Frazier5

You will end up in the low 30's PSI front & rear by the time you are done with your runs. But it really depends on what feels good to you. Start high and go low.

RED MX5

If you don't have a pyrometer, chalk will do. I started at 32 PSI cold and worked from there based on pyrometer readings. Still running less than 40 PSI hot.

clawhammer

I run 36 psi in the front and 32 psi in the rear. I also chalk the tires to check how much I'm using.

__redruM

I posted because there was one other opinion and I was curions about why 40psi was good for autocross. I was certainly willing to admit in my post that I knew little about the subject of autocross. Thanks for both helping to clear things up and acting like a bitch both in the same post.

JGard

yeah, chalk is the most common method I've seen used.

At my first AutoX I ran 40f and 34r, fearing the snap oversteer these cars are known for.

Next event I'll be around 42/38 or so, as the car's ass still slid around quite a bit.

RED MX5

[QUOTE=__redruM,Jul 12 2007, 05:23 PM]I posted because there was one other opinion and I was curions about why 40psi was good for autocross.

GTI 20v

You always have the option of NOT posting, which, if you have no idea what you are talking about, is generally the best route. Instead, you made two factually incorrect posts which, if the rest of us hadn't chimed in, would have left the OP doing the wrong thing on race day.

You didn't ask why 40 psi was good. In fact you didn't ask a single question at all. You were trying to answer questions...incorrectly.

In my book, the bitch is the one who pretends to know things he doesn't, not the one who calls that person out.

__redruM

I NEVER pretended to KNOW what what the absolute right presure for autocross. I gave my GUESS and the REASONING behind it. All with the disclaimer that I have never experimented with tire presure at autocross. And I invited someone with more experience to correct where I was wrong.

This is what people do on forums. They discuss TOPICS. I wished to participate in the discussion. And so I did. If you want to decided who can and cannot post in topics, go start you own damn forum.

GTI 20v

You're right. When someone asks a technical question, we should all just guess at an answer, whether we know anything about the topic or not. That will definitely improve the helpfulness of the forum!

You need to recognise the difference between someone asking for opinions, and someone asking for technical answers. Because it's a big one.

5SAY307

40psi seems reasonable, AutoX runs are less than a min. You want to get tire temp up ASAP.
It all depend on race courses, track condition, car setup, and driver prefference. I like more psi in rear than front for RWD cars. The rear seems to rotate thru corner alot better and the front not choppy and understeer.
just my 2cents