Track issues at 7/10ths?

[mbintx]

I'm signed up for a local charity track event in December, and thought I'd bring my 135i to see how it feels on a track. This event will be pretty crowded, and I expect a wide range of vehicles and driver skill levels at this event. Ergo, this will NOT be a balls-to-the-wall event and there will be no opportunity--or need--to push really hard. Having said all that, should I expect any issues with the 135i if I'm driving it at 7/10ths, give or take? I know my limits, but not those of the Bimmer.

For perspective, I'm quite familiar with the track and I own a track-prepped supercharged Miata that is my dedicated track toy. Lots of track time under my belt, including 24 Hours of Lemons.

[pixelblue]

you will be fine. the car will be rolling and understeering a lot if pushed hard. it will be a stark contrast to your track prepped miata but you should still have a lot of fun pulling out of tight corners with all that torque

[DriveHard]

Originally Posted by mbintx

I'm signed up for a local charity track event in December, and thought I'd bring my 135i to see how it feels on a track. This event will be pretty crowded, and I expect a wide range of vehicles and driver skill levels at this event. Ergo, this will NOT be a balls-to-the-wall event and there will be no opportunity--or need--to push really hard. Having said all that, should I expect any issues with the 135i if I'm driving it at 7/10ths, give or take? I know my limits, but not those of the Bimmer.

For perspective, I'm quite familiar with the track and I own a track-prepped supercharged Miata that is my dedicated track toy. Lots of track time under my belt, including 24 Hours of Lemons.

I guess if you on RFT's ( Run Flats ) just adjust the pressure accordingly so you dont scallop them ( or risk scalloping them) since they would be your daily tires.

Other than that, have at it..

being that you are already a track junkie, you already know all the little rules.. no loose objects, no fluid loss, all cap tights, torque your lug nuts ..

have fun..

p.s. you may want to twist your lap belt once or twice befor clicking it in so your not so sloppy in the seat. the leather is slippery.

[JimD]

I messed around with cold tire pressure to find what would keep my tires on the treads (as opposed to the sidewalls) in an autocross. I decided 40/40 was about right for my 128i w/sport. I'm guessing it should be at least a good starting point for a 135i.

I've driven a M3, M5, and M6 on the same track I've driven my 128i on and I don't think my admittedly slower bimmer is all that different. Understeer was only bad if I went in too fast into a really tight corner. Usually I could change from under to over steer with the throttle in all these cars, mine included

Jim

[mbintx]

I've got the BMW Performance suspension, so I hope that will help with the pitch and wallow a little bit. No run-flats, either. It's got the Hankooks that seem to be quite popular with the 1 crowd. Good heads-up on the 40 psi; I was thinking more like 36-37 psi cold.
I'm pretty easy on tires. Mostly worried about brakes holding up, since there a couple of long straights followed by 90 or 180 deg. corners.

[GaryS]

Originally Posted by mbintx

Mostly worried about brakes holding up, since there a couple of long straights followed by 90 or 180 deg. corners.

If you brake hard three or four consecutive laps, the stock pads will start fading for sure. So you let up for a lap.

[JimD]

I've only done autocrosses in my 128i vert. BMWCCA won't let convertibles participate in driving events. Max speed in my autocrosses was 60-70 mph. I noticed no fade. We did as many as 5 laps before coming off. This was on the BMW Performance Center track - with cones out to cut speed.

I also didn't notice any fade when I did M school in M3s, M5s, and M6s. We only tracked the M3s and M6s (M5s were used on wet skidpad exercises). Ms are different but I assume they had stock pads. We used the same track with less cones - max speed was about 100 mph.

I thought I was running hard in all these cases but my times were mid-pack to slower. The cooling fan did not even come on for the engine in the autorcrosses which have been in November. Car seemed to say "so what".

Jim