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Originally Posted by silvrevo
Im glad somone asked this question. So dtc will act like a car with lsd. So why is it that the 335i cant lay down 2 tire marks, only one? I think that is with dtc off. With it left on will it do this?
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Please re-read Jeftrz's and BK's posts. They really did not say that they will act the same.
An lsd-equipped car will deliver torque to both wheels at the same time. Torsen and clutch pack type lsd's will always spin both wheels because the differential speed allowed between the 2 wheels is not infinite (unlike an open differential). It is usually limited to a max percentage difference. (Although in a Torsen differential the wheels see an open diff but the engine sees a a locked rear end because of very high ramp angles in its worm and roller gear set up).
Viscous coupled lsd's require some single wheel spinning to occur before the diff starts to lock up and spin both wheels.
BMW's DTC is still an open differential. The wheel with the least traction will get most of the power and will spin. DTC will then quickly intervene with that wheel's brake and transfer the torque to the other side. The wheel must loose traction first before DTC will intervene. This transfer of torque back and forth makes a 2-wheel burnout unlikely. One complaint about BMW's system is that when applying full power out of a tight corner the 335i does not put its power down smoothly and quickly.
This is why BK said:
"Based on my limited understanding of how this stuff works, an LSD is extremely beneficial when exiting corners while stomping on the gas. DTC is extremely beneficial when losing traction due to road conditions. But neither does the other's job nearly as well."