not found out in two years. driver capability should not even be discussed in the same thread with car classification. if someone is doing well 100lbs over min, imagine what they could do if they were at min? 20, 30, 50 lbs DOES make a difference in equal prepared cars with equal drivers. if it didn't, we might as well start rounding all car weights up to the nearest 100lbs..

getting into the nits of the classing discussion like what we are doing with the z3 is exactly what we should be doing. lets hash it out in the open so that we all understand the process and the inputs....and hence make the output better..i hope!

we all need to be "advanage neutral" and openly discuss percieved plusses and minuses to cars we are familiar with so next year we can have 10 different cars fighting for that checker.

lets not "settle" and rely on pca's to fix later what we can fix now. some great work has been done to get us this close. lets get busy with some 'nitpicking" to bring the class spec that final mile!

i am fairly familiar with bmw's so i started the picking on the z3 2.8. some points were made that it actually does have a little areo disadvantage, so i vote to give it a 25lb break off the 328 weight of 2850. 2825.

anyone see any other cars that appear too fast or slow?

marshall
can't wait for 07!!
 
i am fairly familiar with bmw's so i started the picking on the z3 2.8. some points were made that it actually does have a little areo disadvantage, so i vote to give it a 25lb break off the 328 weight of 2850. 2825.

anyone see any other cars that appear too fast or slow?

marshall
can't wait for 07!!
[/b]
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Seriously, I don't think the classing process has a resolution of 25lbs. And, I don't think you could bring any number of standard statisticaly tests to bear that would prove you right - or wrong. Sorry, I think that is simply too subjective and lost in the noise.

Ron
 
I would argue that the rear suspension is in fact more of a hindrance because of the short wheel base. Also the M50 intake is much better than the M52 or M54 units, why else whould there be a market for M50 intake swaps? I say split the difference 2800lbs, with the option of 2700lbs if it can't keep up no matter what. My friend was addament that it's NOT competitive in J-Stock last year, did they also adjust the weight down last winter? I'd not seen him in any of the results this year and the last event of last year he was driving a 328. Now how much of a lack of endorcement of the chassis is there than to switch out.

James
 
Fellows, fellows, we haven't even turned lap one in ITR yet. :P

As a side note - BMW Club racers do realize that J-Prepared isn't IT prep trim, right? I saw some comments in the BMW Club Footnotes magazine from last year that made me think there was little, if any, distinction to BMW Club racers. Throttle bodies and intakes are not free in IT. Neither are cams and cam duration. And a few other things like engine mounts, tranny mounts, etc.

Ron
 
Ron, JP and ITS are different but the reason for the confusion is that ITS cars are placed within the JP class at BMWCR. They run the IT weights and I think have been allowed to run without the FPR or SIR. A real full prepped JP car, however, will blow away a ITS car. It will be interesting to see if BMWCR keeps ITR e36 325 in the JP subclass.
 
Marshall,
You are on point with your comments. The weights are being set to TRY and hit the ground running with a level playing field. Many factors are taken into account but the facts remain that some cars will make more power than others and need to weigh more. The front drivers get a little reduction due to weight distribution and layout.
The ITAC voted last night to recommend to the CRB the following on the BMW's:
325 2765
328 2850
330 3290
M3 2700 (E30)
Z3 2800 (2.8)
Z3 3240 (3.0)
And - as a bonus for all the anti-ITR Bimmer guys - the ITAC also recommended that all ITS cars that are classed in ITR get a dual classification. Hopefully the CRB will go that way.
 
Marshall,
You are on point with your comments. The weights are being set to TRY and hit the ground running with a level playing field. Many factors are taken into account but the facts remain that some cars will make more power than others and need to weigh more. The front drivers get a little reduction due to weight distribution and layout.
The ITAC voted last night to recommend to the CRB the following on the BMW's:
325 2765
328 2850
330 3290
M3 2700 (E30)
Z3 2800 (2.8)
Z3 3240 (3.0)
And - as a bonus for all the anti-ITR Bimmer guys - the ITAC also recommended that all ITS cars that are classed in ITR get a dual classification. Hopefully the CRB will go that way.
[/b]
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Is the 328 a E-46 or a E-36?
 
I would argue that the rear suspension is in fact more of a hindrance because of the short wheel base. Also the M50 intake is much better than the M52 or M54 units, why else whould there be a market for M50 intake swaps? I say split the difference 2800lbs, with the option of 2700lbs if it can't keep up no matter what. My friend was addament that it's NOT competitive in J-Stock last year, did they also adjust the weight down last winter? I'd not seen him in any of the results this year and the last event of last year he was driving a 328. Now how much of a lack of endorcement of the chassis is there than to switch out.

James
[/b]
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we need to stop comparing to bmwcca results. bmwcca "stock" and "prepared" classes are both radically different than improved touring. stock is seriously limited in what you can do compared to scca, and prepared is way beyond what you can do in scca. results there have zero bearing on scca racing.

marshall
well aware of the differences between scca and bmwcca



Fellows, fellows, we haven't even turned lap one in ITR yet. :P

As a side note - BMW Club racers do realize that J-Prepared isn't IT prep trim, right? I saw some comments in the BMW Club Footnotes magazine from last year that made me think there was little, if any, distinction to BMW Club racers. Throttle bodies and intakes are not free in IT. Neither are cams and cam duration. And a few other things like engine mounts, tranny mounts, etc.

Ron
[/b]
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it actually pretty funny sometimes on the bmwclubracing list. there are prepared racers that appear truly scared of the potential of scca it cars! even though bmwcca prepared rules allow big wheels, big brakes, hot cams, big injectors, wings, splitters, etc..
 
... And - as a bonus for all the anti-ITR Bimmer guys - the ITAC also recommended that all ITS cars that are classed in ITR get a dual classification. Hopefully the CRB will go that way.

[/b]
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Argh.

My curmudgeon crystal ball tells me that's a decision we are going to live to regret. That's a policy decision - and a pretty huge conceptual departure from the norm in IT - that's been made to satisfy a tiny, pissed-off constituency. If we think that it doesn't set a precedent, we're wrong and we best be prepared to live with it.

Can I run my 325is in both S and R in the same season (switching wheels, etc. of course)? Is there any reason I HAVE to run in "official" R spec to enter? Can I do both on the same weekend? Can two different drivers? Do I need two logbooks, one for each class? Can I get my Golf be listed in ITC, too but at a higher weight because I'm having trouble getting it to its B minimum weight? It would be good for C since entries are kind of thin. I could decide which class I want to run depending on where the good (or weak) racing is. Can I qualify for the SIC in two classes with the same car?

"Hey, Kirk - why are there cars out there that look identical but are in different classes? That seems really stupid..."

K
 
Seriously, I don't think the classing process has a resolution of 25lbs. And, I don't think you could bring any number of standard statisticaly tests to bear that would prove you right - or wrong. Sorry, I think that is simply too subjective and lost in the noise.

Ron
[/b]
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car weights seem to be in -5- lb increments on the list...so classing is already operating at well under a 25lb resolution. yes it is subjective to a great extent. that is why were are having this discussion. other wise we would be rounding to the nearest hundred...or thousand.. :D
 
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