Recently, my PSM has been engaging prematurely -- meaning, it engages during a rapid turn, even though I am not close to loosing traction. The dealer told me that my PSM system is working perfectly and the problem is "mechanical." They opined that the problem may have to do with my tires or brakes. I am using Brembo 14in brakes and MPSC tires (315/235). I can't be certain, but it may have started after I switched from 225s to 235s. Brembo is confident that the problem is unrelated to the brakes.

I also occassionally trip the PSM when I do a WOT sprint in fourth or fifth gear (this doesn't happen in lower gears, under less load).

Any thoughts would be appreciated.

Craig

 

a long time ago, it was said the slip angle needs to be reset (w/ Porsche system tester) when you widen the stance - front or rear.

 

Ben, can this be done??? I would be shocked (due to liability) but sure hope it can be.

 

i had it done on my c2

 

I dunno if this helps or not but have somone check your cardon shaft... I bent the splines and it started doing that. Replaced the cardon shaft and it stopped...

 

Ben,

Did the dealer reset your "slip angle"? What is involved in this? Can a tuner with a PST II do it?

Sharky,

Forgive my ignorance, but what is a "cardon shaft"? Did the dealer replace it? Warranty? How much?

Thanks for the input.

Craig

 

Are your rolling diameters front to back within a couple of percent?

Shot in the dark, but an easy fix if that's the problem.

 

I have no idea. Does anyone know how to calculate this? I have 235 MPSCs on the fronts (18x8.5) and 315 MPSCs in the rear (18x11.5).

Thanks,

Craig

 

I just got off the phone with Tire Rack:

MPSC 235/40/18 does 819 revolutions per mile.

MPSC 315/30/18 does 815 revolutions per mile.

That variation is well within acceptable limits and does not appear to be the problem.

Craig

 

Beat me to it. The quest continues.

 

yep, it was a dealer. i'm pretty sure they just plug it into the PST to reset it. there is a thing for it in the menu.

 

I've had two instances where my PSM would come on prematurely. First, there's a section on a canyon road near my home that has an off camber turn over a crest kinda thing. It almost always goes off and scares the **** outta me every time.

Second, I just put new S-02A rear tires on over the weekend. I have P Zero fronts that are about 60% gone. While braking on a turning off ramp, PSM came on prematurely also. It hasn't happened since but I've just been commuting without driving in anger.

Its pretty sensitive.