Hi All,
I have a set of hoosiers 245/40/18 in front, and 275/35/18 in the rear. Does anyone have tire pressure recomendations for use on the track? At least for a starting point? These will be on a 2005 M3 Coupe. Stock suspension, Hoosier R-Compound tires, and Cool Willy track brake pads.

Thanks People!

<TABLE id=HB_Mail_Container height="100%" cellSpacing=0 cellPadding=0 width="100%" border=0 UNSELECTABLE="on"><TBODY><TR height="100%" width="100%" UNSELECTABLE="on"><TD id=HB_Focus_Element vAlign=top width="100%" background="" height=250 UNSELECTABLE="off">well it depends. on our 996 race cars we run hoosier R6s, we see full temp in 5-6 laps depending on the circuit and the cars weigh 3200lbs. we run nitrogen so our pressure increase is consistent. depending on your driving and your track speed i would shoot for 38psi hot. hot being in the 190-210 range. as for cold. we set up on a 65deg morning at 28 and bleed if we have to as the days heat builds up. we also run tirewarmers, if you plan on running something like that i can set you up with even more data. consider picking up a digital pyrometer (probe style) so you can tune your alignment aswell. dont hesitate to pm me once you have a data set and i can help you get your alignment squared away :)
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thanks PeeJ. That helps as a starting point to at least get me going in the right direction. I do have a pyrometer, and this will be the first time using it, and the tires/car combination. Alignment settings are stock right now with very little wiggle room for camber/caster. My car weighs approx 3500 lbs (according to the owners manual). I'll let you know what I come up with for temps and hot pressure. Thanks again.

well due to stock suspension, and having some brake fade, I was not able to really push the car past lets say 7/10ths, or 8/10ths. My tires were a used set of Hoosiers (bought them more for the wheels they were mounted on), which still had a significant amount of tread depth when I started, as well as even wear across the face of the tire. Due to the stock suspension (body roll, and camber settings) I ended up cording my front tires after my first session on the outside of tires. I started at 32psi cold, which resulted in about 38psi when I pulled into the paddock. I'm sure there was some cooling down on the cool-down lap figured into this as well. I ended up increasing to 34psi cold to give about 40psi hot to sort of help keep the tire from rolling over onto the edge, just so I could finish out the day tip-toeing around the track.

All in all, I don't really have good data due to:
1) I was not going very fast on my first session because it was my second trackday in about 5 yrs (very rusty skills), with a new car, new brake pads, new (to me) tires. I just wanted to get the feel of things again for the first time out.
2) I was tip-toeing around the track in later sessions due to no confidence in corded tires, and fading brakes
3) Temps and pressures were taken after a cool-down lap. I didn't bother taking pit lane temps after a hot lap due to the fact that I wasn't pushing the car to obtain accurate temp/pressure data.

Now I'm debating whether its even worth it for me to buy another set of r-compound tires until after I get some shocks/springs/sways/camber plates. I'm probably going to get the suspension anyways, so there's probably no sense in throwing $$$$ in for some expensive tires when I'm just going to burn through the outside edge after 1 or 2 days.

I now have other financial responsibilities which make it difficult/unwise for me to just dump cash into track parts on my car. Not quite like when I was an engineer, and still living at home with mom and dad years ago, with enough disposable income to fund my track habits. Ah.......the good ole days.

hrmm. im not entirely familiar with the stock setup of the e46m. not so sure what stock spring rates are. what i would suggest before your next track day is to invest in sway bars or springs before going crazy. i believe whats happening (besides a lack of camber) is that as the suspension compresses and the chassis loads, the car rolls excessively. due to the R compound tires the situations only made worse because theres more overall grip. the excessive body roll effectively decreases your camber (could go as far as pos camber) as your car is loaded around corner. sway bars might be your least expensive remedy for the lack of camber issue before going to camber plates.

anyone more familiar with the e46 feel free to chime in!