Quote:
Originally Posted by sy2767
I have noticed that the consensus seems to be that BMW's system is under par and almost frowned upon compared to other manufactures AWD systems, what makes it an inferior design?
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As mentioned by AJ, mechanically locking center and rear diffs. The BMW system is quite simple, but it's actually quite effective. The center diff is variable in torque split front rear, driven by the DSC and other software. The rear diff is an open diff (as is the front) and uses Automated Differential Braking (ADB) to lock/slow spinning wheels, which transfers torque to the opposite side (which presumably has better traction since it's not spinning.)
However, other systems which use mechanical means to lock the left/right (and even front/rear axles) to a greater or lesser extent have advantages in some situations. For instance, unless you turn on DTC, a BMW can get bogged down due to 1) traction control dialing down power/throttle, and 2) stopping the spinning wheel may not actually cause the car to move if the other wheel also has little/no traction.
In reality, none of this matters a whole lot, as most people never approach the limits of available traction, and we're only talking about the last 5% or so of performance. Frankly, if you're at that limit, you should be home and the BMW should be in the garage.