BMW Concept M5 Shifts to Dual Clutch Transmission
As
the high-performance derivative of the previous 5 Series sedan, the 2004 BMW M5
never really captured the imagination of the hard-driving business user in the
way that earlier generations of M5 had done. The high-revving V10 engine,
intended to provide a direct link with the Formula One racers of the time, had a
unique sound and was fiercely potent but the SMG transmission it was attached to
proved unpopular with both magazine road testers and customers.
As a seven-speed AMT with a selection of shift programs, it failed to satisfy the sports-minded drivers yet was also insufficiently refined for gentle driving. The enthusiasts’ response to the AMT was so negative that BMW even went to the extent of later developing a special six-speed manual transmission model for the US market.
At the Shanghai show in April, BMW unveiled the blueprint for its latest hotshot sedan in the shape of the Concept M5. As before, it is closely based on the standard model but has a significantly upgraded mechanical specification, as well as aerodynamic and stylistic changes to the bodywork. Most significantly, the V10 engine is out, replaced by a twin-turbocharged V8, and the AMT transmission makes way for a seven-speed M-DCT. Precise details have yet to be issued, as the model is at present billed as no more than a concept, but it is likely that the transmission is similar to that on the smaller M3 coupé, sourced from Getrag. It is also likely that the M5 will use the M3’s successful transmission control system, where a single switch is able to progressively sharpen the system’s responses, from full comfort to an aggressive sport plus suitable for track use.
In addition, BMW has hinted that the M5’s version of the 4.4 liter V8 engine will be more powerful than those fitted in the X5M and X6M SUVs. Media reports have speculated on 580-plus hp, along with torque outputs in the region of 750 Nm. BMW, for its part, has said that the new engine is 25 percent cleaner and uses one quarter less fuel than its predecessor. Instrumental in this are the broad spread of torque from the twin-turbo engine (in contrast to the very peaky V10) and the addition of a stop-start system and BMW’s Efficient Dynamics package of energy-saving measures.
The driveline is completed by the M-Diff active rear axle with its torque vectoring and traction control functions, to the benefit of yaw stability at all speeds, agility in turns and general responsiveness of handling. The M-Diff also aids performance against the stopwatch. Instead of braking a wheel to prevent wheelspin under maximum acceleration, the differential is able to transfer torque to the wheel with the greater grip – thus boosting rather than reducing the net overall tractive force.
The previous production-model M5 was very accurately previewed by a motor show concept, as was the more recent 6 Series coupé. So there is every reason to believe that this new M5 Concept will appear in BMW showrooms with few, if any, changes this autumn.
| BMW Concept M5 | |
|---|---|
| Engine | V8 Twin Turbo |
| Transmission | 7-speed M-DCT |
| Drive | To rear axle, with active differential and torque vectoring |
| Market Introduction | Autumn 2011 |
Story Filed: 6/07/2011
By Tony Lewin, managing editor DCTfacts.com