steve40th

I have noticed many people recommend upping tire pressure for autocross. I have fairly good street tires, BFG KD's, and when I mark them with shoe polish, the sides are never worn away, making me feel like the pressure I run 33f 32r, is okay. I was looking at some photos of a recent autocross and comparing my pics of my 93(base suspension with ZO7 sway bars, QA1 shocks), in the same turn types or same turn, of a 07 ZO6, C5 with better tires wheels and an 06 Z51 C6 to see if I could see any rollover within the tire, and there was very little.
So, would I benefit by upping my pressure. I know the ZO6 and Z51 have much better suspensions (Z51 stock/stock tires and ZO6 + A6 Hoosiers), but its all I have for comaprisons.

wtknght1

Shoe polish really tells you next to nothing. You need a pyrometer to check tire temps across the surface of the tire. Once you see the temps, then you can adjust.

The reason for upping the pressures during an Auto-X is that a tire has a sweet spot pressure. If you go to a big track, where you can do lots of laps and build some heat, that will raise the pressure automatically. With an auto-X, you only run every once in a while and tires will cool off by the time you run again. If you start at the 'optium' pressure though, theoretically, the car will handle better and your lap times will be better.

Before you ask, every tire/car/driver is different so no, there's not one perfect pressure for everyone. That's what you have to find out.

steve40th

Thanks. Next time I will start about 40f 38r and go down from there.

AZ FASTEST

I'd start at 34 and 36 and go up from there.

steve40th

34Front 36 Rear?

Corvette Don

I ran normal pressure (30) frt and rear at Hallett on saturday and after about 10 mins my pressure was @35 so they will go up quite a bit

steve40th

I am running autocross for less than 50 seconds at a time. My pressure barely goes up a couple psi, even here in Hawaii.

MySR71

I had BFG KD's on my car. I had 275R17's on the front with 1 deg of negative camber, 315R17's on the rear (I don't recall the rear camber but probably around -0.75 deg). I took some tire temps and found 34 front, 33 rear worked great. These are cold pressures.

Oh yah, I have a little toe out on the front and a little bit more toe in on the rear.

steve40th

Cool, thanks.

Armycop

I'm running GSD-3's (2001 C5 MN6) and have found 38-40 rear and 36-38 fronts to be right in the "sweet spot" for autox's. Just my .02.

MySR71

No problem. I guess I should also add that my car has poly bushings, has been lowered and corner-weighted too. As such, your pressures might be a little different.