Quote:
Originally Posted by The HACK
Based on this description, and the rest of the thread...
I'm going to say this is exactly what I suspect. The programming for DTC is left in the DSC module because BMW didn't want to customize a module just for our cars.
The fact that you can spin the tires in a straight line, where both tires are losing traction, on dry pavement with this setting enabled, and still engage DSC in a turn, means you're defeating the purpose of the mechanical LSD. The programming is left there for cars with open diffs as to interfere by braking individual wheels in the rear (by the way, said feature was available as early as 2003 when the Z4 was first introduced), but when BOTH wheels are spinning the rear brakes won't kick in because, to the system, traction levels are equal for both sides.
M-Track mode on the E46 actually is a different threshold programmed in to DSC, where on a straight-line it'll give you some leeway to spin the tires, but will eventually reign you in because a moderate amount of tire spin is good for launch (put heat into the rear tires). It also dials back DSC in the corners allow for a greater degree of slip angle before intervening.
If what y'all are saying is true, that DSC still intervenes while turning, then you're in essence using the rear brakes to simulate what a LSD would do, when the car already has a mechanical LSD to start with...And a very fancy one at that.
The quickest way to test it, is to drive around spiritedly in an empty parking lot with DSC off, then drive with the "DTC" mode on, then measure the rear rotor temp to see if it's activating the rear brakes more. If it is, then turning on this "mode" is a big mistake.
I don't have a beef in this, by the way. Now, if you can find a way to program it to default to DSC OFF when starting the car, I'll be all ears.  |
Clever idea to test, but brakes might cool off to fast.
Why it is a mistake??