BMW N55 inline-six dual scroll turbo

For 2011 the 135i will undergo a motor transplant. It will be powered by the new N55 inline-six. This new 3L motor features a single twin scroll turbo unlike the previous (N54) motor which featured two turbos. The dual scroll is said to provide the same effect as two turbos. The official numbers say just that, at 300hp and 300 lb-ft. all the while giving better throttle response in-part to the inclusion of BMW ‘s famous Valvetronic system on this new 6 cylinder.

The 135i for 2011 will be offered in 6 speed manual or with a 7 speed Dual Clutch transmission (a true auto will not be offered) as we also reported.

The 3 series will also receive this same engine switch with the same 8 6 speed transmissions later this spring. The recently revealed high performance “iS ” version of the 3er will feature a tuned version of the current twin turbo motor (N54) and an optional 7 speed DCT.

BMW N55 inline-six dual scroll turbo

The switch to the N55 is the product of BMW striving to improve fuel economy as part of its Efficient Dynamics initiative, this new motor when coupled with the 8 6speed auto is said to improve fuel economy by nearly 10%. The 8 speed is also said to incorporate auto start/stop to further conserve fuel.

What this also means is that all of you that were looking to tune your next BMW via the aftermarket for those weekend drag races- your window of time is closing as rumors have this N55 possessing some serious anti-hacking devices in addition to the complex Valvetronic system. Personally I rather have a 2011 with launch control and the pending BMW Performance Engine Kit but that is neither here nor there.