BMW M3 Double clutch transmission testing

[fordgt84]

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

part 1

MBOARD.com test of BMW M3 E92 DKG DCT Double Clutch 1/2 - YouTube

MBOARD.com test of BMW M3 E92 DKG DCT Double Clutch 1/2 - YouTube

part2

m3e90board.com test of BMW M3 E92 DKG DCT Double Clutch 2/2 - YouTube

m3e90board.com test of BMW M3 E92 DKG DCT Double Clutch 2/2 - YouTube

hope it's not a stan again

[5vz-fe]

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

[styla21]

Originally Posted by 5vz-fe 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]

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

[5vz-fe]

R32 DSG Launch Control - YouTube

R32 DSG Launch Control - YouTube

[styla21]

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]

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]

Thank you, very interesting videos

[04RCSTI]

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

[styla21]

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

What did you buy instead? An STI?

[Svensson]

Originally Posted by styla21 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]

Originally Posted by Svensson 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!..

[unwilling]

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

[turpija]

Originally Posted by styla21 .. 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]

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