[FlashEngineer]

I'm wondering does the VDC control the brakes in snow by slowing down a spinning wheel just like the BMW or Audi so it effectively transfer torque through the LSD's on front/rear axle?

Just reading on Helical and Torsen diff's, they don't really work when 1 wheel has near 0 torque (off ground,ice) so unless the VDC applies braking on the spinning wheel, the STI will effectively have open diff's on front/rear?

[Turninconcepts.com]

Yes it does. It can apply the brakes throughout the four wheels independantly.

[FlashEngineer]

Originally Posted by Turninconcepts.com

Yes it does. It can apply the brakes throughout the four wheels independantly.

So then it would be quite good in the snow... now my question is, how did the previous STI get through in the snow if they did not have VDC to control the braking?

[helldorado]

Traction control.

Basic traction control systems detect a difference in wheel speed between the left, right and front and rear wheels and applies the brakes to those spinning the fastest to attempt to slow them down and allow them to gain traction. The system assumes that if all 4 wheels are spinning the same speed, you must have traction and be moving.

VDC is nothing more than an evolution of those systems. VDC is a system that reads all inputs from steering angle, to the g-meter, individual wheel speeds, etc.. to determine from what direction your car is facing and what direction it wants to go and how to best get it to where you want it to go through a combination of brake and throttle adjustment.

And back in the days before that, people had to use their brain and let off the gas, then try to move slowly to keep traction and not just floor it.

[Turninconcepts.com]

Originally Posted by FlashEngineer

So then it would be quite good in the snow... now my question is, how did the previous STI get through in the snow if they did not have VDC to control the braking?

If you read the manual, I believe it actually says to disable the system in the snow. I always do as I think the system makes the car less controllable in the snow.

[1loudsti]

in the older ones the snow is more fun than summer in a stock car!

*end stupid point* lol

[Turninconcepts.com]

The old ones should be a bit different. For example, my wife's outback in the snow if unstoppable, and drives like normal over everything. The STi, in order to get any kind of fun or reasonable control like the outback has to be throttle steered more.

-Clint

[Digitalfiend]

^
I noticed the same thing with my '05, it was very tail happy in the snow but very controllable...it just felt out of control in deep snow lol. It was virtually unstoppable though.

VDC and traction control are two different things on the '08+. The traction control can cut engine power to reduce slippage under acceleration, which is perfect for traction-limited situations that can't easily be handled by manual throttle. Think of ice. A computer that can sense wheel slippage and know exact how much power should be reduced is probably faster and more precise to react than we ever could.

Still, with the way the turbo works (easily controlled via the throttle) and SI drive (I-mode in low traction situations) and traction control/VDC, I honestly think the '08 should be better in the snow and on ice than previous models. Obviously tires are still the key to great traction.

[nytejade]

So what's the consensus here? Disable VDC entirely in the snow?

[CFar]

Originally Posted by FlashEngineer

how did the previous STI get through in the snow if they did not have VDC to control the braking?

Sideways

[FlashEngineer]

I'm not really worried as much as when I had my WRX in deep snow, just want to know how would the differentials handle low traction. I just kicked myself for getting stuck last winter in my WRX, mostly at fault was the weak center diff 4kg/100rpm

[USNSTI]

You guys are making it sound like older gen subies couldn't drive in the snow because they didn't have VDC. Trust me they handle the snow very well. I'm sure VDC helps though, but lack of traction in the snow has NEVER been a problem faced by any Subaru owner I ever met.

[FlashEngineer]

Originally Posted by USNSTI

You guys are making it sound like older gen subies couldn't drive in the snow because they didn't have VDC. Trust me they handle the snow very well. I'm sure VDC helps though, but lack of traction in the snow has NEVER been a problem faced by any Subaru owner I ever met.

Ahem... like i said my 06 wrx got me stuck about 5-6 times last winter.. and it wasn't like crazy places.. I can describe a few incidents...

About 8" of snow or so, backing out of a driveway that is sloped DOWN, once I got to the bottom I got stuck, I couldn't move back more or up...

Got stuck in my own driveway... 8" again.. I have like 3degree slope only...

[Turninconcepts.com]

What kind of tires did you have?

[Digitalfiend]

Originally Posted by FlashEngineer

Ahem... like i said my 06 wrx got me stuck about 5-6 times last winter.. and it wasn't like crazy places.. I can describe a few incidents...

About 8" of snow or so, backing out of a driveway that is sloped DOWN, once I got to the bottom I got stuck, I couldn't move back more or up...

Got stuck in my own driveway... 8" again.. I have like 3degree slope only...

That won't happen in an '04+ STI...you have to try really hard to get stuck. I once pulled off into a foot and a bit of snow because I had to piss real bad on a 4 hour drive and was in the middle of nowhere. The snow was coming down really hard, so I quickly spelled my name and tore out of that snow like I was in a WRC car. Seriously, with good snows like Nokian RSI or Michelin X-Ice or Dunlop Winter Sports, you'll have no problems in a STI unless you are really trying to get stuck.