First Double-Clutch Transmission That Can Handle 9000 RPM
Available as a $2700 option on all M3 coupes, sedans, and convertibles, M DCT is the first double-clutch transmission that can handle engine speeds up to—thank you, BMW—a screaming 9000 rpm. M DCT adds about 45 pounds, according to BMW; our 3630-pound test car weighed in 30 pounds heavier than our last manual M3 coupe.
The M DCT uses two oil-cooled, wet multi-disc clutches and operates much like other transmissions of this type, such as VW/Audi’s DSG/S tronic. One clutch engages the even gears, and the other handles the odds plus reverse. Since only one clutch is engaged at any given time, the transmission anticipates and preselects the next ratio; a gearchange simply requires one clutch to release while the other engages, which means the M DCT can shift quicker than a manual transmission, and it drastically reduces the power interruption between gears. Overall, first gear with M DCT is actually slightly taller than in the manual, but the rest of the ratios are shorter.
The double-clutch arrangement also enables quicker and smoother shifting than in single-clutch automated manuals, such as BMW’s own sequential manual gearbox (SMG) found in the previous M3 and the current M5 and M6. If you’ve ever driven an SMG car, you know what we’re talking about. Even with various iterations and improvements, the current seven-speed unit found in the M5 and M6 leaves large, head-bobbing gaps in power between shifts, rendering it somewhere between annoying and unusable in full-automatic mode.
As with SMG, M DCT has a staggering 11 settings—five in automatic (D mode) and six in manual (S mode)—that determine how aggressive the shifts are, with the most brutal manual setting only available with the stability control off. A setting of four or higher means satisfying throttle blips accompany downshifts; settings one through three yield nearly imperceptible gearchanges. Manual shifting is accomplished via steering-wheel-mounted paddles (right for upshifts, left for downshifts) or the shift lever on the center console.
Thankfully Blessed with Superb Launch Control
In case you ever get your hands on an M3 equipped with M DCT, you need to know how to experience one of the best features: launch control. Omitted from U.S. versions of the M5 and M6, launch control is thankfully now included in the M3.
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