Let's talk about quattro driving in the snow

[Sean Ford]

--- Brett Dikeman <brett at cloud9.net> wrote:
> Scott, let me know if I say anything really stupid here :-)
>
> Disclaimer- I'm not an expert(I'm not an instructor, either), you're
> responsible for your own driving, blah blah blah yadda yadda.
>
> At 5:08 PM -0800 12/3/02, Sean Ford wrote:
> >This is my first winter with quattro. Just this morning, with fresh
> >snow on the ground, the front
> >slid straight and the car continued to move in a straight line.
> >Obviously, this isn't the best
> >situation when one is expecting to successfully complete a corner!
>
> Actually, it's a lot better than the alternative(oversteer.)
> Understeer is what happens under power, and it's usually easier to
> correct in a FWD or quattro, because in both cases, your instinctive
> reaction(get off the gas to 'slow down') is a good thing.
>
>
> >I've driven both fwd and rwd cars in the snow. FWD will lose the
> >front, but a quick pull on the
> >emergency brake will swing the rear around.
>
> Pull the handbrake, and now you've lost all FOUR wheels :-)

I disagree. If a fwd car is heading straight through a corner, with the front
wheels turned, the rear wheels are just along for the ride, neither helping or
harming. With a sideways slide, in the direction of the corner, the rear wheels
are more like rudders than simply supports for the rear of the car. Think more
along the lines of rallying and less along the lines of out-of-control. It's
the out of control aspect that I'm trying to avoid.

>
> >Once I lose the front with quattro, what is the best way to rotate the car?
>
> You shouldn't be thinking of 'rotating' the car(angle doesn't get you
> around corners, GRIP does), you should be thinking about regaining
> control(ie, get the car pointed the way it's travelling) and stopping
> if necessary.

Maybe I'm missing the point, but in my mind, having 4 sliding and powered
wheels pointing at the exit of the corner is advantageous. 2 sliding powered
wheels pointing at the exit and 2 non-sliding powered wheels pointing straight
ahead sounds like a recipe for disaster. I really feel like I want to rotate
the car, lifting off the throttle might be the answer or it might just leave me
in the sliding situation until I hit something solid.

>
> Two reasons:
>
> a)if you DO hit something, you're hitting it in the worst possible
> way, with the side of the car or at some angle other than head on.
> Cars and restraint devices are designed for head-on collisions.  This
> applies even if you're going to go into traffic; if you've got
> understeer and you're heading into the oncoming lane for example, and
> you decide to rotate the car by inducting oversteer, that places
> about 4-5" of car between you and a car coming at you with a
> differential of at least 40-50 mph...versus several feet of metal,
> crumple zones, airbag, seatbelt, etc.
>
> b)if you get the wheels gripping, you've at least got a prayer of
> slowing the car, and every bit of speed you can bleed off is speed
> your body, your car, and the other object don't have to deal with
> later.  Sideways?  You're a passenger on a slip'n'slide.
>
>    When Chris Miller crashed at Watkins Glen, he did the right thing-
> he got the car going straight, and just whaled on the brakes, because
> he knew he wouldn't make it.  The result was that right until he hit
> the foam wall, his nice big porsche calipers were slowing the car and
> his nice sticky tires were working 100%.  Between that and the foam,
> he walked away without a scratch and the engine was fine save torn
> mounts and cracked tbelt cover(body was a complete loss from the
> mirrors forward, pretty much.)

Ok, these are obviously worse case scenarios, and very valid in a real world
sense. Let's get all laboratory sterile here, though, and imagine an empty
snow-covered road. Part of this exercise is for fun... scrubbing speed off is
the right thing to do in most situations, but what if I want to slide through
that corner 'cause it's cool? ;-D

>
>
> >  I recall some advice warning against lifting off the throttle
> >because the engine braking on the rear wheels could cause
> >an unwanted spin.
>
> The warning is for lifting mid-turn, near the limit of traction or if
> you're in a slide. It causes a weight shift to the front of the car
> OFF the back wheels, which will cause oversteer.

So, if I'm in a slippery corner and lift, the engine braking will affect all 4
wheels, the weight transfer goes forward and to the outside (to the right in a
left hand turn, and vice versa), what would bring the rear around? To bring the
rear around, I would think there would have to be a weight in the trunk. Are
you saying that the increased weight of the front, has the effect of increasing
traction? That makes some sense to my garbled brain.

>
>
> >  Though, if I don't lift off the throttle, the front will simply continue
> to
> >push.
>
> The correct behavior, for when you've got understeer, is your natural
> reaction- to let off the gas pedal.  It transfers weight forward and
> gives you more grip up front.

Ah! That is what you're saying. More weight, better traction.

>
> >Interesting from a dynamic, after-the-event, point of view. Frightening from
> a
> >happening-right-friggin'-now point of view.
>
> Come to a NEQ winter driver school.  Bring the missus, too.  You'll
> learn a lot, and have a blast.  Heck, look what I learned just
> picking cones :-)

Yes, I do like that idea. Good suggestion!

=====
Sean Ford
1999 A6q tiptronic | 1992 100CS 5-spd
http://community.webshots.com/user/seanmford

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