[dxb335d]

Originally Posted by mwahlert

you can't brake boost a dct..

and why is that?

Dougie seems to think you can.

[Serjames]

nice vid Dougie !

Wonder how the Launch control would work with the Quaife on as it looks like lots of wheel spin still occurs ?

SJ

[Dougie335]

dxb,
I don't think I ever said you could brake boost! Anyway at the start when I could not get the LC to work I did do what you call brake boost. All that happens is the revs go to approx 1300-1500 and the car tries to pull away. The revs will not go above this level even with the throttle held at full. Its only when you activate the pressure point beyond full throttle and you are set-up for LC does the revs then go to 4800 for the launch.

I have put up a load of graphs show different launch conditions here if you want a look:

http://www.e90post.com/forums/showthread.php?t=256829

Dougie.

[5soko]

Nice video!

[dxb335d]

an 1800 launch is brake boosting lol

[Driver72]

Originally Posted by Dougie335

dxb,
I don't think I ever said you could brake boost! Anyway at the start when I could not get the LC to work I did do what you call brake boost. All that happens is the revs go to approx 1800 and the car tries to pull away. The revs will not go above this level even with the throttle held at full. Its only when you activate the pressure point beyond full throttle and you are set-up for LC does the revs then go to 4800 for the launch.

I have put up a load of graphs show different launch conditions here if you want a look:

http://www.e90post.com/forums/showthread.php?t=256829

Dougie.

That absolutely BLOWS.

So with DCT you have a choice of either using the "launch control" that is sub-par for achieving optimum acceleration times with it's bog, spin, bog, then go outcome, OR you have a limit of 1800 rpms on the brake boosting. Which for a tuned 335i is plenty on street tires or most strips, but on really well prepped strips on DR's or something, 1800 rpms would not be sufficient either to getting optimum times.
to BMW for it's sub-par LC and limiting brake boosting to 1800 rpms (should be like 2200 rpms).


Note to BMW, please see GM's launch control video/data on their 2010 ZO6 Vette for how to program you DCT launch control please. Make the needed changes for the 2010 335i's DCT equipped cars software program please!

[mwahlert]

brake boosting a dct is like holding the clutch half way out on a manual transmission - holding the car in place with the e-brake and applying throttle.

the car won't let you brake boost because a its not really possible as you will stall the engine - and b) it would ride the living hell out of the clutch disk...

remember - a dct does NOT have a torque converter that allows for engine slip vs. trans w/o wear..

[Vtec Abuser]

Originally Posted by G33

M3 needs to be in the hands of a really good driver to make it 'go'!

Totally agree mate.. Revvy engine that needs to be driven 100% (especially if manual). It's a lot easier to get 100% out of a auto TC 335 than it is a manual M3..
Just need to look at what terminals the E92 M3's are doing at Pod to know they are quick once off the line (112mph+)..
Also there is a few vids here of a DCT M3 v's a well tuned 135i
135i has...
JB3 with 1.22 map
RR catless downpipes + exhaust
Quaife LSD
KW level 2 suspension
M3 standard..

Decent vids and considering the 135i will be running similar (if not more) power as the M3 the M3 doesn't do to bad..

[E93TM]

this is odd i try this and my rpms stay idle between 1000-1200 even with DTC off, sport mode, and ive tried it in both manual and auto so i checked online and apparently bmw has designed a system where if the ecu detects that the transmission is too hot it cuts power to avoid damage to transmission or engine but this is just strange because it should only do this if you do multiple times. however with my car i cant even get the checkered launch control flag my back wheels just feel locked up does anyone know what the issue could be is it my suspension, is it the car or am i doing something wrong.