Chets LS3

Autocross in SSM
Car:
08 base Vette
Z51 bars
Pfadt joc shocks
Wider tires in front.

275/305 re-11 tire combo.
Lowered on stock bolts


During auto x today I kept swapping back and forth to a friend of mines z51 car and it seems I have a crapload more push or under steer than he does. Im running a wider and stickier tire than he is but in the corners I have way more push and therefore less traction and a lot more scrubbing going on. It can very well be driver induced. He seems to think I'm turning to hard, but I was slowing down and trying to saw the SW as much as possible throughout the day. Tire pressure was around 31-33psi in the fronts. Any ideas.

bsalie99

In SSM tires should be 315 and 335 or 345 on a C6

Chets LS3

Are you saying I'm in the wrong class? I have a base c6. 345/315 no work

Sox-Fan

What else have you done to the car to end up in SSM?

what alignment are you running?

I also run re-11, though on a c5. I'm running 34 to 35 front, 32 rear. I think 31 might be a tad low for fronts, but I suspect you have more going on than tire pressure.

c4cruiser

I would suggest a more aggressive alignment if you haven't done so already. Definitely play with tire pressure. You mentioned 31-33 psi up front but is that cold or after the first run? Are you dropping air pressures after a run or two?

How is your friend's car set up? He could have a number of things he's done that will make his car feel entirely different.

Chets LS3

I was at 35 after two runs, dropped it to 31, and i was seeing 32-33 after the runs. car has headers/intake, I believe a fairly steerable alignment is on the car (its probably time for one anyways) re-11s are down to 3/4 /32nds. when new they felt great, and the car seemed to handle a lot better. a question I had would be my front swayer size in correlation to the wider 275 tires up front? just a thought I had.

the other corvette has nothing done other than headers and z51 package. Im also running carbotech p10/8 pads which aren't really benefiting much but I didn't take them off since the HPDE and I'm going back soon.

froggy47

You need to compare alignments.

Chets LS3

thanks for the replies guys:

these tires have made it through 4 hpde days, about 10 auto crosses and a few drag strip outings and street time too.

also I will check into the alignment i was looking at some of your post froggy, but I don't think ill be tackling that myself.

Ill be autox'ing tom. and see how it turns out again.

Sox-Fan

Still not sure why you are SSM and not in SSP. But either way, sounds as though the tires are lapped out.

Chets LS3

Not sure I guess we should be in SSP. can you run a R comp in ssp if we change?

dhowdy

yes

Chets LS3

just went with some r888's a used set for now. Im running TWS next month and Im going with a diff company (chin) so they wont allow me to run an r-comp. so when these are ate up I will likely go to an r6/7.

- Im also looking into checking my alignment and getting as much neg camber as possible and going with a bigger front swaybar. (strano adj 35 mm) most likely.

as far as brake pads, what are some good suggestions I can use for autocross, my xp10/8 combo do not get hot enough on the 1-2 minutes auto-x sessions.

Sox-Fan

I'm autocrossing with Ferodo 2500. Seem to work well for me. Very very dusty if that is a factor for you.

Chets LS3

do they get up to temp pretty quick? and dust isn't an issue, do you run them on the street to? how squeaky?

Sox-Fan

My car is my daily driver. They only have squeeked when it's below 35 degrees and even at that, not very much. Usually it's the rears as they take longer to warm up. A couple of red lights makes that go away. They do get to operating temp pretty quickly. Usually by the end of the first run they are working very well. They get to temp faster than my tires.

bsalie99

I run Carbotech XP8 front and rear and have no issues with getting them up to temp. I would not road race with them but great for autox