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I can give you a very basic understanding, I am sure someone else will be able to answer better.
TCS = traction control system. when wheel slip is detected, it cuts off power to individual wheels to keep/straighten out the car until traction is back
ESC = ?? electronic stability control? I imagine this is the same thing as Stabiltrak.
StabiliTrak = when loss of steering control is detected, the car automatically applies brakes to help steer the car whereever you are trying to point it
LSD = limited slip differential. ever heard of one tire fire? this is in the center differential of your rear axle that helps distribute power/torque evenly, iirc.
thanks for the info. I've also heard that TCS is more of an engine fuel cut (which takes power away from both rear wheels)
Where I'm getting confused is how these systems work together. For example, if you gun it while turning right, does the following happen?
- TCS cuts power to rear wheels
- StabiliTrak brakes both right wheels
- LSD sends more torque to left rear wheel
It seems like the TCS and LSD would be working against eachother.
TCS is traction control only. I seem to remember reading that it first applies a rear brake to the wheel that is spinning (via the ABS it supposedly knows what's going on), and that if that's not enough it will cut engine power.
ESC and GM's Stabilitrak are for directional stability control primarily while cornering. These systems are also piggybacked on the ABS and can selectively activate only one brake to hold either heavy understeer or oversteer to within somebody's definition of acceptable limits. There actually is a spec value defined in terms of how fast the car is changing its heading (something to do with yaw rate) at which these systems are supposed to start intervening.
In the example of gunning it while turning right, what actually takes place probably depends on what is sensed to be "out of bounds behavior" first. Without LSD (or with a worn-out LSD) I suspect that RR wheelspin would be the first indication, and that would kick the TCS in on your RR. I'm guessing that ESC would apply the LF brake if TCS wasn't enough to bring the presumed amount of oversteer back under control, as that's one of the ESC options.
With a LSD in good condition, you'd be more apt to spin both rear tires instead of just one a lot more than the other. Expect this to get the tail loose enough to bring the ESC into action, which would probably activate the LF brake as a start. I don't know if ESC will cut power or not - I have an '08 which (thankfully) does not have ESC. (I'd turn it off if it did just like I do with the TCS that it does have, anyway.)
LSD is the limited slip differential, which allows one wheel to run a little faster than the other to permit easy turning where the rear wheel speed have to be different. It'll try to lock the two wheels into running at the same rpms, usually by some friction mechanism or other, which can be overcome as long as there is enough grip under both rear tires. In a straight line, it's usually enough to keep only one wheel from spinning.
'08 GT/5MT (mine)
'10 Subaru Legacy 2.5GT/6MT (hers)
'95 626/V6/5MT (autoX, winter, spare)
'01 Maxima 20AE/5MT (other spare)
Last edited by Norm Peterson; 04-16-2012 at 07:20 AM.
Reason: spelling, context
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