505RA

iTrader: (1)

i was just wondering if anybody knows exacly what percentages each setting actually is, tarmac, snow, gravel, for example is tarmac 60/40(f/r)?

madcows

The center diff is always 50:50 which can go from fully open to fully locked, and anywhere in-between. There is a computer that determines how much lock it should apply to the clutch plates inside the diff based on things like steering angle, e-brake usage, acceleration, and presumably wheel slip. Each one of the 3 settings uses different "maps" to determine how much lock to apply based on those inputs.

I mentioned this before, but I'll do it again. Lets say for example that the front wheels of your car are on ice, and have practically no traction - while your real wheels are on tarmac with plenty of traction. If the center diff remains fully open, it's going to send power to the easiest route - the front wheels. Because of this, that car will not go anywhere because the back wheels with plenty of grip will get none of the power, while the front wheels with no grip will be spinning. However, if the center differential goes to full lock, it will cause the front and rear wheels to spin at an even rate. Since the front wheels wouldn't have any grip anyways, it's not really using much torque on that end - however, since the rear wheels have traction, they'll essentially be using all the torque themselves, making it almost like having 100:0 torque split, and vice versa. This is perfect when the car might have traction on one side, and not the other. However, if both ends have similar grip, then the system can't give you the dynamics that an active torque redistribution system (like the STI has) can. Instead, it will be more dependent on your suspension setup. Every evo that had an active center diff has used this method, and it seems to have worked very good for them.

I think one of the coolest aspects of the system is that when you pull the E-brake up, it will make the center diff go to fully open, so you can lock up the rear wheels just like rally cars do.

Piper747

iTrader: (2)

Sweet! Thats good to know.