chubbymike

Hi guys, I'm so excited that I'm taking my car to autocross tomorrow again, but I need some help from those who has some knowledge in terms of setting up cars.
I have an IS 350 w/ sports pkg (dunlop tires). and no supsension mods. but i've seen people playing with tire pressures at the autocross and i know that adjusting the pressure does firm up or loosen the suspension. but what's the general rule?
what do you suggest if I want to correct understeer or oversteer?
and how many lbs. from the manufacturer's recommended tire pressure is ok?
lastly, I was told (at least from my bmw days) that the manufacturer usually sets the car toward understeer and so they recommended us to boost up the tire pressure more. is this true for Lexus also??

Thanks.

meteoro

Yes, you will need to increase the pressure some. I started with 40 PSI all around.
Now, I use a staggered set up as well. The car tends to understeer pretty bad with VDIM on. With it off it is not as bad. To make it more neutral, I went ahead and played with the air pressure. I have a 2PSI differential between the front and rear. I rund 38PSI in the front and 40PSI in the rear.

The car has tons of grip, but requires finesse to extract the most out of, if you try to manhandle it, it will just understeer like crazy. And yeah if you come in too hot for a turn, just kiss it good by, it will plow straight forward.

But once you get it right, the car is marvelous!!!!!