First Event. Car came with 235/18 & 285/18 Dunlop Super Sports. I have a pyrometer.

Thought I would start with 36-38 FRT 40-42 Rear.

Any suggestions?

Thanks Steve

 

You're going to understeer. Try 40 front, 39 rear. Get someone to take temps
immediately as you exit the course. They call them out, you write them down.
You may find the tires get sticky then get loose if they're too hot. Bleed aire
to keep the same pressure at the start of each run.
It sounds like you have no time for serious fiddling, but if you want to stick,
you need about 2-2.5 deg negative camber in front and a half degree less
in back.
*TURN OFF PSM*. For autocross it will intterupt unnecessarily. The car
will feel *much* more intuitive with it off. Use your AWD. Get on the power
coming out of corners.
Have fun.
Joe

 

Thanks Joe. Can you get 2+ neg camber on the front with stock suspension. I have 1 degree now and 2.5 neg in the rear per the prior owner.

Car is lowered using X73 suspension and I have the GT3 bar on the back.

Thanks Steve

 

Ok, cool. Typical other things to get the front to stick include full soft on the front
sway bar, and soft rebound damping there too. Call Kumho and ask them when
they will produce 710s in all the 700 sizes. More voices the better I hope.
I have 9" front and 12" rear wheels, and run 265 and 305 700s, but would
want 710s. If I had the bux to play right now, I'd see if I could fit 17" wheels
which would run 710s in similar wide tires.
AWD needs tires that are very close in rolling diameter. For autocross, if you
have a choice, getting the front a tiny bit taller puts more torque to the fronts
and helps pull-through in the corners, but it effectively over-biases the brakes to
the rear at the limit because ABS thinks the fronts are slower....
Joe

 

Steve:

I ran the Dunlop SSR on plenty of autocrosses at the end of last year. It's a good street tire, average track tire, and average autocross tire.

For autocross: 235/35R18 and 285/30R18 V710 (first option)
245/40R18 and 305/30R18 A3S04 2nd
245/40R18 and 305/30R18 R3S04 3rd
265/35R18 and 305/30R18 V700 4th
Dunlop SSR 5th

I run 265/35 and 285/30 SSR right now. That size won't work on AWD. You can run 245/35 and 285/30 SSR or 235/40 and 285/30.

Pressure, 32 psi hot square. Set the rear sway to full stiff. The AWD understeers badly. If shocks are adjustable on the X73, set the front ones soft and rear ones stiff. Don't bother about oversteer because the AWD will transfer power to the front on those conditions.

My car runs -3.5 front and -2.5 rear camber.

 

I would say 2-3 psi lower in the rear than front. If you really want to make it rotate, try 45 front and about 35-36 rear. I know it sounds a bit scary, but it works fairly well.