Renn 951

PSM = (NOT!) PASM

ADias

I think he meant PSM - as he refers to spinning... and firm shocks (PASM has special PASM shocks).

RonCT

How is that? PSM doesn't get involved whether it's on or off. If turning it off causes you to spin, you should take your car to the dealer to get the system checked out. Is it that if you turn it off, the car does something dramatic, like apply ABS to a wheel, causing the spin?

MarcBC

I have only had my 997S a month, but I thought PSM was something like traction control. Switching it off, will allow full power to the wheels, whatever the surface. Thereby allowing spin in the wrong power / grip situation.

PASM is the suspension setting.

No?

RonCT

Basically yes - PSM is stability control - not just traction. So if for some reason you want to lay rubber, you can turn PSM off and spin the tires. But what PaulSpeed appears to be saying is on the track if you turn PSM off, you will spin-out, which makes no sense to me unless there is something mechanically wrong with the car to cause that.

I've only got about 4k miles on my 997S with about 15 hours at Lime Rock and Watkins Glen and PSM has never gotten involved unless I was trying to see if it was even operational. I've never lost traction due to too much wheel spin - it's just not possible to lose traction on the track with those monster 295s on the back. We aren't talking casual driving either - 1:03s at LRP and 2:17s at WGI bone stock with PS2s as I'm learning the car.

Mussl Kar

On some cars you can turn traction control off but it will not go away entirely. (Mercedes) You can spin your tires but if the car starts to skid it will activate and try to sort the car out. Is this also true for Pcars?

RonCT

The manual tells all... on the 997 you can turn PSM off, but if ABS kicks in on 2 wheels, it turns back on (3 wheels if you have Sport Chrono, but don't start me on this point - it's no advantage to have the elevated limit because PSM never kicks in if you are driving properly / smoothly).

mglobe

To date this has been my experience as well. I've yet to have PSM kick in on the track when I was on line and under control.

PAULSPEED

Hi,
I was braking hard for a left hand 90 degree turn and appling power
for the long straight. What I did was add the power to fast which caused the car to spin a 360.
Paul

PAULSPEED

Hi,
The track was Buttonwillow in California. The temperture was about
85 f. I had the tires nice and hot (guess about 125 f). I was braking into the turns from the long
straights and the traction control was kicking in. I was running Yokahamas on 305's
and had the air pressure at 35/42. The car was sliding all over the track. You
guys are right that I was not smooth in adding the power. I also braked a little to late
so I got myself out in the marbles. I was really having fun tossing my car around the track.
I run blue Pagrid pads which helps with late braking. I was also new to this track.
Paul

TheOldMan

The PASM sport mode can also be very useful in very twisty roads. There is a local road (St. George on Rigaud mountain) that is very twisty with many back to back 90degree turns. I practice going fast on this road as it makes for a technical drive. Without PASM sport mode on, the car leans too much. The road is not smooth by any measure, but with PASM on, the car is much more stable with none of the lean that I experience.

As a note, I always leave PSM engaged. It has kicked in only once in two years, but it probably saved my car the time that it did. It was my own fault, air temperature was 5C, I went around a corner quickly and floored it in second before the car was completely straight. The PSM kicked in dramatically and straightened out the car. It was almost magical the way it did that. From that point forward I learned , be careful when the tires are cold and keep PSM engaged.

8haggis

I have recently "graduated" from a '86 Carrera to my '06 Carrera S. I have had several DE events here in Michigan in the old car. The car would really communicate with you to tell you where the limits are, but boy would it bitch slap you if you didn't listen. The 997 has much higher handling limits than the old car and it is very nice to know you have that PSM to help you out if you forget to listen to the car when it finally does get to its limits. I agree with some of the other posts that it is very rare to break this thing loose if you know what you are doing, but sometimes, once in a blue moon, we don't. My moment of stupidity was in the rain and PSM stopped me from an off-track excursion.
The PASM is also a wonderful little bit of kit. I always have it engaged in sport setting in the dry as I feel it gives me a bit more tossability to the car. Mid corner lifts to get the car to pivot just a bit more and then dive into full throttle for the turn exits just before the apex feel more sure and steady.
Then, for the ride home on SE Michigan's splendid roads, you can turn it off and avoid back trouble.
Love my 997!

1100S

Just to (hopefully) add a bit to the track impressions. I took my '05 997 S with sport chrono to a DE at our local track about a month ago. I've got lots of experience at various tracks so was put in the advanced group. All of my background on track however is in open wheel race cars. I'd read lots of stuff here (thanks) and in various publications about PASM, PSM on/off etc. so was interested to see how it worked for me. The track is 1.5 miles in length but has several 2nd gear corners that are quite tight. The normal approach is to trailbrake in and use the power to "steer" around the corner. First session I just left everything as on the street. When I tried to get the back end out the PSM abruptly cut in and straightened the car out. It definetly worked but the combination of individual wheels braking and engine backing off was very unsettling and kind of "herky jerky". Great for the street but not so good on a race track. Next session I hit the sport button and found that the ride was too stiff causing it to bounce in the heavy braking areas, which resulted in the ABS coming on prematurely. Switched the shocks back to normal and the ride was much more controllable and the faster throttle response was much better especially for heel/toe braking. Throttle response was much closer to normal race car set up. The last sessions I switched off the PSM despite many (even at this event), telling me I would spin! The car was literally transformed. Car would enter corners much better and turn under throttle conditions the way a track car should. At that point it is interesting that PSM is not Traction Control. The inside wheel will spin easily but due to it's size hooks up nice and smoothly. BY the way, I didn't spin! I also found that you cannot left foot brake even with PSM off. If you try to brake while still on the throttle the engine cuts and takes a few seconds to "rearm" I tried this out even going down the lane after washing the car and trying to dry the brakes. I found this all very interesting. So on a very tight track I would turn the PSM off, on a big track with fast corners I would leave it on and of course on the street it could save your bacon. Hope this helps a bit.

10 GT3

Actually Walter Rohrl's only sub 8-second time in a Carrera S was with PASM in Sport Mode and PSM turned off. The big factor was getting control away from PSM to better control drift and slide in corners.

The advantage to PASM is you can change the dampening rates on the fly and increase them 20-30% in Sport mode. This means you get a better compromise of ride versus handling. On a smooth track, I am sure you will run better times with PASM in Sport. The disadvantage is that PASM only changes the dampening rates and not the springs rates or roll rates whihc would have a much bigger change on balance. PASM is also not the best handling suspension from Porsche. In Europe, they have an M030 sport suspension option that deletes PASM and instead has about 30% higher rate springs, stiffer valved non-adjustable shocks and an LSD. It is unfortunate that this option was not made available to the US market.

RonCT

What you and I read about what mode the car was in differ. I read a Porsche quote that said he had a slightly quicker time in normal mode and that the sport mode was too stiff for The Ring. I do think it all depends on the track...