We like VW-Audi's twin-clutch automated manual transmission. We like it a lot. But so far, it's been available only on transverse-engine cars such as the VW GTI, Audi TT, and A3. That's not enough.
At present, the longitudinal-engine Audis -- from A4 up -- get either a manual, or a regular tiptronic auto (for the quattros) or the Multitronic CVT (for the FWD cars). Yeah, we get confused, too. Especially when VW calls its twin-clutch system DSG and Audi prefers the name S-Tronic.
Anyway, we like it, and we'd like it even more in a more powerful car. Which is where the longitudinal engines come in. Audi has now taken the S-Tronic principle and set about building an all-new tranny to do the same job behind the V-6s and V-8s of the bigger cars.
We recently sneaked a drive in a prototype fitted with Audi's newest S-Tronic. It was the 354-horsepower S5 quattro, a car that deserves a quick-acting, column-paddle-operated, seven-speed transmission that never interrupts the flow of power. Now it has one.
The new seven-speed has a maximum torque capacity of just over 400 lb-ft. This means it can cope with even the V-10 in the S6 and S8, though whether those cars will actually get the new transmission before their lifecycles end is uncertain.
In fact, it'll arrive first in the Q5 compact sport/utility, which will make its global launch at the end of 2008. Shortly thereafter, the new seven-speed will get plugged into multi-cylinder editions of the A4, A5, and S5.
In D mode, the new transmission behaves pretty much as a torque-converter auto. The clutches have been programmed to give a little creep when you come off the brake pedal at idle. It's not perfectly liquid, no, but it'll suffice. And continuing up and down the speed range, it really does feel like an auto -- albeit one that uses its lock-up clutch all the time.
This direct connection between gas pedal and wheels is what makes the unit feel so sporty. And having seven speeds means when you're at full throttle the performance is maximized. On the other hand, when you're cruising and need to wake things up by a kickdown, you can get greeted by a stutter if the thing decides to shift down two ratios.
Switched to tip mode, the direct relationship between pedal and wheels makes even more of itself. You have a much tighter connection with the car than a slushy auto can ever give, as you meter the wheels' efforts to a fare thee well. Especially in corners.
And arriving at those corners, using the paddle to pop down through the gears while keeping a steady foot on the brake and both hands on the wheel, is a pleasure we'll never tire of.
The twin-clutch system works like this: One clutch controls gears 1, 3, 5, and 7 while the other deals with 2, 4, and 6. Say you shift up to 3, the unit then preselects 4, with that clutch open. When you call for 4, the even-number clutch closes and simultaneously the odd clutch opens. And here comes the only glitch. When it's expecting you to call for 4 and you actually ask for 2, there's a short pause while it reshuffles itself. But honestly you seldom notice.
I remarked to the transmission's development chief, who sat alongside as I drove, that the unit in the R8, a single-clutch AMT, really wasn't a match for the new S-Tronic. He nodded in agreement. It's only a question of time before the R8, the best everyday supercar, will get this, the best everyday transmission.