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Can anyone point me to a technical description of how the AWD system on a C4S works? The manual does not have much technical detail.
I am interested in finding out under what condition the system decides to transfer power to tthe front wheels.
Power distribution ranges from 95% rear 5% front to 60% rear 40% front. How and when is power shifted up front, is it only when the PSM is activated and the dashboard indicator lights up? Or under other conditions?
Can power go to one wheel only like on a Quattro?
Thanks
Alain
Alain,
When I get a chance, I'll scan a few pages on AWD out of the 911 books I have. In the meantime, check out these links to Porsche's website:
http://content3.us.porsche.com/prod/...&sc=turbos.nsf
http://content3.us.porsche.com/prod/...&sc=turbos.nsf
Here's the link specifically for the C4S:
C4S AWD
. Same as the turbo. The Porsche AWD system with snow tires works well in snow. Some say better than SUV's. If you track the car, the AWD will help rotate the car. As you apply gas while going for the apex, there will be a rotational difference between front and rear axles. This will engage more of the front wheels, pulling you around the apex. There is actually a split second delay and you think you'll plow out, then feel the front end turn in as the front wheels pull the nose into the turn. Makes the C4S "ride on rails". At least, that's what I lke to think.
It works independent of PSM, and there are no lights or anything to indicate that more power is being shifted to the front wheels. It will, however, work with PSM when PSM is activated. As PSM pulses the brakes to the wheels that need to slow down, power is tranferred to the non-braked wheels simply because the rotational difference again will activate the AWD power transfer system.
I agree with Palting. I've had a 01 C4 and now a C4S (I don't believe the technology has been updated from 01 - 04) and I love the way the car handles in the rain and snow. Assuming you put proper snow tires on the car.
The PSM makes a big difference. In a parking lot with a few inches of snow I tried to push the car with the PSM on, really hard to make the car spin. With PSM off you can do a 360, just keep that in mind.
Rob
Alain,
I looked at the books I have about 911s and none of them has a good technical description of the AWD (more or less historial facts) so they're not worth being scanned and posted.
