Could somebody elaborate on mechanics of how exactly those two animals co-exist together?
Or is Quaife presence completely 'transparent' for PSM so it does not even sense its involvement?

Also, who sells Quaife here?

 

LSD is a mechanical system, PSM is an electrical system.

The LSD's will allow the energy to go to wheel with the most grip, while the OEM open differential will send the energy to the wheel with the least resistance.

PSM (Porsche Stability Management) is a traction control system. As marketed by most automakers, but related to ABS, is Traction Control. Traction Control is used to prevent the drive wheels from losing grip when accelerating. Spinning tires during hard acceleration may be dramatic, but it is the slowest way to get to your desired speed. Using the car’s ABS speed sensors at the wheels, the Traction Control computer compares the drive wheel’s speed to the car’s road speed. If there is a loss of grip event during acceleration, there are a number of ways that the Traction Control slows the drive wheels so they can regain grip. The most common method is to use the braking system. When the drive wheels lose grip, the ABS computer can apply the brake to the wheel that has lost grip to slow it down so it can regain grip. Another method for slowing the slipping wheels is to reduce the amount of power applied to them. The computer will electronically modify the amount of fuel entering the engine and/or use the transmission to slow the drive wheels so they can regain grip.

I have the Quaife in my car, and I will get some traction control lights flash from time to time that make me wonder what it is doing. I have seen the light flicker when accelerating hard in a straight line on a surface that has high and low spots, but the car seems to continue without interference.

If you are going to track your car a lot, get it, your exit speed will increase quite a bit. If it is for street only, you will hardly get the chance to use it, unless you are trying to out run the cops!

 

Well, similar to PSM system in my Lexus in all ingeniously designed wisdom of it blocks my both wheels completely when I drive uphill on a snow and one wheel get on ice - it sort 'prevents' other wheel with good grip too to pull so car efficiently graciously slides downhill right into amazed unlucky driver who happened to be behind me.

Well, I do not drive on snow mountains too much in MA but sometimes I get to NH or Vermont and there it is a common thing.
I have developed reflexes to push that little button down below under the Lexus console to turn it off in such conditions so i could simply spin both wheels until it burnes throw the ice but was thinking to get something done on 997 to prevent such situation from the beginning.

I am still trying to understand what PSM will do exactly if my wheel on ice is efficiently stopped by LSD but other side with good traction still goes on. You imply it will apply brakes to slipping wheel only? not to both?

Did you try to drive you car on real snow/ice to see how it behaves with LSD and PSM on?

 

Most of the tracks are closed when the snow shows up, so my car doesn't go out below 7C. When the weather gets ugly, I drive my Touareg. Gets through the snow very well, no slipping, and the only button I press is the one under my right foot!

 

Please chime in if I'm mistaken, but a quaife unit will not solve everything in the snow. Granted, it will be better than an open diff in most snowy conditions, the unit does need some friction to function. Just as it won't help you if you lift a wheel on a track, in other zero resistance scenarios (a hill with some ice) it will function just like an open diff.

 

I would imagine that this is correct.

When I get stuck in the snow in my Touareg, I lock the diff's and it climbs out.

 

While we are on the topic, does anyone know what happens with a 997.1 C4 if you throw a Quaife in the back? (The car has an open diff OEM, right?)
I think the C4 car has three differentials: rear, center, and front. If you put a limited slip in the rear, wouldn't you also want to throw one up front?