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Discussion Starter #1 (Edited)
I'm off to the dragstrip again soon and wanted to re-gain some of that launch knowhow I'd likely forgotten from last year. To me, the trick (albeit obvious to some) to obtaining optimal 1/4 mile times for M5s is part tuning, part tires+temperature+track but equally as important is an optimal launch (this being the part where the driver really can make a difference on the day) because the rest of the run is more akin to being a passenger in a rollercoaster or something you can't otherwise influence.

I spent the past few hours tinkering with various approaches measuring only my 0-60 times, i.e. the launch. Ironically, I gave up using launch control because I could readily beat it by modulating the gas myself.

Personally, I find F10 M5 (S63TU) engines are a little slow to wind up from idle so I typically knock the transmission over into NEUTRAL before launching, I then rev the engine 4 or 5 times up to about 3,500rpms--this makes a difference in both feel and numbers in that the engine provides a much more immediate response--let it rev back down to idle and knock it back to S3 while it's coming down. Once it hits just below 1,000rpm, that's when I nail it.


The best run was achieved as follows:

  • transmission = S3
  • engine response = Sport Plus
  • suspension = Comfort
    • allows it to compress which resulted in a quicker launch
  • rear tires = Michelin PSS 295/30/20s
    • for track days, I typically deflate them by -2psi a tire
  • steering = Comfort
    • because the other settings are rubbish below 150mph
  • DSC = MDM or OFF
    • there was no difference between the two in terms of launch times
  • prime the engine with the NEUTRAL revving trick I mentioned above
  • floor the gas and be ready to short-shift
  • I lose traction somewhere around 4,500-5000rpms <-- this is when I intercede by pulling the paddle and shifting to 2nd
    • for me, if I hold 1st gear, the revs climb too high too fast and I hit the rev-limiter which screws any chance of a quick launch royally
  • make sure the pedal is fully in the carpet (through the detent)

For 0-60 runs, that's about it to achieve my best launch.

For full 1/4 mile runs, I typically knock the shift-lever back to D3 to let it handle the rest of the shifts so I can focus on steering without worrying about hitting the rev-limiter.

Here's the best launch I managed today (tires were 90 degrees F at the time):
 

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Very informative write up and great post!

I would be curious to hear other F10 mDCT owners' experiences on this as well.
 

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Company Representative of RPI Power
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Very nice detailed launch descriptions! I never give it that much thought, especially when you're in the moment. I definitely avoid launch control and sort it out myself. Good luck at the track! Let us know the results.
 

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Thanks for the post, a great write-up.
Could it be bad for the gearbox if its pushed to gear while the engine is still revving? (Well, while coming down from 3,500.)
 
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