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-   -   BMW M3 Double clutch transmission testing (http://www.motorworld.net/forum/showthread.php?t=55938)

fordgt84 04-25-2008 05:43 PM

BMW M3 Double clutch transmission testing
 
the good ppl from m5board have been busy testing out bmw's new double clutch gearbox... the vids are a bit long, but if you've got time they're quite interesting, enjoy :thumbup:

part 1

part2

hope it's not a stan again :bored:

5vz-fe 04-25-2008 05:48 PM

The VW DSG seems to be a faster shifter even tho both are dual clutch system.

styla21 04-25-2008 08:48 PM

Quote:

Originally Posted by 5vz-fe (Post 827728)
The VW DSG seems to be a faster shifter even tho both are dual clutch system.

Do you know what the official shift times are?

5vz-fe 04-25-2008 09:27 PM

^Nope...sorry. My comment is only based on video observation.

5vz-fe 04-25-2008 09:30 PM


styla21 04-25-2008 11:07 PM

Ok, so I did some research and i'm impressed! :-)

If we assume the time between shifts is calculated as
the time that the wheels are unpowered"
1.The VW system - "DSG" takes about 8 milliseconds to upshift.
2.The BMW system - "DCT" (Dual Clutch Transmission) - is stated as less than a tenth of a second.

So if we assume a maximum of 2 milliseconds difference, it is practically impossible for us to differentiate between the two. I wonder why the F1 teams aren't running this setup? :?:

They only drawbacks for using DCT's in production cars, apparently, is a higher production cost, and added weight (as a rough guide - 75kg, as opposed to 45kg for single clutch setup).
Also, if you want to select a gear that the system was not anticipating, it is very laggy (400ms) until that gear is engaged.

5vz-fe 04-26-2008 12:00 AM

I think Dual Clutch will be the way to go if you do not enjoy shifting it yourself but desire the directness and performance. In full automatic, it's quite impressively smooth.

yg60m 04-26-2008 08:27 AM

Thank you, very interesting videos :thumbup:

04RCSTI 04-26-2008 08:22 PM

Gaahhhhh Im going to be kicking myself for not buying that M3 pretty soon...

styla21 04-26-2008 08:38 PM

Quote:

Originally Posted by 04RCSTI (Post 827884)
Gaahhhhh Im going to be kicking myself for not buying that M3 pretty soon...

What did you buy instead? An STI?

Svensson 04-26-2008 09:38 PM

Quote:

Originally Posted by styla21 (Post 827757)
Ok, so I did some research and i'm impressed! :-)

If we assume the time between shifts is calculated as
the time that the wheels are unpowered"
1.The VW system - "DSG" takes about 8 milliseconds to upshift.
2.The BMW system - "DCT" (Dual Clutch Transmission) - is stated as less than a tenth of a second.

So if we assume a maximum of 2 milliseconds difference, it is practically impossible for us to differentiate between the two

A tenth of a second is still 100 milliseconds, so according to your data the DCT shifts 90 ms slower than DSG.

styla21 04-26-2008 11:52 PM

Quote:

Originally Posted by Svensson (Post 827888)
A tenth of a second is still 100 milliseconds, so according to your data the DCT shifts 90 ms slower than DSG.

Thanks Svensson. No idea how I mis-calculated that one!..:blink:

unwilling 04-27-2008 03:02 AM

Doesn't Ferrari's gearbox in the Scuderia take 60 milliseconds to shift?

turpija 04-27-2008 04:30 AM

Quote:

Originally Posted by styla21 (Post 827757)
.. I wonder why the F1 teams aren't running this setup? :?:

the McLaren announced they are working on a double clutch gearbox few years ago, I don't remember the exact number but I think they said that car would be on full throtle for 2 more seconds per lap then the standard sequential gbox which is a lot in F1, but I'm guessing the FIA pull'd the plug on that also, just like when Honda tryed to get the CVT gbox few years before that.

JoeHahn 04-27-2008 05:28 AM

Dual Clutch gearboxes are banned in F1 - its classed as having 2 transmissions.


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