Why does my BRZ have LESS traction with traction control on???
 

We had a surprise 6 inches of snow yesterday in south jersey.(the weather guys got it wrong!)


Anyway, our driveway has a slight incline. With traction/stability on, my BRZ got stuck at the end of the driveway and just spun it's wheels. With the systems OFF, it went up the driveway with no problem!


What gives? Shouldn't traction control help traction and not make it worse?? (before you ask, all season tires)

you would think but my experience with TC (in all cars that have had it) is just to turn it off if you need to get out of snow.

IIRC, TC cuts power to the wheel that's spinning....so it stops trying to get you up the hill. Makes sense to me a system designed to recover from traction loss has issues when it's slick out and you want to push through it.

What others have said. Also, this car has LSD which probably makes it easier to get up a small inclined in snow conditions like yours. My Cobalt SS had a similar issue. Had to disable the TC to get up my parent's driveway.

One word: momentum.

Your T/C system tries to keep traction at the cost of momentum, your right foot don't care if it breaks traction as long as the car keeps moving. In very slippery conditions all you need to get anywhere is to keep the momentum, regardless of wheel speed.

all makes sense....more snow on its way tomorrow!

In loose snow you can get more grip with a bit more wheelspin than traction control allows. With some designs of snow tires this effect is even more noticeable.

Momentum is not relevant, this applies from a standing start.

Others have already said it, but I this might make it easier to understand for some...

Disregard the words.

Traction Control and Vehicle Stability Control is what it's called in our cars, and gets named something differently for different cars.

Think of it conceptually instead.

TC is a system that prevents power from being applied to whichever wheel that loses traction in an effort to prevent loss of control. When attempting to drive through that snow up an incline, you're wheels are going to be losing traction. TC thinks you're vehicle is losing control, and so it cuts the power to the wheels. In this situation though, cutting the power isn't going to help you regain traction. In this situation, you need more power so that the wheels spin enough that they gain traction through the snow.

VSC isn't going to help you either. VSC keeps the car going in the direction you are steering. Basically, VSC only engages when you experience understeer or oversteer that doesn't line up with the direction you are steering the car in. VSC will help you while driving in snowy conditions by helping to prevent you from spinning out, but it's not going to help you while you're trying to get in/out of your driveway.

[ame="http://www.youtube.com/watch?v=MMrBDdLGB20"]How Vehicle Stability Control (VSC) works - YouTube[/ame]

TC actually applies a brake to the spinning wheel before it controls engine torque. You can hear the brake going on and off.

Only if applying the brake is insufficient does the TC begin reducing torque. Nowadays this is done using an override on the electronic throttle.

I think VSC also backs off the TC a little and allows some additional wheelspin, otherwise you wouldn't get the rear end out before the VSC reigns things in and you can. It's intended for the track for those not confident enough to switch the traction and stability aids completely off but it also works for slippery stuff.

The stages for winter traction are TC on, then if insufficient forward motion try VSC on. Then if you are still stuck try TC completely off. Works best with snow tires and probably doesn't work at all with summer tires.

This goes back to the thread where people said I was crazy for preferring to switch the nannies off at times.

Honestly, this car would need twice the power for me to consider leaving them on.

You wouldn't happen to know what all you lose when you pull the ABS fuse would you?

I do not know.

The pedal dance is an option, albeit one which leaves ABS functional.

Puts the car in limp mode I'm fairly certain.

I've read of (and encouraged) a number of people doing just that for track days and otherwise. Everything seems to work just fine, apart from deleting ABS, EBD, traction control and stability control. The computer has been removed from the equation.

What concerns me is the loss of the front/rear brake proportioning. However, so far no one has reported any particular problems related to that.