STi in the snow

[nobody >]

You can actually make it four-wheel with judicious use of left-foot braking.
Because diffs are lazy (from an engineering perspective) it will put most of
the torque to the wheel that is slipping. Applying a bit of brake will force
it to balance the torque better. While, it won't work as well as fully
locking diffs, it is pretty effective at getting you unstuck.

I've been left-foot braking for years, it actually bugs one of the guys
at work when I'm driving the "land barge" up to a mountain radio site in
deep snow. Land barge = F550 Ford 4x4 crewcab with 8'bed.

Land Rover and Jaguar "do it for you" in their traction control systems,
and I'm certain that automated braking is at least part of the new
stability control systems that have come out recently.

My first experience with left-foot braking was drag racing 35 years ago.
I had an auto trans Chevelle with a fairly lumpy cam. It actually
launched better if I kept the brakes on lightly when leaving the tree.
The trick was learning to get off the brakes as quick as possible once
the tires hooked up well.

 

[Bonehenge (B A R R Y)]

You can actually make it four-wheel with judicious use of left-foot braking.
Because diffs are lazy (from an engineering perspective) it will put most of
the torque to the wheel that is slipping. Applying a bit of brake will force
it to balance the torque better. While, it won't work as well as fully
locking diffs, it is pretty effective at getting you unstuck.

FWIW, this is how many electronic "traction control" systems work.

The ABS sensors see a spinning wheel, the computer applies brake to
the spinning wheel, the diff transfers the power to the wheel with
least traction, which is now the wheel without the brake force..

 

[JD]

I've been left-foot braking for years, it actually bugs one of the guys at
work when I'm driving the "land barge" up to a mountain radio site in deep
snow. Land barge = F550 Ford 4x4 crewcab with 8'bed.

Land Rover and Jaguar "do it for you" in their traction control systems,
and I'm certain that automated braking is at least part of the new
stability control systems that have come out recently.

My first experience with left-foot braking was drag racing 35 years ago. I
had an auto trans Chevelle with a fairly lumpy cam. It actually launched
better if I kept the brakes on lightly when leaving the tree. The trick
was learning to get off the brakes as quick as possible once the tires
hooked up well.

I believe they are Torsen diffs. If so, no braking is involved. It is a
progressive clutched system that locks up the diff on detecting slip (speed
difference between the two wheels);which is similar to how the STi
electro-mechanical centre diff works. Most other Scoobies use LV Centre
Diffs that work quite differently.

 

[JD]

FWIW, this is how many electronic "traction control" systems work.

The ABS sensors see a spinning wheel, the computer applies brake to
the spinning wheel, the diff transfers the power to the wheel with
least traction, which is now the wheel without the brake force..

Makes sense

 

[Richard]

I just tried the left foot braking technique when my tires started slipping
on snow. The ABS light came on. What does that mean? I have a 99 Outback
Sport.

 

[isquat]

I just tried the left foot braking technique when my tires started slipping
on snow. The ABS light came on. What does that mean? I have a 99 Outback
Sport.

It means there is no center diff, lsd in the rear
and, consequently, you only have 1 driven wheel per axle
as opposed to 4 on the STI ;-) Your experience puts
the $14-15k of the price difference in perspective.
You get what you pay for.

 

[isquat]

I just tried the left foot braking technique when my tires started slipping
on snow. The ABS light came on. What does that mean? I have a 99 Outback
Sport.

It means you're in the market from the front, rear diff, possibly DCCD
and dedicated snow tires not necessarily in that order. The difference
between two and one driven
wheel per axle and the $14k price difference in case you
wonder. Of course STI gets better suspension and the engine
but $50 spring take offs from STi take care of the suspension
problem. I bet installing LDSs is more work though.
Probably at least 3 hours for the front according to
cobbtuning last time I checked. I think they have a bolt on
in stage 3 for the drivetrain upgrade kit.
In this context it's a bit ironic that FHI does not recommend
sti for snow (and ice) where every bit of grip counts.

 

[Richard]

I don't plan on changing anything on my car. I am just wondering if given
the setup I have, is the left foot braking technique of any value in
helping me getting unstuck in snow?

 

[isquat]

I don't plan on changing anything on my car. I am just wondering if given
the setup I have, is the left foot braking technique of any value in
helping me getting unstuck in snow?

I don't know. Probably not. In case of one driven wheel per axle the
proper winter shoes are more important. But, then,
you don't plan to change anything on your car.

 

[avatar70]

You can actually make it four-wheel with judicious use of left-foot braking.
Because diffs are lazy (from an engineering perspective) it will put most of
the torque to the wheel that is slipping. Applying a bit of brake will force
it to balance the torque better. While, it won't work as well as fully
locking diffs, it is pretty effective at getting you unstuck.- Hide quoted text -

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[JD]

It always works for me. It forces the car to drive both wheels on each axle