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Originally Posted by ArthurS
I am still wondering why the brakes and wheel locked up. I was only going about 30 mph, and slammed the brakes when I saw the tree, and it all froze. I though anti-lock pumped it for you so things like that wouldn't happen.
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The ABS on the WRX is a little notorious, at least on ice and gravel. However on tarmac, it usually works pretty well.
As they say in racing, "both feet in when you spin". You were sure to get the clutch in too right? Sometimes in an autocross, I'll get on the brakes real hard, but since I got big feet, I'll be mashing the gas too, so if the clutch is out, then I lose a ton of braking power since I'm still driving the wheels.
Most likely you were just "pushing" (aka understeering). The combination of braking and steering input was more force then the traction of the tires, and the front wheels skid. There's nothing ABS can do to help this, since ABS can only modulate the brakes, and not the steering. This happens all the time at an autocross, and it simply means you were going too fast for the radius of the turn you needed to avoid the tree. In fact the ABS might not have even come on since the tires were probably still spinning! If the tire's skidding laterally, it can still be turning and therefore the ABS systems thinks all is well.
The WRX has a ton of understeer from the factory. One reason is just for safety... since the opposite of understeer in oversteer (aka "loose"), and a car that oversteers spins-out easily. The other reason is that in general AWD cars oversteer since the drivetrain binds a bit when the inside and outside wheels spin at different speeds. Many people install a stiffer rear swaybar to help make the car more nutral. I put an adjustable Whiteline bar on mine, so I can loosen it up for autocrosses, but keep it easier to drive in the snow during the winter. A good set of properly adjusted springs/struts or coilovers will also tune out understeer.
Phew, that post got a little long!