BMW makes double-clutch tranny for M3 V-8s

BMW offers a new, double-clutch transmission on its 2009 M3 Coupe, Sedan, and Convertible models.

2009 BMW M3
The new BMW M3 gets a dual-clutch transmission option. CNET Networks

BMW announced today that it will make a new double-clutch transmission available on the 2009 M3, the sport-tuned version of its 3 series. A double-clutch transmission is really a manual transmission, but can be used like an automatic. Instead of requiring the driver to push a clutch pedal, the car's computer and actuators control two clutches. When the driver selects an upshift or downshift, the system engages one of its clutches and disengages the other, making shifts faster than a traditional manual. BMW previously developed its SMG, or sequential manual gearbox, which operated like a double-clutch transmission from the driver perspective, but it was largely decried as difficult to use under normal driving conditions.

The new transmission uses technology similar to that of Audi's Direct Shift Gearbox, or DSG, a transmission that we've seen in a number of Audi models and enjoyed immensely. But Audi doesn't offer the DSG on any car with more than a V-6 engine because, we assume, the DSG can't handle the torque. The DSG can also fail if it gets too hot, as we've seen a DSG-equipped GTI get pulled from the track after about a half day's worth of laps due to this problem. BMW's new transmission is designed to handle the M3's fast-revving V-8 and has a separate cooling system intended to make it impervious to overheating. In the M3, the double-clutch transmission gets seven gears, one more than the DSG, and uses a system called DriveLogic by BMW to determine shift points. The driver will be able to choose from Drive mode, or automatic shifting, and Sport mode, where the driver will choose when to shift. In addition, the driver can choose from five driving programs in Drive mode and six programs in Sport mode, tailoring the shift points and responsiveness to different conditions. The new transmission will be available on the M3 Coupe, Sedan, and Convertible.

About the author

Wayne Cunningham reviews cars and writes about automotive technology for CNET. Prior to the Car Tech beat, he covered spyware, Web building technologies, and computer hardware. He began covering technology and the Web in 1994 as an editor of The Net magazine. He's also the author of "Vaporware," a novel that's available as a Nook e-book.

 

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