New Rules for SCCA solo STU class
 

Per the December fastrack
I know cam is out there for our cars but they also go into STU and with the allowance of the diff tune... cant lie im looking at a parts list right now.

Can you post a link with more rule details. What's the PAX for Stu?

Here is the new PAX for 2021- https://www.solotime.info/pax/

315s are enticing, and it's nice that the class essentially allows all the bolt-on mods but doesn't encourage all kinds of cutting up and gutting of cars like CAM does. OTOH, the problem is the class also includes that AWD boost buggies and the mid-engine sports cars like the Cayman. The pax index reflects that (STU = .828 vs CAM-C's .818). That said, if you try it a lot of us will be watching!

I'm interested to hear why you'd choose to run in STU over CAM-C?

In reply to the above, it would technically be more limited prep compared to cam. The discussion of the 315 Rwd allowance was one of the final triggers for me to jump out of stu. It will completely change what cars can be more competitive now as there are a lot of rwd cars that can't mount a 3-series tire without fender modifications.. which aren't allowed in street touring classes (rolling only).

Yeah the boostie cars will be getting more power for sure. Caymans issue will always be wheel fitment, and talking to Camaro owners that also seems to be an issue with some coilover setups and wheel specs on our cars.

This is also probably the only year to try it as 2022 the supra and m2 cars will probably be moved into the class.

Simple, its a class with a jacket. Nothing wrong with cam, in fact I have to keep myself from wanting to do cam like things to the car, but STU is a SCCA class with a Jacket.. Yes cam has their own but its not the same.

Also PAX isnt a selling point for me. Yes locally its fun if you don't have anyone in a class with you but at nationals its irrelevant.

CamC is the easier class pax wise for sure.

How would they know if you had a diff tune?

I would know, and I don't race that way.

CAM C
 

Makes it sound like CAM C PAX is soft. Or is STU too stiff?

It is. I've never understood it in regards to CAM-C. CAM-T? Sure, I get it. CAM-S has a PAX that I would say makes sense. CAM-C should really be somewhere around 0.830.

so for reference. on a 60 secons course in STU id have to go about .8 faster than my car in BS, but only .2 faster in camC to match a BS pax time. Id say pax wise camC is a bit squishy lol

Having come from many years of running STU in an STI (typically outrunning CAMS), I don't see the Camaro being competitive unless you can get the weight to 3400 or less and use all of the tire allowance. In that case, CAMC would be easier to do than the much more restrictive STU rules. Tire:weight being most important, but power:weight coming in somewhat closely behind. Big factor being weight. Adding tire width is a good step, but removing weight from the car in an STU legal manner will not be easy. Also, will 315's on 11"+ wheels really fit up front without modifying the fenders?

I agree that weight is the biggest factor in being competitive in STU. Also, rotis was able to fit 315’s on 18x11 up front on SS stock fenders with MCS shocks that provided more inboard clearance.

https://www.camaro6.com/forums/showp...10&postcount=2

oh trust me we have been chatting. that said if its not stu competitive, camC is right there.

I think CAMC PAX is a bit soft, most likely because it is not a jacket class. If it was a Jacket class I'm sure there would be more involvement from the jacket hunters. Maybe I'll ask Tom Berry to drive my car this weekend and see how it does against our other top drivers in the region.

The CAMC index is *very* soft if you consider what is possible in the CAM rules. It's less soft if you consider the typical CAM build, which is a few hundred pounds overweight and probably not running 315 square Yoks on 12" wheels.

weren't the yoke excluded from this class?

They aren't on the excluded list now. The Kumho V720 ACR still is. And the Cup tires listed are below 200tw anyways.

ahh ok cause yeah I thought they were at one point.

Interesting you think that about CAM-C. CAM-S minimum weight is 2900 lbs vs 3300 lbs for CAM-C. And CAM-S cars are two seaters, sports cars which have lower center of gravity plus better weight distribution. If CAM-C pax was 0.830, that would be not even 0.2 sec difference from CAM-S on 60 sec course.
I would agree on CAM-T that it is soft. With minimum weight of 3000 lbs, that should be closer to STU.
STU is probably just right IMO. They are lightweight, or AWD, or mid engine. If 315 tires are allowed, I bet 0.828 pax won’t last long...
BS makes sense for modern cars that are well designed and fast out of the box.
I would be curious to hear more opinions on subject of CAM-C vs STU pax if anyone cares to comment and provide some reasoning based on tires, weight, power and allowed suspension mods.

Hi Apexit,

I am doing my first ever autocross day this coming Sunday at PPIR in CO with RMSolo.org (SCCA). I have a 2018 1SS 1LE, virtually stock. I have a lot of learning to do but was wondering what drive mode you think I should run my first session in to start my learning curve baseline?

I appreciate any advice.

Thanks.

IMO... Track mode with all nannies off / sus on sport.

I've considered doing some of the winter autoX events but our SC3 tires are horrible if it's <60F. With a high of 45 you'll need a few runs with minimal time in between to even have a hope of your car handling normally, and it'll never get close to it's full potential. To help compensate I'd try running a few psi less in rear vs front. Maybe try 35 psi front / 31-32 psi rear.

The car's handling is going to be REALLY off and totally sketchy at 45F on your 1st run, and if you go 1st it may be more like 35F, which is really below what the tires are designed for... the car is gonna plow like crazy... be careful and don't hit any walls!

I really appreciate the input Dave. I was originally just planning to go and spectate so I can learn how the event works since I have never been to an autocross event. Then I got convinced to register to drive instead since the winter series is mostly non-competitive and it would be a good time to learn.

I am honestly still contemplating whether I will drive or not for all of the reasons you mentioned.

Thanks again!

Personally i run sport throttle track suspension. My exhaust is always in track mode lol.

Reasons, track throttle is way too touchy for autocross. 80% throttle feels like 100% and that becomes an issue when braking. Sport mode is a lot more linier of a pedal feel.

Thank you very much. Looks like I have some food for thought and will be testing different modes.

I appreciate the input.

I think you have that backward. Track throttle is much more linear, it's Sport and Tour that are touchy...

I also get better results with sport sus, track may bet better for smooth surfaces but for PPIR I think sport will work better.

I also leave my exhaust on track setting all the time, lol...

Those with AX tires like RE71 will fare far better in cold temps. SC3 are going to be frustrating because the car is going to understeer horribly and it'll spin with little margin for error. PPIR has some concrete walls, courses are well designed but I have seen a car driven into a wall last year. Personally, I don't feel it's worth it unless temps are over 60F with the SC3s.