05dsom

Hi,

I was reading some of the latest car mags and it got me to wondering what's the fastest shifting "manumatic" or "semiautomatic" "dual clutch automatic" or whatever transmission...Porsche PDK, Ferrari F1, BMW SMG, Audi DSG, Lexus 8speed etc..

anybody know?

Some are very close to the speed of Formula 1 transmissions I think?

Dueysan

Beats me but we have the DSG in a 2009 Volkswagen GTI and believe the shifts are less than 1/10th of a second....great transmission but it's maintenance costs will be far higher than a hydraulic slushbox.

Guibo

Ferrari DCT (in the 458): 50 milliseconds according to this
http://www.autoexpress.co.uk/carrevi...58_italia.html

Ferrari's F1 car: 40ms
F430 Scuderia (single-clutch): 60ms
http://www.insideline.com/ferrari/45...rst-drive.html

Porsche PDK: <200ms
http://www.autocar.co.uk/CarReviews/...arrera/211024/

Various sources put BMW's M-DCT and VW's DSG at 8ms (vs 80ms for the old BMW SMGII system), but I find it hard to believe they would be that much faster than Ferrari's system, so maybe all of these manufacturers are using different standards. I don't think there's an official standard to measure what constitutes gearshift speeds (like SAE net hp), and upshifts and downshifts appear to have different times too. And because DCTs effectively transfer torque almost seamlessly due to the next gear being pre-selected, we can't really compare DCT shift speeds to automated single-clutch gearchanges.

Dave68

You got that right! That's why I don't recommend certain vehicle purchases when the warranty had expired. A former coworker spent $7000 for a clutch replacement and various other things for his 2002 Boxster.

JerriVette

I hope the upcoming C7 corvette has the option of a dual clutch...as I want the consistancy and speed this new technology offers..

Its the future of high performance vehicles and I will have it in my next vehicle...after my manual C6 Z51 and previous c5 Z06.

Dual clutch technology is just too consistant and too fast to pass up on.

JMO

PeterK

The 02 boxster does not have a dual clutch tranny and it had to a lot of
"various other things" since a clutch job on this vehicle typically runs <$1K at an indy place.

PeterK

Is it? My friend has an Audi A3 with a DCT. He already has over 100K on the clock and the tranny hasn't presented him with any issues ... unlike the rest of the car.

Racer86

Ok, I'll try,,,,, 1, 3, and 5 gears are on one input shaft and clutch. 2, 4, and 6 on on the other input shaft and clutch. The transmission has a concentric dual inputshaft,, one shaft running inside the other. one clutch is connected to each separate shaft. The gears are constant mesh, and are engaged to the correct shaft, At the shift event, the ecu picks one clutch to engage and the other to disengage at each shift. computer timing of the clutch's release/ engage event of each clutch is very fast, and much closer than human control.
hope this helps

chunnydave

So, for example, when the transmission is about to shift out of 2nd, 3rd gear is waiting to go on another shaft? If so, what happens on the way down?

MVR 155

Exactly the opposite, basically all gears are spinning and "on deck", on the downshifts the computer matches the revs and downshifts just about as quickly as it upshifts.

Racer86

yep! correct

05dsom

well, I do know how they work, I asked which is FASTEST

Itiner

one of the best dual clutch semi automatic is in the GT-R /nissan/ and there is another great unit in the Mitshubishi Evolution MR.
You can argue which is better , example the BMW or VW or Mitshubishi etc. But and of the day most of them build by Getrag.
So its a same quality unit. If you want to know more here is the direct link to the forum /EVo/ and read they impressions about it.
http://forums.evolutionm.net/mitsubi...ed-models-307/

here is the getrag link:
http://www.getrag.de/en/216

and to make the story short , they are nothing close to the F1 transmissions, not even the WRC .

Rob

JerriVette

Great technology that I hope makes it to GM products in general and the corvette c7 ..at least as an option.

Just too dam fast and consistant to not want.

IMO

MVR 155

While I have driven a few different cars with Dual Clutch trannies..... I had the opportunity to drive the 2011 M3 with DCT at the Autobahn country club north track this weekend, the trans is absolutely amazing offering instantanious, firm and lightning fast up shifts and instant rev matching downshifts when called for. Dual Clutch technology is definately where its at if you are going to opt for a 2 pedal car.