I drove my new CS in its first track event at a local track for me, Thunderhill Park Raceway. The event was sponsored by (ahem) the Golden Gate Chapter of the BMW Club, but they allow other manufacturer‘s cars at its event. Thunderhill is a track I know quite well from both racing and doing track days on motorcycles over the past dozen years. Driving a car on a track is a new adventure for me.

I made the decision to switch from tracking motorcycles (past sixteen years) to cars for both safety reasons and a deep down desire to run cars on a track. After doing quite a bit of reading on possible cars to track that were in my price range, I settled on purchasing a new CS. As others of you know that track your Caymans (chronicled in this site), I could not be more pleased with the experience. While the power doesn’t equal that of today’s modern liter class motorcycles, the CS still delivers a lot of oomph. The shifting and steering is precise and the throttle response is easily manageable in and out of corners. I only had one instance of oversteer coming out of turn four and heading up into the cyclone (for those of you that know the track), where I was a little aggressive with the foot application before getting the car turned straight and heading up the steep hill. I recovered easily and predictably, so there was really no drama at all.

I chose to keep on the stock Bridgestone shod tires for this first time event. I did no modifications to the suspension either. Based on previous posts, I kept a record of my off track PSI and kept making adjustments in an attempt to ‘kiss’ the wear-line indicators on the tire sidewalls. I continually ran too much pressure, when making adjustments down to 40 psi on hot tires. When I moved finally moved down to 38 psi hot, I hit the tops of the wear indicators on the front tires, but still not the rears. I’ll have to keep searching for the ‘right’ hot pressure for the rear tires. That could all change again when I move to R compound tires.

I made a conscious decision to turn on PASM for each session. However, one of the sessions, I simply forgot to engage PASM. I have to tell you that my experience was still great without PASM. I didn’t even realize it wasn’t on until the session was over. I experimented leaving the PSM on and turning it off over several of the sessions. Once again, I really can’t report any real differences. I tried to drive as fast as I could, but to also be smooth. Under these conditions, PSM did not seem to be a factor. I’ll be interested in hearing other’s experience with PASM and PSM both on and off during track conditions.

I plan to pick up an extra set of wheels so that I can mount some R rated tires before my next event. I just purchased a set of Michelin Pilot Cup tires. If it’s possible to get good 19” track wheels for around $1,500 for the set, I would love to hear those opinions, as well. Most of what I’ve found in that price range comes from companies in which I’ve never heard. That price would meet my budget (for right now) and keep me from having to make changes back and forth on my stock wheels and tires (19” Sport Design Wheels).

I’m attending the PCA event at Laguna Seca on Sunday September 7. If any of you members are there, please stop by and say hello.

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'08 CS
'07 BMW R1200RT

Glad you had a great time with the car. I'm pretty new to track driving as well (started last year with my Cayman S) and am thoroughly hooked on it. The track definitely felt different with the new pavement and burms (event details in the lap times database - Brian Ty - 2:13.5).

I also drove with PSM off for the first time this past weekend, and at first I didn't feel any difference, but noticed after the second day that I could point the car a little more easily on Turn 2 with some throttle adjustments.

I'll prolly do a couple more events before the year is over, but not sure which ones. i wrote a small web app that helps my buddies and I keep track of upcoming events. send me a pm if you're interested.

cheers.
-B

The wear indicators are, at best, only a rough indicator of the best pressure. Almost all street tires I have had on track were best somewhere in the 36-42 range, at operating temps, although I have no experience with this specific Bridgestone. I would suggest knocking them up and down a couple of pounds at a time from where you are now, which should get you in the ballpark quickly, based on the balance you want, and their grip.

Yup, I'll play around a bit more with the pressure at the event at Laguna Seca in early Sept.

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'08 CS
'07 BMW R1200RT

It sounds like you a good time, I hope it all continues.

I have Bridgestones as weell that I used couple of times at the track and was able to get down to 36 psi hot; there was much more grip than I had imagined.

I tend to focus first on the front tires; once I find the pressures that work well for me, adjusting rear pressures, for me, just a matter of how I want the car to handle; more loose or tight, I don't worry about getting to absolute minimum hot pressures.

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FT

The stock settings recommend a 15% psi increase in the rear tires. I kept trying to use that as an indicator for adjusting the hot pressure from front to rear and I now believe that's why I never got the rear tires set just right.

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'08 CS
'07 BMW R1200RT

I do not like much oversteer and at the track I generally end up with same front and rear hot pressures, or less than 1 psi difference with rears being higher. During an autox, I generally end up with 2 to 2.5 psi higher with the rears.

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FT

Hi!
I have heard that there could be engine problems if u fit R-tracks, anyone?

Great to hear you had a good time on the track with your car.

If you're thinking about another set of wheels for the track, you might want to get a set in 18" diameter instead of 19" - there's a much better selection of R-compound tires in 18" size and the Sport Cups are much more expensive for a set of 19s than 18s -$1200 vs. $1500 for a set.

I'm running with CDS in Friday at Laguna, but unfortunately, not staying for Sunday.

brad

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21-year PCA Member
PCA DE Instructor

It sounds like you had a great experience. I'm not familiar enough with my CS to even consider this yet. One note about PASM. Even if left in the "normal" position it still responds to aggressive driving by stiffening the suspension. This is perhaps why you did not notice a lot of difference between the two settings.