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Originally Posted by Pex5
Example: your heading down a secondary road at 70 km/h on packed snow in your E70 and you need to make an abrupt turn onto the next side street. You brake and then turn, but you're going just a bit too fast and the front end (only) looses traction and the arc of your turn increases enough to put your vehicle onto the other side of the road facing oncoming cars. At no point in my example has the accelerator been used. Therefore, the X-drive is not being used either. If you were in a 530i doing this, the DSC activates and brakes the inside rear wheel and brings your car back into the correct lane. With an E53 X5 you slide into the next lane unless you exaggerate your turn by cranking the steering wheel into the turn which "wakes up" the intentionally dormant DSC. Then the car somewhat overcorrects due to your exaggerated steering input. I'm guessing that the DPC on the X6 does much of the the job done by the aggressive DSC on rear drive BMWs info far as correcting slide in a corners in concerned?
Can anyone defend BMWs decision to calibrate the DSC this way on X cars?
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I think it comes down to the fact that fwd/rwd/awd vehicles have different cornering dynamics, especially with limited traction. Your example assumes that the cars are all driven the same, and that is not what should happen. It is an example of driver error. The awd benefit is only there if your foot is in it. In your example, the driver went too fast for the conditions, and then drove through the corner without throttle. Two errors that compound. If he went slower into the corner in your example, and then accelerated to let the awd system do what it is designed to do, this wouldn't be an issue.
I think that if you want the awd system to work as designed, you need to allow the nanny devices enough tolerance to let the drive systems work, ie not correct for a situation if in fact it is just a case of the drive system doing what it is supposed to do.
There was a thread awhile ago where a member posted that his new X5 didn't seem surefooted on snow, and he wasn't confident in the cornering of the vehicle. I suggested that he keep his foot in it (within reason) and let the system work. His response confirmed that the approach worked. I think the DSC is just doing the same thing, letting the awd work. Since BMW isn't about to add throttle automatically in those situations, that action will remain a driver responsibility, and rightly so.
That isn't intended so much as a defence, as much as a comment on why the different programming may exist.
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2007 X3 3.0si, 6 MT, Premium, White
Retired:
2008 535i, 6 MT, M Sport, Premium, Space Grey
2003 X5 3.0 Steptronic, Premium, Titanium Silver
2002 325xi 5 MT, Steel Grey
2004 Z4 3.0 Premium, Sport, SMG, Maldives Blue
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