So, what I'd like to know is whether DSC with traction-control constitutes positraction in an S-Type?

I do know, that when the fluid coupled transfer case was replaced with an open design on the X-Type in '04, that traction-control was "substituted" for true AWD. It actually worked, to some extent. When a wheel lost traction the traction-control would apply the brakes and torque was routed to other, nonslipping, wheels. It "kind of worked" but was really a kludge as far as real AWD was concerned.

So, with an S-Type will traction control be applied to a spinning wheel and will torque be send to the other wheel? Or will the car just sit there and smoke one tire?
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Understeer is when you hit the wall with the front of the car
Oversteer is when you hit the wall with the rear of the car
Horsepower is how fast you hit the wall, and
Torque is how far you take the wall with you

 

As far as I know, the DSC in the S-types will apply braking to the tire with no traction then cut the power to the motor. I wish Jags had the half mode that BMWs have (applies brake, but doesn't cut engine power).

 

I thought positraction was about an LSD. Confused, now

But... what Michael said.

 

I wouldn't utter DSC and positraction in the same breath. Completely different devices with different purposes. Positraction effectively turns a differential assembly into the equivalent of a 'solid axle'. Sounds ideal except that instead of having just one wheel spinning, it's easy to get both spinning. Not much fun on snow or ice where directional control is a good idea.

DSC will partially apply the brakes on the wheel that is spinning but lets the differential do it's thing. It will then reduce engine power if the braking action is insufficient in eliminating the spinning. It hinders as much as it helps when trying to accelerate. I normally turn it off in heavy snow.

 

>DSC will partially apply the brakes on the wheel that is spinning but lets the differential do it's thing.

But will torque be vectored to the other wheel? DSC on an "AWD" X-Type will cause other wheels to begin turning when the spinning wheel is stopped. It won't simply brake the spinning wheel and cut power.
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Jaguar - it's not an automobile, it's a Motorcar

 

A differential's job is not to vector torque, it's to permit a differential in speed between two output shafts. It does this job perfectly but with the inherent flaw that the torque follows the path of least resistance whether this be a wheel slipping on ice or, like the outside wheel in a corner, simply be easier to turn.

If the DSC applies the brakes on one wheel due to excessive slippage then the 'resistance' on that wheel has increased. If the input from the engine remains constant then it could be said that an increased amount torque would then be available for the other wheel, proportional to what is no longer being wasted on the other.

The key is remembering that DSC's sole job is to prevent excessive differential in wheel speeds, not to direct torque.

 

Positraction is one of GM's brand names for a limited slip differential. They also called it Safe-T-Track, Anti-spin and several other names.

 

Thanks!