rs10

PASM and PSM – same on 2wd as on 4wd?

Well, for the suspension I know the dampers and springs attach differently to different places, but it’s the damper behavior and the software (for the PASM suspension and PSM) I’m wondering about.

The reason is that I’m thinking of converting a 4wd 997.1 to 2wd. (And I guess this is most common for turbos, so I'm posting here, though I've also just posted a similar thread in the regular 997 forum.)

Regarding PSM, my fear is that PSM on 4wd cars is programmed to work quite differently from that on 2wd cars, and will no longer work well.

Re. PASM, I’m worried that removing the heavy 4wd hardware (and some other weight reduction steps) will make the car lighter, especially at the front – and that a suspension designed for a heavier car won’t work well on a lighter one. To the extent I would need shorter or softer springs, that's easy to arrange. The PASM adaptive dampers however ...

So what I’m hoping to learn is that, in fact, all the software is the same, and the dampers are basically the same, after taking into consideration the different positioning.

Anyone have any insight into this?

And if the software is different, anyone know if it would be possible to switch to the 2wd software/software settings without invalidating the Porsche used car warranty? (Yeah, I know the 2wd switch itself would invalidate the warranty, but that's reversible, hopefully invisibly - not sure about software changes ... )

(Actually, if there are software differences, anyone know if it would it be a matter of erasing the old settings and saving new ones, or just a matter of choosing between many settings that are already written into the car's ECU or chip or hard drive, or whatever? On my BMW, there are various options/features a mechanic with a laptop can turn on and off, including some that aren't supposed to be available with the car. Seems to me that it MIGHT be better from a warranty standpoint to change settings than to rewrite software.)

Thanks!

Boeing 717

Couldnt you get some computer guru to set your car to GT2 specs??

pete95zhn

On 996
-PSM is heavily (hardware) protected, no way to reprogram it.
-2WD and 4WD cars have type specific hardware.
-2WD PSM unit discusses only with 2WD Motronic, 4WD PSM only with 4WD Motronic. This feature is (hardware) protected in Motronic too. AFAIK no-one has even tried to go around it.
-however if you convert your 4WD car to 2WD, the PSM works perfectly OK. There are quite a few cars running like this without problems, including mine. *If there's differences I'd say that they're in TC part, not in SC.*

rs10

That's what I'm hoping. And if so, the question is whether it would kill the Porsche warranty, or it could be reversed and hidden. Though based on pete95zhn's post, if 997s work like 996s, then there are hardware differences as well ...

rs10

Interesting, so to be sure I understand correctly, by TC and SC you mean traction control and stability control? I probably don't mind if there are small TC differences. What could be the downside? Maybe the 4wd PSM system might be slower to cut power to the rear, since the center diff would normally redirect it to the front? As long as SC is there to stop the car from spinning, I don't mind if the wheels spin a bit.

When you say running without problems, I'm hoping that means you've really given the PSM some challenging tests, e.g. driving on a wet track, or something like that. Have you, or do you know of others who've done so? (Including perhaps someone who's done it with a 997?)

Finally, I'm interested in finding someone who can do the work for the 2wd conversion. Can you recommend anyone?

Thanks!!!

pete95zhn

Correct

This is what I suspect, if there's any differences.

Two winters (real ones, with lots of snow) with that conversion. 800 Nm of TQ... Plus "some" track time. At track both SC and TC work, TC is more subtle, you mostly notice it from blinking light on dashboard. SC's interference is more noticeable. But as it's slower to drive with PSM on, I disconnect it from the switch. Yet it's there to save me...

Use the search-function in 996 and 997 turbo boards.

rs10

I did that half a year ago. I came away feeling not many people had done it, so I wasn't sure it was a good idea, and I dropped the idea for a while. I don't remember seeing any posts saying who does such work. There may have been some mention of someone - vivid racing perhaps - but I seem to remember it wasn't clear whether they actually worked on the 4wd system of the car in question, or just helped with the engine. I can look again ...

Anyway, thanks much for the helpful (and encouraging) insight!!!