McLaren Sets New Standard With MP4-12C's Transmission

When Italian supercar makers talk about their sequential gearboxes, they usually boast that the shift time is zero, but McLaren says that its new Sequential Shift Gearbox (SSG) for the MP4-12C is lighter and more compact, and while that might not sound as exciting, at least it sounds credible.

According to the official press release, the supplier of the SSG box, Oerlikon Graziano, says it also sets new standards for the refinement and durability of a Dual Clutch Transmission (DCT).

“McLaren has a very clear understanding of its brand and of the type of cars that it should make. This is reflected in the technologies and innovations that are chosen for their powertrains,” explains Oerlikon Graziano head of automotive transmissions Paolo Mantelli. “As well as being immensely fast and dynamically capable, the cars must be comfortable, refined, efficient and a pleasure to drive every day. We worked closely with McLaren Automotive’s engineers to develop a new transmission that would help them meet these targets.”

A DCT unit has become the weapon of choice for any respectable supercar maker as it can combine smoothness and refinement with the possibility to change gear quickly with no torque interruption and therefore no reduction in acceleration.

The diminutive size is driven by McLaren’s need to maximize interior space with no compromise to the car’s dynamics. A three shaft architecture was thus chosen because the parallel secondary shafts help to minimise gearbox length, allowing the engine to be mounted further back. All eight ratios of the transmission use Oerlikon Graziano’s high-performance synchronizes, further optimized to allow substantially faster changes without compromising durability.

“We wanted to achieve genuinely fast, smooth shifting without any of the ‘tricks’ that can be employed to make a DCT feel fast,” says Vocis managing director Mike Everitt, who’s team also calibrated the transmission. “The secret is to get the very best out of the whole control system with a highly-optimized interaction between the software and the hardware. This ensures that the responses are not just quick and accurate but are also consistent and progressive. That means rigorous attention to the fluid dynamics and to the design and calibration of the control algorithms, which are constructed using our proprietary architecture.”