Exclusive: BMW Goes From SMG to DCT

The Sequential Manual Gearbox (SMG) was the predecessor to the recently released DCT for performance oriented BMW models.

There were original plans to introduce the SMG in the E90 3 series sedan after 10/2005 as an option that required the then N52 330i engine and the Sport Package (ZSP). All of the training materials and press releases at the time stated the SMG would eventually be offered. BMW even completed a product comparison between it and the VW/Audi DSG of the time. This all changed weeks before these cars were to be built, BMW had made the decision to forego the SMG in non-//M cars until further notice. There were many unhappy soon-to-be SMG owners.

There was little explanation as to why, but many in the know talked of BMW having access to their own 7 speed dual clutch setup and that being the possible reason. Other reasons included the US customers not warming to the SMG and the countless warranty claims filed. As we have previously stated the //M5/6 engine was designed to be used solely with the SMG; though modification were made and the manual transmission was offered specifically at the request of the US market.

In 2005, ZF had reached the end stages of development of a 7 speed dual-clutch transmission. The official announcement came mid-September; the same time BMW pulled the plug on the SMG in the 3 series. This raised suspicion that BMW would offer this instead of the SMG. When this did not happen it was assumed it would at least make its way into the newly designed coupe, and it was close.

While testing was going on for the DCT, ZF had also created a new transmission that had increased efficiency, had ultra fast shift times but in comparison to the DCT it would be 6 speeds and significantly cheaper to produce initially. This was because it relied on a modified torque converter and additional modified components found in existing slush-box automatics. This transmission has since gone on to be acclaimed as one of the best true autos in the world and can be found throughout the BMW lineup in such cars as the 335i. The DCT was obviously held back by BMW.

When designing the newest //M3 BMW had no choice but to go to a V8 engine that revved sky high in order to out do the competition. This is where the original Audi DSG (S-tronic) designed by Borg-Warner could not compete, it could not handle the high revs or torque a modern performance engine would throw at it (Although recently Audi has previewed a new performance version). So instead of using the SMG in the //M3 BMW decided to use the DCT, which can handle up to 500 ft/lbs. and 9000 RPMs without issue. This not only gave BMW a V8 engine for the //M3 but a transmission that would outclass the competition. We would not be surprised to see the added to the other //M cars as well this fall.

So for two plus years BMW tested the transmission and designed the software programs marketed as Drivelogic until it was recently released. The BMW gearbox has 11 Drivelogic control (shift) programs, five in automatic (Drive) and six in manual (Sport) that tailors the transmission to specific driving styles. The driver can shift for himself by putting the lever into S mode and then shifting along in sequence. The paddle shifters on the steering wheel (right for upshifts, left for downshifts) are similar to the former SMG. It’s worth noting that many of these programs are meant for //M cars only.

With the LCI (Life Cycle Impulse) of the E90 already in the works and rumored to be scheduled for release this coming fall the possibility of the DCT making its way into the car should finally occur. It will be a stripped down version in comparison to the //M. Drivelogic will not be as necessary and more than likely will not be a part of the system or at most it will feature a couple of shift pattern options.

This transmission in conjunction with the N54 engine will be a good pairing. If you add in the idea that the e-diff from the 1-Series (as reported previously on BF, this will also be added to the E90 lineup) this makes for an excellent performance car and something even the new to market A4 will have trouble competing with.