power distribution to rear wheels

[doughep]

This is just a curiosity question.

Last week I had an unexpected - and unwanted - opportunity to drive in snow (I know, I know, put her away for the winter - but I just can't seem to do it!).

Based on the way the vehicle responded, it seemed to be pushing predominantly from the passenger side rear. After I noticed this, I experimented in some various (safe) snow covered locations, and found the behavior to be consistent on flat ground, hills, straights, corners, etc. The tread depth and wear on my tires is uniform on all four tires.

Is this a false read on my part, or does the vehicle favor one side over the other when distributing torque? I know that was pretty common 30 years ago, but I didn't think it was a common practice anymore.

BTW - my Boxster is a base model 98, if that makes a difference.

Again, just curious.

Thanks.

- Pete

[KevinC]

The Boxster has an "open differential". Equal torque is delivered to both wheels and that's the problem. The torque delivered to a wheel with good traction is limited by the amount of torque which can be delivered to a wheel which is slipping.

Open differentials are quite standard on modern road cars. Some performance cars come with Limited Slip Differentials. These ensure that the wheel with more traction will get more torque than the wheel which is slipping. LSD's are not available on Boxsters. However, the Traction Control option provides a similar function using electronics and the brakes. TC monitors the ABS wheel speed sensors and when it sees that one wheel is slipping, it applies the brakes on that wheel, thus increasing the torque the engine can deliver to both drive shafts. It sounds like your '98 was not equipped with Traction Control. (On newer Porsches, traction control is a subset of the functionality provided by the PSM system)

[BobMarley]

I have a 2002 and it has the same issues...