My next car most likely will have DSG (same thing, dual clutch transmission). I’ve test drove cars with DSG and frankly, for most considerations, there is no way I can shift better than DSG in almost all situations. The drawback is when it comes to track day, I suppose it can be less fun, but I haven’t tracked a car lately. Plus it gives my wife the option to drive the car, who refuses to learn stick.
DCT is completely different SMG transmissions that BMW use to offer. SMG are sequential shifts, and the common complaint of SMG has been those are quite laggy in between shifts. DCT/DSG use two drive shafts, one hollow and one inside the other. Each shaft is responsible for engaging alternating gears, and at any point, one gear is always engaged on both shafts, with one shaft engaged to the engine. Shifting consists of switching from one shaft to the other, and for the next gear on the disengaged shaft to be selected. (Typical sequence from 1st to second: shaft 1 (with 1st engaged) is disengaged from engine, shaft 2 (with 2nd already engaged to shaft) is engaged to engine , and then 3rd is engaged on shaft one. Subsequent downshift into 3rd follows diseanging shaft 2 from engine, enaging shaft 1 (with third preselected), and enabling 4th on the second shaft, etc). Some fuzzy logic computer also monitors engine speed, your driving style, and supposedly is to adapt the transmission accordingly.
This design cuts down shift times down considerably and lag between shifts, shift times can be as low as <10ms. For most situations, people cannot shift quicker than some of these computer controlled DSG/DCT transmissions.
Drawbacks: these transmissions are much less smooth than your typical automatic (at least the first interation of DSGs that I drove). Second, they are expensive transmissions to maintain, should you ever need it serviced. Third, early versions of DSG/DCT could only handle a certain amount of torque. 4th, I hope you trust that german electronics when it comes to keeping a car for 10+years 🙂
DCT (BMW's name for it) really isn't new. VW/Audi licensed DSG transmissions from a company called Borg/Wagner and had an exclusivity on it. Since then, I believe the exclusivity expired, and hence why we're going to be seeing more DSG type trannies in other brands. There was other companies planning to build similar transmissions, Chrysler was going to be one of them (until they recently had contract problems with the supplier..Lawsuit pending).
VAG is now marketing DSG under the "s-tronic or r-tronic" label. Until recently, DSG transmissions were only available on cars with engines traversely mounted from VAG/Audi. IE: they were only available on TT's/A3's/Golfs/Jettas (and hence only available for fronttrak VAG products our Haldex AWD products from VAG. No option for torsen AWD systems). Until, recently, DSG has not been available on longitudinal mounted engines from VAG, and for that matter, means no DSG has been available on Audi's S4's/S6's/RS(which was only offered in stick anyway).
I believe the latest news is next generation of DSG trannies are going to be available on S4/S5's...Assuming you can even get an S5. Most are being sold overseas, where it can fetch more $ than here, especially with the slammed dollar. S5's are completely backlogged in the U.S. at most dealers and marked up so much over $8k, that it's now priced at the level of new M3's- which makes it a completely losing proposition. I'd take the M3, despite it's Bangled messed up E90 design.
S4's are suppose to be available soon, but they haven't announced when or if DSG is absoluately going to be available right away. Dealers are taking deposits though. There is supposedly an TT-S and TT-RS version in development, but it remains to be seen if they are going to make it stateside, due to the week dollar and because VAG has no U.S. factories to make them here.
I believe I read an article about Mitsubishi adopting a DSG type transmission in upcoming Evolutions. Likewise, I read Suburu is planning a dual clutch option for WRX's.
