Quote:
Originally Posted by TajoMan
How was RE71?
I heard that the sidewall is very stiff and I prefer stiff side wall for auto x.
Stock MPSS was like a jelly at 48 psi in front. lol
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RE-71Rs (and Rival S 1.5) are one of the best, legal street tires you can get that's still reasonable in price (unlike Sport Cups). There's a reason why many people run these tires at national level events.
Your pressures are WAY too high. You need to be in the mid 30s if you want grip. Given that these tires have stiff sidewall, you don't need to run as high of pressure.
Quote:
Originally Posted by TajoMan
I guess it's my poor driving too. 
I used to put 50 psi in front when I auto x my 07 GTI. lol
Tire does not heat up that much during auto x. You run for 1 minute and wait for 5~10 min.
The pressure goes up maybe 3~4 psi.
and of course, I lower it down to 35 psi for street use. |
Tires definitely heat up (although not as much as a track session) and it's a little more than 3-4 psi if you're pushing the car enough and the tires are sticky. The interval between your runs varies by club, but you actually need to be constantly checking/adjusting your pressure before/after each run until about your 4th run or so.
Get some chalk and mark your tires from the edge of shoulder tread block to the sidewall, so you can see how much rollover you're getting (will vary based on tires, camber, psi, etc). Then find the tread marker on the sidewall of the tire to see where the rollover needs to stop ideally. From there, you just adjust tire pressure and camber as appropriate. Having a pyrometer helps but I wouldn't worry about that now. Of course, if you don't have enough seat time, none of this should be your primary concern, but that's another point.
BTW, for FWD, you want more pressure in the rear so you can get the rear to rotate easier. By adding pressure (and that much at that) to the front, all you're doing is introducing more understeer.
No offense, but I think you need to start making friends at your local autocross who is national level or very competitive locally, because I get the feeling you're doing things without proper guidance or someone's feeding you bad advice.
What clubs are you racing with in Chicago?