7-speed – rpmGo.com

The official announcement of the new BMW M3 Convertible, BMW introduced another premiere, the M DKG seven-speed double clutch transmission. The system has been developed by BMW’s M division and it will be available for all the new M versions: Coupe, Cabrio and Sedan.

The new M double-clutch transmission features BMW’s Drivelogic technology and allows faster gearshifts, resulting in faster acceleration times (from 0 to 100km/h in 4.6 seconds – 0.2 seconds faster than the manual six-speed version) and better mileage (average fuel consumption of 22 mpg or 11.9 litres/100 km).

The new transmission is the world’s first seven-speed double-clutch gearbox developed for a high-torque, high-speed powerplant and offers eleven driver-selectable electronically controlled driving program choices. I’m guessing the manual for this isn’t quite an easy read.

The system “acts to smooth out gearshifts to the point that they are often only discernible by watching the rise and fall of engine rpm on the M3’s tachometer. Each oil-cooled wet clutch activates its own set of ratios – one is used for first, third, fifth and seventh gears, as well as reverse, while the other looks after second, fourth and sixth gears.

Gearshifts are effected by the disengagement of one clutch and the engagement of the other, moving seamlessly from the ratio in use to the next, preselected ratio.The fact that the next ratio is preselected and engaged merely by activation of the clutch is the secret behind the amazingly smooth and efficient transition from gear to gear.”

To fully understand how this works, read the full press release after the jump.
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Post tags: Tags: 7-speed, BMW, bmw-m3, bmw-m3-cabrio, bmw-m3-convertible, bmw-m3-coupe, bmw-m3-sedan, double-clutch, gearbox, transmission