Dumb question about launch control / 2013 M3

[NashvegasR]

Another user's post about launch control prompts my question here:

When I engage launch control (which I've only done 3 times on 2013 M3 e92), there is a noticeable and sort of brutal THUMP upon releasing the shift lever. Almost as if something in the rear of the car is banging upon GO. Sort of violent.

Anyone else have this? Or is launch control just like this ?

BTW reason I tried it 3x was this brutal thump. It does it every time. Watched all the requisite launch control videos online and I don't hear it or see it, and no one has commented on it I can find.

(go ahead, make fun of me)

[BanjoPaterson]

Originally Posted by NashvegasR

Another user's post about launch control prompts my question here:

When I engage launch control (which I've only done 3 times on 2013 M3 e92), there is a noticeable and sort of brutal THUMP upon releasing the shift lever. Almost as if something in the rear of the car is banging upon GO. Sort of violent.

Anyone else have this? Or is launch control just like this ?

BTW reason I tried it 3x was this brutal thump. It does it every time. Watched all the requisite launch control videos online and I don't hear it or see it, and no one has commented on it I can find.

(go ahead, make fun of me)

I've never used launch control, but from what I understand of the transmission and drivetrain is that the "thump" is probably either, or a combination of, the DCT engaging and/or the U joint in the drive shaft suddenly have to take on 3000 rpm. My guess - the drive shaft.

One thing I do know is that sound is deceptive in a car. The U joint in the drive dhaft is (from what I know) slightly behind the driver, so the sound will sound like it's "coming from the rear".

I found the damn thing thumped nearly every time I slowed down until my DCT relearnt whatever parameters its learns after being upgraded.

[Umi|all|day]

Launch control is so pointless.. If the road isn't sticky, all you do is burn out. I don't understand why they didn't set the launch rpm to 3500

[jphughan]

Haven't experienced it myself, but based on experiencing an E6x M6 in its harshest shift mode just under regular driving, I wouldn't be remotely surprised if that was normal. The M6 shifts combined the sound of the driveline grenading with the sensation of being rear-ended when the next gear engaged. I couldn't believe BMW had such a mode as a standard warrantied feature because I shuddered to imagine what was being done to the driveline.