Sequential Shifter Speeds Up New Bmw M3Mixing sedan practicality with supercar performance has made the BMW M3 one of the world's most desirable cars. Now, a new sequential-shift gearbox makes it even better. Inspired by circuit racing and developed by BMW's elite "M" division in concert with Getrag, the '97 Euro-spec M3 SMT is the first six-speed sequential shifter to go into production, and the first based on a manual gearbox.
While broadly similar systems, such as Porsche's Tiptronic or BMW's own Steptronic, are linked to automatics, the M3's Sequential M Transmission (SMT) is almost identical in design and structure to a manual. That means no torque converter-and no resultant "slip" losses. The M3 SMT has neither a clutch pedal nor a conventional shift gate; instead, its shift lever operates through one of two planes. In the right-hand plane, it must be placed in Neutral for the engine to fire up. A forward push grabs Reverse, and pulling it back to the "Economy" setting allows the SMT to self-shift like an automatic.
Slide the lever into its left-hand "Sport" plane, and the fun begins: Push forward to downshift and pull back to upshift-changes come as fast as you can move your hand. Movement of the lever hydraulically actuates the clutch, and you can upshift even with the 3.2-liter/321-horse straight-six screaming gloriously at redline and the gas pedal buried deep in the carpet
The transmission's electronic control unit retards the ignition or briefly cancels out one of the cylinders during any flat-footed upshifts. It's the smartest such system yet seen on a street car, exchanging information with the engine's ECU up to 100 times per second, and issuing instructions at the rate of 20 million per second. This allows the driver to slide up or down several ratios at a time, secure in the knowledge that the SMT will never select a gear low enough to overrev the engine.
And the shifter flatters with the sweetest downshifts imaginable, blipping the throttle by precisely the required amount at precisely the right moment.
Even the most capable drivers will find that the Sequential M Transmission gives back more than it takes away, with improved performance through consistently faster gear changes, greater comfort through smoother downshifts and the lazy-days auto option, and higher levels of active safety (and engine protection) through the impossibility of selecting a wrong gear. That an M3 SMT is also quicker on twisty roads than its stick-shift equivalent and is liable to leave you smiling for hours after is, of course, just a happy coincidence.
The M3 SMT goes on sale in Europe next spring as a late '97 model. No intro date has been confirmed for the U.S., but based on previous BMW history, we'd expect to see it here within 12 months.
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