BMW M3 Forum (E90 E92)

BMW Garage BMW Meets Register Search Today's Posts Mark Forums Read


Go Back   M3Post - BMW M3 Forum > M3 (E90 / E92 / E93) > General M3 Forum (E90 + E92 + E93)
 
GTB Performance
Post Reply
 
Thread Tools Search this Thread
      09-29-2009, 05:28 PM   #1
NetBoy
Private
4
Rep
89
Posts

 
Drives: 08 E90 M3
Join Date: Apr 2009
Location: Southeast

iTrader: (0)

Who's done the most DCT Launch Controls? Any problems?

Anyone done a lot of launch controls? Any issues (clutch, tranny) besides no rear tire tread

I'm wondering how the DCTs hold up. My old SMG fried the clutch at 40k miles and 10 launches. I know they are completely different systems but just curious.
Appreciate 0
      09-29-2009, 05:34 PM   #2
dillon733
Major
dillon733's Avatar
16
Rep
1,126
Posts

 
Drives: Jet Black e92 M3
Join Date: Oct 2007
Location: new york

iTrader: (2)

dont worry, the car is made to launch. I wouldnt do it every day of like 10 in the period of an hour but a couple times a month is fine. Make sure the location is safe then launch away!
Have fun be safe.
Launch Control FTW.
Appreciate 0
      09-29-2009, 09:28 PM   #3
boostitup28
New Member
0
Rep
20
Posts

 
Drives: AW E92 M3
Join Date: May 2009
Location: Park City

iTrader: (1)

I launched mine for the first time last night and did a pretty serious burn through the entire intersection. This morning i was sitting in traffic and basically not moving and that engine malfunction/reduced power warning came up and gave me all sorts of problems so now my car is in the shop getting the idle control valve replaced tomorrow. I doubt that the launch is the fault to all this but just my experience.
Appreciate 0
      09-29-2009, 10:41 PM   #4
KMIII
///M
KMIII's Avatar
United_States
15
Rep
403
Posts

 
Drives: 08 M-DCT E92 M3
Join Date: Apr 2009
Location: Houston, TX

iTrader: (1)

I would really like to know as well. Every time I think about LC, I think about how tough it would be on the transmission and all the different parts, so I refrain from using it. Think I should change my mindset?
Appreciate 0
      09-30-2009, 08:07 AM   #5
mkoesel
Moderator
United_States
183
Rep
13,842
Posts

 
Drives: 2015 SO/CSAT F80 M3
Join Date: Jun 2006
Location: Canton, MI

iTrader: (1)

I've probably used LC a couple dozen times or so.

Honestly, I doubt LC is that much harsher on the transmission than just flooring it in S6 with DSC off without using LC. I've done that a fair number of times also. Of course, that begs the question, just how durable is the DCT transmission in general. My feeling is that it is probably roughly as strong as the manual tranny car, and that the clutch-pack should last just as long as a manual transmission clutch as well. That's just my guess though.
__________________
A gen-u-ine BMW eff-eight-zero with them tandem clutches in the transmission and that dad gum sun roof on the top-a da cawr.
Appreciate 0
      09-30-2009, 08:14 AM   #6
quackbury
Master of the Obvious
quackbury's Avatar
1
Rep
178
Posts

 
Drives: X5 35D and 535ix M Sport
Join Date: Feb 2009
Location: New England

iTrader: (0)

My understanding is that some other manufacturers with launch control are denying warranty claims when the trannies need to be replaced. Forget if I saw the thread here or on another board.

It will be interesting to see how BMW handles it if/when frequently launched DCT's start blowing up......
__________________
Current:

2011 X5 35D Sport, DSB / Oyster
2011 535ix M Sport, TiAg / Black
Appreciate 0
      09-30-2009, 10:05 AM   #7
dcstep
Major General
United_States
65
Rep
5,036
Posts

 
Drives: '09 Cpe Silverstone FR 6MT
Join Date: Nov 2008
Location: Colorado

iTrader: (0)

Garage List
2009 M3  [4.00]
Speaking as a 6MT that routinely does 6 to 10 lauches at the average autocross, I don't see why it should be hard on the car so long as you're launching on average pavement with street tires. The 6MT will spin the wheels with what seems like very little stress on the clutch and then I modulate spin with the throttle. I don't see why the DCT would be any different.

I do remember reading that the DCT launches at like 5000 rpm. That's way too high for the 6MT, unless you ride the clutch or immediately back out of the throttle. If the DCT is slipping the clutch to make up for the ultra high rpm, then I'd probably want to launch with ESC off, in manual mode and control wheel sping with my foot, or let MDM control wheel spin. Slipping the clutch at that high rpm would be hard on the clutch if you did it back to back or even four or five times within and hour.

Those of you that have lauched your DCT, can you tell if wheel spin is controlled by the throttle or the clutch?

Dave
__________________
Appreciate 0
      09-30-2009, 11:37 PM   #8
Splinter4784
414 little horsies
Splinter4784's Avatar
Armenia
10
Rep
407
Posts

 
Drives: 2008 M3
Join Date: Jan 2009
Location: Beverly Hills

iTrader: (2)

Ive done around 20ish LC's
__________________
Race Precision Inc
Appreciate 0
      10-01-2009, 12:00 AM   #9
Dascamel
Lieutenant Colonel
Dascamel's Avatar
20
Rep
1,662
Posts

 
Drives: 2008 e92 M3, 2010 e91 328i
Join Date: Jul 2007
Location: Bakersfield, CA

iTrader: (0)

Quote:
Originally Posted by quackbury View Post
My understanding is that some other manufacturers with launch control are denying warranty claims when the trannies need to be replaced. Forget if I saw the thread here or on another board.

It will be interesting to see how BMW handles it if/when frequently launched DCT's start blowing up......
Thats on the Nissan GTR. Can't directly compare, it has far more torque and the car is AWD. The stress on the transmission and drivetrain is far more severe.
__________________
2008 E92 M3 Jerez Black,DCT,Fox Red ext,Prem,Tech,19", ipod/usb, CF roof and trim
2010 E91 328i Space Gray,Black int, M sport, most options
2007 Montego Blue 335i (retired)
Appreciate 0
      10-01-2009, 12:00 AM   #10
MysticBlue
Major
18
Rep
1,315
Posts

 
Drives: '09 M3 DCT Coupe, ---'15 x50i
Join Date: Apr 2008
Location: Eastern Oregon... They call 'em rigs here

iTrader: (0)

Quote:
Originally Posted by dcstep View Post

Those of you that have lauched your DCT, can you tell if wheel spin is controlled by the throttle or the clutch?

Dave
I think it's the throttle. When launch is initiated, it starts with quite a thunk... it doesn't feel like there is any clutch modulating going on at all. It feels pretty much like a clutch dump, then EDC controls wheel spin with the throttle just like it would doing a hard start without using launch control, except the intervention level is a whole lot less than normal EDC and a little less than MDM... in other words somewhere between MDM and nothing. I don't know this for sure, but that's my impression from the half dozen launches I've done.
Appreciate 0
      10-01-2009, 12:01 AM   #11
mixja
Captain
United_States
19
Rep
783
Posts

 
Drives: 2011 E90 DCT Silverstone
Join Date: Jun 2008
Location: Beverly Hils, CA

iTrader: (1)

Did mine properly for the first time about 4 weeks ago, ever since I've had a strange problem where the car makes a sound like it is hitting the rev limiter under WOT in 1st gear only. You can also pick the sound up sometimes on a bumpy surface in 2nd gear, so I think this is a DSC sensor issue or similar....
Appreciate 0
      10-01-2009, 10:04 AM   #12
dcstep
Major General
United_States
65
Rep
5,036
Posts

 
Drives: '09 Cpe Silverstone FR 6MT
Join Date: Nov 2008
Location: Colorado

iTrader: (0)

Garage List
2009 M3  [4.00]
Quote:
Originally Posted by MysticBlue View Post
I think it's the throttle. When launch is initiated, it starts with quite a thunk... it doesn't feel like there is any clutch modulating going on at all. It feels pretty much like a clutch dump, then EDC controls wheel spin with the throttle just like it would doing a hard start without using launch control, except the intervention level is a whole lot less than normal EDC and a little less than MDM... in other words somewhere between MDM and nothing. I don't know this for sure, but that's my impression from the half dozen launches I've done.

If you're correct, then I don't think that DCT launch should be too hard mechanically on the car. Electronically, I have no idea.

Dave
__________________
Appreciate 0
Post Reply

Bookmarks

Thread Tools Search this Thread
Search this Thread:

Advanced Search

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Forum Jump


All times are GMT -5. The time now is 02:04 PM.




m3post
Powered by vBulletin® Version 3.7.0
Copyright ©2000 - 2014, Jelsoft Enterprises Ltd.
1Addicts.com, BIMMERPOST.com, E90Post.com, F30Post.com, M3Post.com, ZPost.com, 5Post.com, 6Post.com, 7Post.com, XBimmers.com logo and trademark are properties of BIMMERPOST