The gearbox also keeps the F1 style gearbox's benefits. Because the computer will change gear very precisely, and not over stress the components, the weight of the whole unit is not much more than a conventional gearbox and clutch. This is because the parts can be made to much tighter tolerances, but still manage the same life expectancy as the manual counterparts.
There is a downside to the gearbox though: it cannot be used in races. This is because it changes gear so quickly, and the loss of drive is so minute, that the gearbox gets classed as a Constantly Variable Transmision. The FIA and other governing bodies outlawed this in the early 80s. However, with the speed that some of the current Formula One cars can now change, this may be altered. The current Honda gearbox is called the 'Lossless' gearbox after all, but they did prove that it reduces engine power and its use was therefore allowed.
The crowning achievement of the DSG is the English-made, Ricardo Company's seven speed DSG, for use in the Bugatti Veyron. That particular car is worthy of its own - more detailed - article, so that will have to wait.
So, next time you drive a DSG car just think: You can change gear faster than even the Formula One and Indy drivers.
Special thanks to Audi for the images and the link to the video demonstrating the gearbox in action.
Article comments
1 - Michael Karesh
Perhaps the best explanation of the DSG I've come across. Excellent job.
2 - Tony
Very good article, but still haven't seen explanation on how DSG operates from standing start - Electronic controlled engagement of conventional clutch in first gear? Does this mean clutch is being continuously 'slipped' when in Drive but at standstill with brakes on? Does this not lead to increased clutch wear for the clutch that includes first gear?
3 - Ashleigh
That's correct, it's basically the same as when manual car drivers slip it during a hill start etc. Obviously the car can use it's brakes etc to compensate so the wear is actualy lower than conventional clutch.
The DSG is being re-invented soon as well. VW have announced a 7 speed, dry clutch system capable of handleing 450ft/lb torque that will be launched soon.
4 - Carl
Thank you for a very helpful article. However, when I read the published mpg figures (here in the UK) there seems to be an up to 10% fuel consumption penalty associated with a DSG gearbox. Granted that's better than the apparent 15-20% of a traditional automatic. But why the apparent 10% penalty?
5 - Ashleigh
It's mostly down to the extra weight of the DSG 'wet' box. The newer dry clutch boxes should get the penalty down a bit more.
However manufacturers figures are for an ideal manual driver, and the DSG is always going to perform the same, so in reality the difference is negligible at best.
6 - lawrence ogden
the dsg box is brilliant i have a glof tdi 170 dsg and can get 54 mpg on a run (19km/litre) it is the best auto box ever put in a car the gearchange is seamless dont bother using the paddles put it into drive and enjoy the ride if you use sport mode it holds on to 5th gear to 115 mph.tdi170gsg is one of vw`s best kept secrets
7 - LT
That's correct, it's basically the same as when manual car drivers slip it during a hill start etc. Obviously the car can use it's brakes etc to compensate so the wear is actualy lower than conventional clutch.
I doubt the wear is lower since either car can use the brakes. The difference is in a manual transmission the driver disengages the clutch. With a dsg when stopped at traffic lights for example the clutch is still dragging and you can feel this as the load is eliminated if you shift to neutral. It will be interesting to see just how long the clutch lasts in a dsg compared to an experienced driver with a conventional transmission.
8 - Federico Melo
I just bought a 2.0 T FSI with DSG and realized about the charge being applied though odd clutch when standing stop in drive mode and can’t believe it. Besides the obvious feeling, I checked it by watching instant fuel consumption increasing when switching from neutral to drive or first. I only can think that wear is so low that VAG group thinks is better, because it would be extremely easy to fully release clutch when detects speed zero and brake applied. Even if they assured that wear is minimal I would prefer full release and I think I’ll get use to place it into neutral while waiting for light or traffic to move.
9 - Ashleigh
Remember most of them are wet clutches, so wear isn't that high.