Twin-clutch pioneer Audi is now the proud manufacturer of a new 7-speed twin-clutch gearbox called S Tronic. Joining Audis other offerings like 6-speed DSG, Multitronic, manual, Tiptronic and R Tronic, S Tronic is another step forward in the pursuit of high performance, lower fuel consumption and satisfying driving experiences.
The S Tronic is capable of attending to up to 550Nm of brute torque, and handling engine speeds of up to 9,000rpm. This probably explains why the [Nm RS 6] uses a normal 6-speed Tiptronic transmission.
S Tronic is a twin-clutch transmission system that, you guessed it, uses two clutches to engage and change gears. The gist of it is that while other systems only engage the next appropriate gear when the control unit decides speed, revs and throttle are optimal for that action, twin-clutch systems work a little faster. These engage the next gear as soon as the current gear is engaged, thus in essence lie in wait for the action to be approved so as to quickly slip into engaged selected gear. Simple.
S Tronic can also be driven in various modes, such as D (Drive) and S (Sport). In normal D mode drive changes are auctioned by the computer, while S allows for quicker shifts that can even be done via optional rockers behind the steering wheel.
.. and if you cba to read all that...
The S-tronic and DSG are the same thing as far as VW/Audi goes and it is simply known as S-tronic. It's a twin clutch, sequential auto/manual. Supposedly can change gears in .02 seconds. And thought to be the second most advanced gearbox, behind only Ferrari.