Re: Unexpected Vehicle Dynamics Part II

[cmice@mfg.mke.ab.com (Christopher Ice)]

>We were late for "The Nutcracker". I was zipping down a residential
>shortcut lined with parked magic wagons and 40 year old elms, going
>too fast, about 60K. As usual, the car occasionally "hunts" from side to side

Correct me if I'm wrong, but I think this is a side-effect of the Torsen
diff.  As it xfers power from the slipping wheel to the gripping one...the
gripping one tends to push you to one side.  Ie. if the left slips and the
right grips, it will try to turn the car to the left.

Anyone else have this?

>trying to find a spot in the groove that suits it. On one such oscillation,
>the rear tires climbed right out of the groove to the right, while the front
>tires stay relatively in it. In the small time I had to react, my dusty brain
>said "oh-oh, you're going too fast", and lifted the throttle (I now
>believe this was my fatal mistake). The car began a 180 degree
>rotation, vectoring off to the front left, coming to rest in a snowbank
>(miraculously missing all solid objects) facing back the way we had just
>come.

[The following is a personal opinion...]

This was probably bad.  If you lifted off the throttle completely, the drag
of the engine probably broke the wheels loose...the equiv of hitting the
brakes pretty stiffly without the benefit of ABS.

I would have lifted off *slightly* OR put the clutch in and lightly
modulated the brakes to reduce speed but not induce drift (or induce it in
controlled amounts).  ABS can help do this, but I feel soooo helpless when
I'm sliding w/only the ABS to save me.

The other option would be to try to use more throttle and steering input to
coerce it back into line, but that probably would have produced a worse
result if done improperly.

Get some good snow tires and suffer for the winter!!!  ;-)

[professional driver on closed course...do not attempt these
maneuvers...doing so will void your warranty...wear your seatbelts and
drive responsibly....remember, these are highly modified professionals
using specially trained equipment]

Chris

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