BostonDMD

But this past week-end when I left the PSM on in my CaymanS, I just was not allowed to throttle steer to rotate the car, drift or just go to the power early without it kicking in repeatedly ……… of course when I shut it off then the car behaved beautifully……..

I can see how PSM would help with driver’s (and its instructor) preservation (safety), I mean with it on I think it is basically impossible to even have an accidental spin it is so controlling, yet still makes the driver look fast……… BUT.....my question is:

What does PSM really do for driver’s development (learning) past the beginners level?

Are car controls skills obsolete anymore with the advent of PSM or other traction control devices?

Disclaimer: the track I attended was more like a giant autocross course, with lots of quick turns.....

Larry Herman

Was it really that invasive? Could it have been the tracftion control kicking in when you got on the power? Without an LSD, you have to be really progressive about feeding in the throttle in tight turns. Just a thought.

Veloce Raptor

My thought too, Larry

quickxotica

I tracked a 2007 Cayman S for 2 years and experienced the same thing. The car just wouldn't respond to mid-corner throttle adjustments they way you'd want it to (or the way it does with PSM off). I preferred driving with it off at the track once I got comfortable with the car. If you fight against the PSM, it just drags the rear brakes to keep you pointed straight (thereby ensuring that when you leave the track at least it will be nose-first rather than ***-first... see how safe that is?)

Having said all that, driving with PSM on, as long as you are smooth everywhere you can avoid most of PSM's perceptible interventions and still go very, very fast around a track.

IcemanG17

My typical track cars do not have any type of traction control...or even ABS...

However my 2008 M3 had a 3 level traction control....I never drove on track in full traction control mode or with it off, only in "M" mode which was the sport setting......I found that it would intervene, sometimes heavily only when I was doing something kinda dumb....typically it would reduce throttle in hard accelerating low speed corners....so it might have saved a power oversteer scenario?

I did see it blink occasionally in some high speed corners, but I didn't "feel" it....

The one thing I learned is it wants you to be SMOOTH.....which is always the goal.....I'd say its a very good thing for new students, especially in powerful cars!

multi21

PSM has nothing to do with driver development. It has to do with liability and lawyers. It's a nanny for the nanny state, nothing more and nothing less. Don't view it as a lack of your driving skills or that you're necessarily doing something wrong.

racer

x2 above.. PSM (stability control) is a requirement for all new cars in the US. It is designed to keep the car under control because it has to assume the driver doesn't know what he/she is doing and must therefor preserve all involved. You might change your driving style to reduce its interference, but if you learned to "throttle" steer a car, well, PSM is NOT your friend.

Matt Romanowski

Here's my take without riding with you (but Jay did and said you were hauling):

To be fast at NHMS, you have to slide the car a lot. PSM doesn't like this. For beginners, they should be able to drive without having the PSM come on, but by the time they are advanced yellow, it will come in in turn 3. By the time they are in black, it's probably on in most corners some amount.

I bet you had it flash on a little in turn 1 when the car bounced in entry, then came on some for turn 2a. It probably came on a few times in turn 2b when you nailed it. Then, it was on just after turn in at turn 3. Definately on by the time you hit the rumble strip in the middle of turn 3. It might have been on some in turn 6 (the bowl) if you were getting the car to rotate (read carrying enough entry speed). Then it probably came on a few times exiting turn 10 if you carried too much speed down the hill. Finally, if you did EFK right, it came on in the middle of the left onto the front straight.

How did I do?

BostonDMD

That is exactly what happened.......how did you know that?

BTW, thanks for the pointers on Friday......

Matt Romanowski

Super Instructor Powers. Or I've spent a lot of time in PSM cars around that track and they all do the same thing when you start driving faster. Try doing it in an early Boxster. PSM KILLS turn 3.

No problem on the pointers. I hope to see you in an instructor meeting soon...

cgomez

From my experience, PSM significantly intervenes and slows you down significantly (the more powerful the car, the more time you loose) and spoils the driving experience in a P-Car if you are driving at 10/10ths.

If you keep it below 9/10ths with NO trail-braking rotation, controlled 4 wheel, or slight power-on oversteer, then is irrelevant whether you have PSM on or off.

IMO, the Porsche PSM is a SAFETY device and not a performance oriented device. PSM off is always faster. Other cars (Lotus adjustable TC, Newer Ferraris adjustable TC that works in coordination with e-Diff, etc.) do have devices that indeed might improve performance.

Although I totally dislike Traction or Stability control on a car at the track, on the other hand, i strongly endorse ABS, as it is impossible to modulate the brakes (independently) as ABS does, and the consequences of any lockup can be catastrophic and expensive (Trailbraking rear lockup ends up in a nasty spin most of the time without ABS, while with ABS you just run wide - slower off line - but can still rim-shot a corner safely after a mistake)

Land Jet

I don't know about the Cayman but in my car you can unplug it and still leave the ABS intact. I'm not talking turned off because it will still function in a less intrusive way, I mean unplugged. The connection is up at the master cylinder.

924RACR

Don't forget, in having these discussions, that not all PSM, and particularly not all ESC (stability control) systems are the same. The same basic systems can and are tuned to have vastly different performance in different vehicles, sometimes even across different model years. So, unless you're comparing, say, a stock '09 Cayman S to a stock '09 Cayman S, don't expect the same inputs or conditions to produce the same performance.

cgomez has hinted at this; I'm pointing out that it isn't even the same within one manufacturer or car line.

I'd also like to point out that ESC generally does not tolerate significant countersteering. Some will tolerate only a small amount, some a lot... but when you're trying to slide the car - you likely will be able to do more if you can avoid countersteering. This would be perceived by the driver as being smoother, of course.

Matt Romanowski

I could be wrong, but it's not the actual countersteering that matters, it's the yaw of the car. The vehicle has yaw sensors that pick up the slip angle and then it intervenes. This makes it so the car can save itself when an inexperienced driver gets it sideways and doesn't do anything to save themselves.

2BWise

Its both. It uses yaw rate and steering angle. You've got half the equation right, but left out the steering. If it sees a yaw rate overshoot and a steering correction, so steering and yaw in opposite directions you will get an intervention as it knows the driver is trying to correct a slide. It can do the opposite if you're understeering and help the driver turn the car too.