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      09-18-2007, 10:41 AM   #1
stefano7171
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info on the M3 7 speed dual clutch gearbox

http://www.getrag.de/455
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      09-18-2007, 11:18 AM   #2
JEllis
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thanks for the link
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      09-18-2007, 11:20 AM   #3
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that looks weird. how come 1,2,3 have dual cone, then 4,5 have single cone, then 6, 7 have dual, then reverse has single?!

that's strange...
i assume one of the clutches takes care of 1, 3, 5, 7? and the other does the rest? which does the reverse?

but the most important question is who cares about the answers to my previous questions?!
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      09-21-2007, 09:16 PM   #4
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good questions... and what does this....

Quote:
While one gear is engaged, the system has already preselected the next.

...mean for the driving experience? Slower response to shifts the system did *not* expect? i.e. the system expects upshift but you downshift.. resulting in a less-than-instant downshift? curious... I have no experience with a gearbox like this....
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      09-22-2007, 01:50 PM   #5
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Quote:
Originally Posted by Hans Delbruck View Post
good questions... and what does this....




...mean for the driving experience? Slower response to shifts the system did *not* expect? i.e. the system expects upshift but you downshift.. resulting in a less-than-instant downshift? curious... I have no experience with a gearbox like this....
That's exactly what it means.

You will have to "rewire" you brain to anticipate the need to downshift and "tip" the transmission down several times until you get the gear that you want at least a second before actually needing it.

In DSG manual mode, for example, I tap twice from 6th to go to 4th if I'm slowing down to turn ahead in the city. By the time I get to the actual turn the DSG itself will downshift to 3rd (depending on the speed and revs it can stay on 3rd or go to 2nd by itself) and I tap again to 2nd to get some power ready to get out of the turn if necessary. You can leave the DSG alone and it will downshift all the way to 2rd (again, depending on the speed and revs) as you slow down for the turn, but I don't like how much time it takes to go to 2nd by itself, so I help it a little bit by downshifting early to 4th or even 3rd like I use to do anyways driving my manual M3. Depending of the turn itself and the speed entering it I decide if the tap to 2nd is necessary or not.

I still learning new ways of driving in manual mode (95% of the time) to be close as possible to the way I drive a manual transmission. The upshifts are simply better than any manual transmission that I've ever driven, fast, smooth, strong. The downshifts without any anticipation are the worse.

I expect the M-DCT to be a much better system than the current DSG just by two features: the wet clutches and the 7 speed (both features are coming to the DSG also). Of course, the best feature will be marrying this transmission with a high revving V8 and with all the techo-tricks of BMW. I think that the downshifts timing will be better taken of in the M-DCT just because of the lessons learned with the DSG
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      09-23-2007, 12:31 PM   #6
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Good info thanks for the url...
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      09-23-2007, 12:35 PM   #7
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Quote:
Originally Posted by Hans Delbruck View Post
good questions... and what does this....




...mean for the driving experience? Slower response to shifts the system did *not* expect? i.e. the system expects upshift but you downshift.. resulting in a less-than-instant downshift? curious... I have no experience with a gearbox like this....

DCT is really fast because it already *expects* your next gear and makes it ready for you before you shift. This will allow response as fast as 8 millisecond to shift (Enzo's tranny shifts in 150 millisecond, just so you can compare)

BUT if you do something different, like slow down instead of pushing gas or something it it will take up to half a second to re-select a new gear.

there used to be a wiki but i cant find it anymore
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      09-23-2007, 12:56 PM   #8
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Quote:
Originally Posted by Hans Delbruck View Post
good questions... and what does this....




...mean for the driving experience? Slower response to shifts the system did *not* expect? i.e. the system expects upshift but you downshift.. resulting in a less-than-instant downshift? curious... I have no experience with a gearbox like this....
http://video.google.com/videoplay?do...45337871038412
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      09-23-2007, 01:22 PM   #9
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Good, but

Quote:
Originally Posted by stefano7171 View Post
A huge . This has been extensively discussed in other forums.

As have most of the questions raised in subsequent discussions.
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