C3 auto cross
Instructor
Joined: Nov 2019
Posts: 182
Likes: 112
Its a blessing and a curse. All of the CAM classes are pretty open. So you can do pretty much whatever you want. But it also means, your competition can do pretty much whatever they want, and some have DEEP pockets. Plus, some are starting with C4s, C5s, or C6s and doing the same mods you are. Or, they're running a C2 or C3 with a full aftermarket frame.
Yes they are.
Whatever you can stuff in there is within the rules. Though, you do want to pay attention to what tires are available in your size. There are tires out there that are worth taking a size hit on. A 335 BFG Rival will likely be slower than a 315 Yokohama A052, for example.
Are flairs allowed?
10-11-12 inch?
Thread Starter
Instructor
Joined: May 2025
Posts: 114
Likes: 33
Installed mono ***** in trailing arms and I didn’t even think about raising the front mount because your right we did that all the time for bite in a race car.
coil overs on the rear are mounted in front of half shafts
Modified the aframe mounting location and height
Weight jacks
I’ve got most of the parts for the power steering now so when I install that box I will do a custom center link.
Old Pro Solo Guy
Joined: Dec 2017
Posts: 7,975
Likes: 4,340
From: Marlton NJ
Yep!
You have a lot of tricks in there already.
Congrats!
Being creative is fun isn't it?
So if you feel like it you could lengthen the tubular a arms, and widen the track and slow the camber curve change. It,s likely still pos camber gain, unless you made a lot of changes.
When the car rolls 2*, the camber goes pos. The camber gain on bump puts back some of that, but not all. You still wind up going pos.
Are you measuring or changing the camber gain and bump steer curves?
Parking lots are pretty flat and high traction, so stiff in roll seems to work the best, and really helps quicken response in the slaloms. But I had to soften up the bars for the wet
You have a lot of tricks in there already.
Congrats!
Being creative is fun isn't it?
So if you feel like it you could lengthen the tubular a arms, and widen the track and slow the camber curve change. It,s likely still pos camber gain, unless you made a lot of changes.
When the car rolls 2*, the camber goes pos. The camber gain on bump puts back some of that, but not all. You still wind up going pos.
Are you measuring or changing the camber gain and bump steer curves?
Parking lots are pretty flat and high traction, so stiff in roll seems to work the best, and really helps quicken response in the slaloms. But I had to soften up the bars for the wet
Last edited by leigh1322; Oct 17, 2025 at 04:45 PM.
Instructor
Joined: Jun 2023
Posts: 175
Likes: 74
From: California
Its a blessing and a curse. All of the CAM classes are pretty open. So you can do pretty much whatever you want. But it also means, your competition can do pretty much whatever they want, and some have DEEP pockets. Plus, some are starting with C4s, C5s, or C6s and doing the same mods you are. Or, they're running a C2 or C3 with a full aftermarket frame.
The only advantage of running an older Corvette in CAM-S is that anything 84 or newer has a minimum weight of 3180 vs 2680 (including driver) for the older cars.
IF you can get down in that range, you might stand a chance. I'm nowhere near that myself but there's a 800 hp Cobra around here that has to ballast to hit the 2680 weight and he'll get close to the top cars. It sounds like AZSTAR's car will be similar so that should make for a competitive car in that class.
Safety Car
Joined: Nov 2008
Posts: 3,709
Likes: 550
From: Seattle Washington
With out going totally crazy on fabrication a C4 Rear Suspension can be done without breaking the bank. Highly recommend doing this with the Body removed. But this brings up the scarcity of the C4 Dana 44. With the current C4 values being so low you can buy entire cars sometimes for less than the Dana 44 used to sell for. Couple this with some aftermarket A Arms.
Thread Starter
Instructor
Joined: May 2025
Posts: 114
Likes: 33
With out going totally crazy on fabrication a C4 Rear Suspension can be done without breaking the bank. Highly recommend doing this with the Body removed. But this brings up the scarcity of the C4 Dana 44. With the current C4 values being so low you can buy entire cars sometimes for less than the Dana 44 used to sell for. Couple this with some aftermarket A Arms.
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Race Director
Joined: May 2006
Posts: 18,626
Likes: 2,553
Thread Starter
Instructor
Joined: May 2025
Posts: 114
Likes: 33
I have been buying and using Afco for years and that’s probably where they buy them from. I can build that set for half that price and already have them on car. The reason I ask is because of the racing I did it was ok to drag the inside tire a little just wasn’t sure about corvettes.
Thread Starter
Instructor
Joined: May 2025
Posts: 114
Likes: 33
Wheels
What wheel width are you running?
You are getting deep into one of my 30 year old Pro-Solo speed secrets now.
A 275-40-18 has a suggested wheel width of 9.0 to 11.0"
For autocross use, for max traction, flatest tire tread, and least sidewall deflection, you should run the maximum wheel width possible.
In this case 11.0". And those do not fit on a C3 very easily.
At anything less than that, you get more sidewall deflection, more tire rollover, and need to band-aid it by pumping up front tire pressures, and greatly increasing negative camber. It will be near impossible to get perfectly even tread temperatures.
I have done those tests, many times.
The car would be faster, with wider wheels, or believe it or not, skinner tires on your less than optimal wheel width.
Always run a tire that is "maxed-out" on your width wheel, for maximum G-force.
Once I did that, I had to drop my camber settings by over 1 degree, to 0.75*, to even out the tire temps. Then I had to lower my tire psis from the 40s down to 24psi. Again to even out the tire tread temps.
Then, and only then, for the first time I got perfectly even tire temps, with zero tread roll-over. Then the g-force jumped from 1.1 to 1.29G
I had 245-40-16s on a 10.0" wide wheel, jumping up from an 8.0" wide wheel. And the exact same set of worn tires. "0" Treadwear Yoko A008-Rs
And they only recommended up to a 9.5" wide rim! You need to stretch those sidewalls tight.
This was way back in the 90s, and such skid pad numbers were highly unusual.
Most other drivers did not agree with my setup, but the science of the tire temps told me to do this, and the G-force responded, and BTW, I was beating them.
Oh and those wide wheels took out 2" of slop in my steering wheel as well! It was like a 1/4" movement/surgeon's scalpel after that. That helped my confidence a lot. IIRC my 60 sec course times dropped a lot, like .75sec. And the car was so much more predictable at the sliding limit, I could feel the edge of adhesion and it's drop-off much better.
We did the same thing on some other cars from Mustangs to Civics, where the factory tires were too big for the wheels, and put smaller tires on them, and the cars went faster.
You are getting deep into one of my 30 year old Pro-Solo speed secrets now.
A 275-40-18 has a suggested wheel width of 9.0 to 11.0"
For autocross use, for max traction, flatest tire tread, and least sidewall deflection, you should run the maximum wheel width possible.
In this case 11.0". And those do not fit on a C3 very easily.
At anything less than that, you get more sidewall deflection, more tire rollover, and need to band-aid it by pumping up front tire pressures, and greatly increasing negative camber. It will be near impossible to get perfectly even tread temperatures.
I have done those tests, many times.
The car would be faster, with wider wheels, or believe it or not, skinner tires on your less than optimal wheel width.
Always run a tire that is "maxed-out" on your width wheel, for maximum G-force.
Once I did that, I had to drop my camber settings by over 1 degree, to 0.75*, to even out the tire temps. Then I had to lower my tire psis from the 40s down to 24psi. Again to even out the tire tread temps.
Then, and only then, for the first time I got perfectly even tire temps, with zero tread roll-over. Then the g-force jumped from 1.1 to 1.29G
I had 245-40-16s on a 10.0" wide wheel, jumping up from an 8.0" wide wheel. And the exact same set of worn tires. "0" Treadwear Yoko A008-Rs
And they only recommended up to a 9.5" wide rim! You need to stretch those sidewalls tight.
This was way back in the 90s, and such skid pad numbers were highly unusual.
Most other drivers did not agree with my setup, but the science of the tire temps told me to do this, and the G-force responded, and BTW, I was beating them.
Oh and those wide wheels took out 2" of slop in my steering wheel as well! It was like a 1/4" movement/surgeon's scalpel after that. That helped my confidence a lot. IIRC my 60 sec course times dropped a lot, like .75sec. And the car was so much more predictable at the sliding limit, I could feel the edge of adhesion and it's drop-off much better.
We did the same thing on some other cars from Mustangs to Civics, where the factory tires were too big for the wheels, and put smaller tires on them, and the cars went faster.
bridgestone potenza RE-71RS 200AA.
