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      07-25-2007, 03:17 AM   #91
swamp2
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Drives: E92 M3
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Quote:
Originally Posted by esquire View Post
as i remember it, part of the issue with SMG launch control was the distance separating the gears in the gearbox. gears 1 and 2 were on completely opposite ends of the gearbox, resulting in gear changes which were incrementally slower than a manual through the early gears. see the attached picture. BMW's reasoned that by placing the highest load bearing gears (1, 2 and R) in the most stable part of the gearbox - the corners - the transmission would operate more effectively. .

i don't know that M-DCT would suffer from this same ailment, given that the dual clutch system always holds the next gear in reserve, ready to be engaged. If this is the case, the distance between gears would become irrelevant, and M-DCT launch control would outpace SMG's. Thoughts and feedback welcome.

- esquire
M3onTwomps: SMG II in the M3 was not the same layout the the SMG III in the M5. The M3 unit was a traditional pattern 6 speed box, modified with the hydraulics to move the lever just as a person would. Since the M5 was (initially) designed to be only SMG they could afford to deisgn the box specifically for SMG and gain other benefits while scrapping the need for a traditional gate pattern.

Also the launch control software and the 1-2 shift are totally unrelated. The launch control and crippled LC we seem to get in the US is the software that holds the revs, dumps the clutch, and possibly moderates clutch, throttle and anti-spin controls to achieve the best possible launch. It is almost all software and unfortunately the software in the M3 SMG II was not as talented as the best drivers. Granted much more consistent and better than most drivers but not all.
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