Launching for drags w Steptronic

[Kirby]

...
The brakes & engine should act independantly, wouldn't the car should just think its pulling a really heavy load or up a very steep hill with a sumo wrestler behind the wheel.

How does this damage the transmission?

That's my opinion as well. The stresses created in the transmission when doing this are likely less than flooring it from a standing start without the brake. It's very likely that a manual trans. launch by popping the clutch is harder on the rear and driveshaft than the automatic "soft" launch. The big concern is temperature. Doing this to much/too long WILL cause the torque converter and fluid to heat up - and of course that's bad.

Regardless, in my case, doing this maybe a dozen times a year at some autoX events is a known risk I'm willing to take.

 

[Blue]

"Turn off braking control (hold DSC button for 5 seconds until BRAKE light comes on)" -Kirby

What exactly does this do? I am new to BMW & don't yet fully understand the DSC feature.

Thanks,
Blue

 

[Kirby]

Here are excerpts from the manual. It is vague as to the exact function of some of the items, and when I read it I think some of it may contain typos - note the unexplained terms, ie CBC/DBC. I'm pretty sure others here may know or speculate a little more detail.

What I do know is that:
1. The computer will modulate the throttle position (torque control) and apply the brakes to the wheel(s) when it detects wheel slip.
2. Turning off by holding down the button for at least 3 secs. disables throttle and brake intervention.
3. Anti Lock braking is not directly related to the DSC and will continue to function regardless of DSC status.


From the Manual:
"DSC incorporates the Dynamic Traction Control (DTC) and Cornering Brake Control (CBC) functions.

Indicator lamps:
The indicator lamp in the instrument cluster goes out shortly after the ignition has been switched on; refer to page 19.

The indicator lamp flashes:
DSC is actively controlling drive torque and braking intervention

The indicator lamp stays lit:
DSC has been switched off with the button; DTC and DBC are operational. DTC control intervention is not indicated.

The indicator lamp and the brake warning lamp continuously light up in yellow:
The DSC, DTC and DBC have been switched off manually or there is a system malfunction.

Deactivating the DSC/activating the DTC
Press the DSC button briefly; the indicator lamp comes on and stays on. DSC is deactivated; DTC is operational.

Deactivating the DSC and the DTC:
Press the DSC button down for at least 3 seconds; the indicator lamp and the yellow brake warning lamp will remain on continuously. The systems for enhancing stability and traction are deactivated, and there is no active braking intervention or torque control.To maintain vehicle stability, always drive with the DSC activated whenever possible.

 

[Blue]

Thanks, good info. The owner's manuals are always pretty sketchy. I used to wonder who wrote them, then one day in college I found out that one of my fraternity brothers wrote manuals for Toyota in between six-packs!