launching problem with DCT E92 335i

marklim · 01-17-2009, 09:55 PM

Not sure if many of you are aware about it, but the new DCT E92 335i does not allow us to brake boost as usual. Experiments that i've tried with my DCT 335i.

1) DTC-On DSC-Off / Gear "D" / Accelerate until right before WOT
http://www.youtube.com/watch?v=7UMfzuZoeC4

2) DSC-On / Gear "D" / Accelerate until right before WOT
Same as above

3) DSC-On / Gear "M1" / Accelerate until right before WOT
Same

4) DCT-On DSC-Off / Gear "M/S" / Sports Mode / WOT = Launch Control
In this mode, Launch control is activated and launches pretty quickly for
a STOCK DCT 335i.

However, after JB3, Procede, or any other upgrades, Launch Control is pretty useless as the car has too much power for the wheels to grip and its pretty much spinning all the way. Also, we cant fiddle with the rpm as it will drop back down to around 900rpm after 0.5 secs of stepping on the accelerator.

So, anyone out there with a solution to launch a tuned 335i ?

Cheers,
Mark

Driver72 · 01-19-2009, 07:26 PM

So let me get this straight:

If you try to put one foot on the brake and one on the accelerator and bring revs up any higher than about 1200 rpms DCT goes into a protected mode and drops the revs back down to idle?

And the only way to bring the revs up higher is to initiate launch control?

However, with a tune on the car, and initiating launch control the launch control basically does not work and allows the tires to spin uselessly?

And any attempt to "alter" the launch control revs (meaning not flooring the throttle to bring the revs down a bit lower than what launch control automatically brings it up to) and within 1/2 second returns the car to idle.

Did I get that correct?

If so, wow, good to know, guess I wouldn't be paying the extra couple grand for DCT then on my next BMW but rather stick with the tried and true 6AT.
Or, hopefully the tuners will figure away around the DCT launch control program too and allow you to launch the car under lower revs or at whatever revs YOU choose, not the program.

Good luck

marklim · 01-19-2009, 09:47 PM

Yes. Exactly. Thanks for putting it in english for me. Haha.

I too, hope that tuners can do something about it.

Cheers,
Mark

HP Autosport · 01-22-2009, 01:40 AM

Quote:

Originally Posted by marklim

However, after JB3, Procede, or any other upgrades, Launch Control is pretty useless as the car has too much power for the wheels to grip and its pretty much spinning all the way. Also, we cant fiddle with the rpm as it will drop back down to around 900rpm after 0.5 secs of stepping on the accelerator.

So, anyone out there with a solution to launch a tuned 335i ?

Cheers,
Mark

Install a Quaife ATB LSD?

marklim · 01-22-2009, 09:33 AM

Quote:

Originally Posted by HP Autowerks

Install a Quaife ATB LSD?

would that help ?

HP Autosport · 01-22-2009, 02:43 PM

Quote:

Originally Posted by marklim

would that help ?

It will certainly help you off the line. You won't be spinning one tire only and overall traction will be improved.

Driver72 · 01-22-2009, 04:49 PM

On a side note, no doubt a true LSD will help.
But keep in mind, only the very early 335i's really spin just one tire.
As of March 2007 build they started the e-LSD in the cars.
It's no TRUE LSD, but without a doubt it helps and I've noticed that especially when going perfectly straight, you will often spin both tires with the e-LSD too.
But often one still spins a bit more than the other, so a true LSD will help a bit.

However, I don't think it would be enough.
What he needs is to be able to lower the revs in launch control mode so the extra power of the tune can be controlled a bit more and the car isn't launching like if it had stock power still.

01-17-2009, 09:55 PM	#1
marklim Private First Class 21 Rep 147 Posts Drives: E92 Join Date: Aug 2008 Location: Singapore iTrader: (1)	launching problem with DCT E92 335i Not sure if many of you are aware about it, but the new DCT E92 335i does not allow us to brake boost as usual. Experiments that i've tried with my DCT 335i. 1) DTC-On DSC-Off / Gear "D" / Accelerate until right before WOT http://www.youtube.com/watch?v=7UMfzuZoeC4 2) DSC-On / Gear "D" / Accelerate until right before WOT Same as above 3) DSC-On / Gear "M1" / Accelerate until right before WOT Same 4) DCT-On DSC-Off / Gear "M/S" / Sports Mode / WOT = Launch Control In this mode, Launch control is activated and launches pretty quickly for a STOCK DCT 335i. However, after JB3, Procede, or any other upgrades, Launch Control is pretty useless as the car has too much power for the wheels to grip and its pretty much spinning all the way. Also, we cant fiddle with the rpm as it will drop back down to around 900rpm after 0.5 secs of stepping on the accelerator. So, anyone out there with a solution to launch a tuned 335i ? Cheers, Mark
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01-19-2009, 07:26 PM	#2
Driver72 Brigadier General 327 Rep 4,484 Posts Drives: 335i - to new owners now. Join Date: Dec 2006 Location: California iTrader: (0)	So let me get this straight: If you try to put one foot on the brake and one on the accelerator and bring revs up any higher than about 1200 rpms DCT goes into a protected mode and drops the revs back down to idle? And the only way to bring the revs up higher is to initiate launch control? However, with a tune on the car, and initiating launch control the launch control basically does not work and allows the tires to spin uselessly? And any attempt to "alter" the launch control revs (meaning not flooring the throttle to bring the revs down a bit lower than what launch control automatically brings it up to) and within 1/2 second returns the car to idle. Did I get that correct? If so, wow, good to know, guess I wouldn't be paying the extra couple grand for DCT then on my next BMW but rather stick with the tried and true 6AT. Or, hopefully the tuners will figure away around the DCT launch control program too and allow you to launch the car under lower revs or at whatever revs YOU choose, not the program. Good luck
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01-19-2009, 09:47 PM	#3
marklim Private First Class 21 Rep 147 Posts Drives: E92 Join Date: Aug 2008 Location: Singapore iTrader: (1)	Yes. Exactly. Thanks for putting it in english for me. Haha. I too, hope that tuners can do something about it. Cheers, Mark
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01-22-2009, 04:49 PM	#7
Driver72 Brigadier General 327 Rep 4,484 Posts Drives: 335i - to new owners now. Join Date: Dec 2006 Location: California iTrader: (0)	On a side note, no doubt a true LSD will help. But keep in mind, only the very early 335i's really spin just one tire. As of March 2007 build they started the e-LSD in the cars. It's no TRUE LSD, but without a doubt it helps and I've noticed that especially when going perfectly straight, you will often spin both tires with the e-LSD too. But often one still spins a bit more than the other, so a true LSD will help a bit. However, I don't think it would be enough. What he needs is to be able to lower the revs in launch control mode so the extra power of the tune can be controlled a bit more and the car isn't launching like if it had stock power still.
	Appreciate 0 Quote