01badvette

Hello all,
This will be my 2nd year doing AutoX and running my 01 Vette in CAM-S. I was able to win my region last year along with several other smaller events but I'm in need of some upgrades to compete at higher level venues. 95% of the events I run are smaller parking lot style courses 30-40sec runs. Last year I ran stock sizes and offset RE71R's for tires and this year looking to go to a wider square set up. I'm looking at going to 285/30R18s RE71Rs setup, but am wondering what I will be sacrificing from the popular 315/30R18 Rival S I see a lot of guys running. I know the wider contact patch will help but as far as compound will the RE71Rs be able to make up the ground on the smaller courses? Suspension wise I have C5 Z06 mono springs and sways and C6 Z06 shocks. I don't have the funds for coil overs but am wondering if something like the Johnny O'Connell sways and shocks would be a substantial upgrade? Also will be curious to see what type of alignments I can do with the square setup on stock adjusters.
I've seen several threads here and there with information like this in it I'm just looking for some solid answers in terms of direction as I don't have the funds to be changing setups half way thru the season.

v10climber

The reason people run the 315 Rival S is because it pairs nicely with the 335 Rival S and is really the only option for bigger tires (necessitates an 18" wheel). I think the 315 square Rivals S vs 285 square Bridgestone might not actually be that much different. What size wheels are you going to put them on?

I'm not sure the JOC stuff will be a massive upgrade. The stock corvette suspension is pretty good and honestly if this is only your 2nd year there are probably still large improvements to be made to the driver if you spent some money on more seat time or schools. If you wanted to do something a large front bar like one Sam Strano sells would be a big improvement for not much money. And it would work just fine with your square tire setup. And you could keep it going forward if you ended up moving to stiffer springs or a coilover setup.

For alignment stuff max out your front camber and run the rear maybe a degree less than the front. little bit of toe in at the rear and zero toe or a little out at the front. Although, the tire setup isn't going to affect your alignment. If you can only get -2.5 degrees now in the front changing the front wheel/tire setup isn't going to affect that.

01badvette

I'm planning on using the 285's on oem 5 spoke speedlines 18x9.5s. My driving abilities can def. improve my last 5 events of the season I was in the top 10 fastest raw times for every event but I still have alot of time left on the table watching the videos. With the current setup the car just feels very loose thru the center of the corners I'd like to find something to give me more of a planted feeling mid corner.

v10climber

Those wheels are barely wide enough to support the 285 Bridgestones much less the 315 Rival S. You'll want to stick with the 285 Bridgestones for sure. When you say mid-corner you mean steady state cornering right? Like if you had access to a skidpad and did a big circle the car would be biased towards oversteer? Try more rear camber. Since you don't have adjustable swaybars/shocks the alignment, ride height, and tire pressure is about all you can fiddle with.

01badvette

Correct biased towards over steer, entering and exit I have a good set feeling in the corners it's just steady state cornering where the car seems numb to me in terms of feeling the limits. If I go with the 315s I would get some 18x10.5s, Bridgestone says the 9.5 will be perfect for the 285s

v10climber

If there was one place you can throw manufacturer recommendations out the window it's rim size recommendations. I run a 285 (class limit in STU) on a 10.5 and would run them on an 11 if I was buying new wheels. The 315 needs like an 11 or 11.5. Honestly if you're going to get new wheels you'd want at least 18x12 and run the 335 rival s in the rear. The 335 might fit up front if you get creative but an 18x11 with a 315 Rival s up front shouldn't be hard at all.

l98tpi

Here is my quick analysis on the RE71R vs Rival S. I chose to go with the 285 RE71R since I had to pay for new 18 wheels too and I wanted to keep the weight to a minimum. On my C4 I had always ran 17" wheels and 315's square (Hoosiers ). With the allowance of C4 and newer Vettes into CAMS for 2016, I had to find the competitive 200 tw tire, so it was limited to RE71Rs or the Rival S.

The RE71R was a nice tire and handled very good in the wet. They heated up quick and were easy to read. But when it was hot outside; it was a battle to keep them under 150degrees. Over 150degrees and they suck.

We were the only car in CAM S at Nationals to run RE71R's. Day 2 at Nationals it rained hard and the course was wet. At the end of 2nd runs, my co driver had the fastest time if not the 2nd quickest. But the course started to dry up and we lost a lot of time compared to the others after the third runs were finished.

One other thing I recently came across was a statement that the RE71R was not as good of a fit for a high sprung car (high spring rates). So, with all this I would go with the Rival S's for the Corvette. On Subaru's and Mitsu's and Hondas the RE71R is a great tire but not as much for the Vette.

boony1968

Being one season in, I'd say stick with what you've got OTHER THAN - get a Stranobar and make sure your alignment is solid. Work on seat time and try to hit some bigger events this year. You have a I & II Evoschool school coming your way (Rochester) in a few months that would be worthwhile.

You'll find mixed options on coilovers. I do know that the guys that spend the cash say they love them, but I haven't seen evidence of them making for faster runs. Take a look at AS times at national events - most of the top guys are running Koni singles, stock springs, Stranobar and Rival-S's or RE71's - that's it. IMO, if (in Cam-S) you're not raw timing proven drivers in AS the driver still has the most room for improvement. Check into the evoschool.

01badvette

I think for this year I will go with the Strano bar I contacted them in terms of solid or hollow bar and either the 275/35 or 285/30 RE71Rs square setup on my 9.5' wheels. I currently have the C5 z06 front sway and C6 Z51 rear sway.
Any input on upgrading the rear bar as well to the Strano adjustable?



I think seat time will be a big factor this year, last year I ran 12 events and at the end of the season was usually posting in the top 3 fastest raw times of anyone/any class on street tires and made drastic jumps in terms of ability but I still have a long way to go, I might do the EVO school I see one in Rochester, New Jersey and I think one in CT.

v10climber

Sam is often working remotely because he's working with vendors or doing events so the response might not be right away. But he's one of the best corvette set up guys in the country especially for auto-x. Pretty much every fast AS/BS/SSR car he's helped set up and they're running his front bars. My understanding is that his rear bar is more of a tuning aid. I believe on the middle setting it's equivalent to a C5 Z51 rear bar but his is adjustable so you can actually make changes depending on setup. I don't think it's necessary right away but if you need to continue to tweak balance it's a great option later on.

strano@stranoparts.com

Sorry guys. I've been traveling and then there was some snafu here with my account. I glanced at this but mostly just wanted to get an answer down here.

First, grip matters. Tire size matters. No way would I opt to run a 285 RE71R if a 305 is an option, or Rival S in a 315 or 335. My old C5 FRC on 10.5" wheels with 285's behaved in ways more like a Z06 (BTW, this is now V10climber's car) because of a relative lack of traction making it behave like it has more power and deeper gearing. We were stuck on that then because of what was available and the tire limit in STU for a Corvette. And what you do with wheels and tires plays into what you do with the other stuff, as those things change balance and traction.

My front bars are pretty much the standard in all the classes the C5/C6 is winning. Very, very few not on by bars. The rear bar is not as commonly used as it's really only relevant for cars that can change both by rule (not any AS/BS/SSR car). I stand by my rear bar and it's sizing when it's used in combination that is fitting (correct front, springs that aren't nuts, etc). I don't feel the car wants or needs a BIG rear bar. It's there for a trim change. Ideally we want the rear bar set middle most of the time to allow a tweak up or down to dial in to a surface.