pantdino

So PSM was stock on all 996's or just the C4?

Of all the ads I've looked at only one mentioned it, so I don't know what to make of that.

pantdino

Some of the adds state "traction control."
Was that a separate (and I presume standard) function, or is that the unknowing person's way of saying PSM?

Dennis C

The traction control system is part of the PSM system. There was LSD (Limited Slip Differential) available on the 1999 cars, but not the later cars. PSM wasn't standard on all 996 cars, but it was on all AWD cars.

ALE

Dennis C, to be accurate, the 40th anniversary cars came with LSD.

Ahmet

Traction control was available in 1999 in the C2. All AWD 996 models (C4, C4S, turbo) had PSM standard, traction control was no longer available after 1999. PSM was never standard on the base Carrera models. PSM does include a "traction control" function, but it is different in design than the system available in the 40th and the available (optional) traction control system in the 1999 Carreras (as those incorporated a low lock up ratio limited slip diff). Namely, PSM includes yaw/steering angle and suspension compression sensors, and is able to brake all wheels independently, or relieve braking pressure. Also, if memory serves me correctly, it's able to open the throttle a couple of degrees upon lift off throttle steer.

PSM on 996s is primitive by modern standards and it does very annoyingly intervene (even when switched off) if the brakes are applied. At least it allows off brake sideways shenanigans and throttle oversteer.

Dennis C

Good catch.

Spinout

I've been reading the 996 Companion book recently and it states that PSM allows a 7 degree slip angle before coming to the rescue

CarlosCA

Great points. C4S is a tremendous athlete no question. Having one of these with X51 would take it even further.

kromdom

post #10: https://rennlist.com/forums/996-foru...questions.html

https://rennlist.com/forums/996-foru...an-option.html

good read about PSM: http://www.deter.com/porsche/PSM.html

03996

Which I have NEVER understood!.......great looking car, great performer. So what it was the first water bird........all that have come since are the same. LOADS of car for the money.....well undervalued......ok, maybe I'm biased but from an unbiased viewpoint.......a GREAT car!

Luckyr

I am so happy to dig up your comment. I put my summer Sumitomos back on a couple of weeks ago (for the winters-- Michelin Pilot Alpins) and started having PSM triggering on the fronts in hard corners.

As it turns out, the rears are brand new but the fronts are about one dry season from being at the indicators.

At first I thought the alignment (which I had never had adjusted) was the isssue and sure enough they were a bit out of alignment but that didn't solve the problem 100%. Then I took the pressure down a bit from 36 to 32. Also an incremental improvement, but not a 100% fix.

Then I read your post and everything makes sense. I'll go ahead and replace the front tires if it persists while the weather warms up.

Question, though. Why now? No issues with slippage triggering PSM ever before on the same tires with essentially the same treadwear.