A few of us 928 rennlisters have slowly been putting together track cars. Two of the group already race SCCA ITE class. When all of us are done, we will have at least five 928's that will be race ready. One of the group that actively races now has been told by local SCCA that if we can get five cars together, we can run our own class. All of the 928's are running stock chassis and stock suspension pick up points. We'll probably all end up running big red brakes and similar size rubber at some point, but for now everyone (except one) is running S4 brakes. We are all taking different roads to HP. Right now, 4 of the five cars are running 16v motors and one is running a 32v motor. I'm guessing there is maybe a 50hp difference between the weakest 16v'r (mine), which I'd estimate at 200rwhp, and the most modified (guessing 250rwhp), with the 32v'r probably pushing 80hp (280rwhp) [edit: Tom what did you pull on your last Dyno run? 300rwhp?] more than mine. All of the 16v'rs have boost in their futures, but I imagine this first season everyone will be NA.
We are all good friends, and to be honest I don't think a big spread in the performance specs of our cars is going to make that big of a difference on the track at this time with some of us being noobs. We've done DE's together and from my own perspective, even with an extra 50hp I'm not going to be keeping up with the more experienced racer's in the group. We're just looking to have a good time all racing our 928s.
So, if we do wind up in a position to write our own rules, what might be some things to consider? It would be nice to keep things simple and use a simple hp/weight index. We already know the maximum tires sizes and brake sizes that we can run and could list those as limits. All cars are similarly stripped and are or will be running the same cage. Stock suspension hard parts and locations but aftermarket shocks/springs/bushings. Can it be this simple and work?
Any input is appreciated.

 

Look at NASA's American Iron rules. They seem to be along the lines of what you describe.

 

NASA GTS rules are on a HP/Weight basis with verry little else. They may help you get a start.

The 2010 rules can be found here: http://www.nasagts.com/rules/2010%20GTS%20v1_1.pdf

 

A DYNO at the track !

 

If you are in the NW you should check out the new Sport Touring class in Conference (www.icscc.com). The class website is http://www.race-st.com

A bunch of us who were tired of running ITE against Vipers and Vettes did basically what you suggested. We made our own class and based it on pwr-to-weight ratio. The target car was a well developed e36 M3 but the rules are open for anyone that fits. There are a bunch of BMWs, a few Porsches, at least one WRX and several other types of cars that are going to run this year. I would bet a 928 could fit well too. All are welcome.

Eric

 

Toyos as the spec tire, ie no Hoosiers.

 

Thanks for the input everyone.

Eric, do you guys race out at Spokane as well?

 

Yes, racing at Spokane is a blast. This year should be a double race weekend, tenatively July 9-11. There are also races at Portland, Pacific, ORP and Mission.

 

Awesome. Just out of curiousity, what is a typical weight for a race prepped 968/944? (assuming they are similar). I see your car has NACA ducts in the hood, is it turbo'd? If so, what kind of HP are you putting to the ground? All of the 928's in our group are the earlier body style, and at race weight I would assume they would tip the scales at around 2700 lbs without the driver.

 

Weight of course depends on the class its prepped for. In a wide generalization you can get a late 944/968 into the 2500-2700 (no driver) range without going too crazy.

My car is a 2.5 liter turbo. I will have a map to put me at the 10lbs per rwhp class limit. Probably somewhere around 285 rwhp. With the gloves off the car is capable of a lot more.

 

You know my thoughts on the subject, but yes, as was said, the GTS rules are awesome for what most of us want to see out there. However, one gripe I have had on just hp/weight classifications with dyno results (of course, not like POC where the baseline is based on manufacturer owner manual values), is to have a factor for weight with driver. I have been fortunate to race with all sorts of different cars . what I have found is that the absolute weight is as important as a point or two of HP/weight as far as ratios. (i.e. I would rather race a guy with 8:1hp to weight vs my 9:1, at the same weight, than to have equal HP/weight ratios and me have 500lbs more car weight) This sounds like it isnt the problem, since you are all wanting to race a type of spec 928 class, where as we all know, the end weight is 2700lbs empty no matter what you do to those hunk of leads. I say the GTS class rules would work best, because it also has a rule to raise the HP value , on a car with a broader HP curve, or more peak torque (like the 32valver). actually, If I was going to make the rules and use a HP/weight value for classing, I would use average HP with 3 data points - @ max torque, @max hp and @ max rpm.
The rest of the stuff is important as well, but it all depends how much time you want to put in the rules and how complicated they become, as well as difficulty to enforce or even check.

Ive been racing ITE for a long time now. we tryied to narrow the scope to keep the budget down and the competition high. we thought by illiminating cars without real street VINs, (i.e. factory race cars like GT3, and comp coupes) that would be the solution, because who in their right mind would be converting street cars to near full WCGT specs. we were wrong. that happened almost immediately after our discussions. So, after seeing this, the only way to really restrict a class like ITE, which has provided some great, close racing, is to limit final HP/weight. in the end, the class control we were shooting for was just like GTS (GS4 which is about 8:1 Hp/weight)

sounds like you guys are going to have some fun regardless. make sure you make it down to Thunderhill this season so we can see the crew!

Mk

 

944Spec is 2600 WITH driver and most cars can make that (some later cars with husky drivers sometimes have an issue but not normally).

 

Isn't that a minimum weight? Seems like a bulemic driver will have more problems than a husky one.

 

Yes it is a minimum weight. I had to stop stripping the car long before I pulled everything I could out of it - but I have an 83 which is supposedly lighter than normal.

I weigh about 170 and last time on the scales I was at 2610 so I guess the car is 2440 as at the end of a race. One time I pulled the windshield wiper motor to use on my sons car and it put me under weight.

 

The ITE class up here I guess is pretty small. I think Ken Osage and John Davis said ITE had to run at the same time the GT1 class did last season. Ken was running a basically stock 4.5 with aftermarket engine management and John was running a pretty stock 4.7. We're talking what, maybe 235rwhp on a good day? They said the closing speed between their cars and the GT1's was just plain dangerous. John said he would get lapped about every 4th lap. I think the hope is that if there is enough of us out there, that we will be able to share the track with a different group.