BMW to abandon high-revving engines in M cars; X6 first 'M' to get turbo

[LeMansX5]

Tough emissions standards worldwide and soaring manufacturing costs in Germany are behind BMW's decision to switch from high-revving, naturally aspirated engines in its M high-performance vehicles to turbocharged direct-injection powerplants, beginning as early as next year.

The move, which could alter the character of BMW M models, places question marks over the immediate future of the M3's 4.0-liter V8 and the M5's 5.0-liter V10. Both engines will make way for forced-induction engines in coming years, according to high-ranking BMW sources.

The first M vehicle to make the move to the new turbo powerplants is the X6 xDrive M, which will challenge the Porsche Cayenne GTS and the Mercedes-Benz ML63 AMG.

Set to appear next June, the X6 xDrive M will be the first model to run BMW M's new twin-turbocharged V8. This engine is also earmarked for the next-generation M5, due out in late 2010.

Based on the standard X6 xDrive 5.0i's 4.4-liter 90-degree V8, the new twin-turbo unit is said to match the current M5's naturally aspirated 5.0-liter V10 for power at 500 hp, while providing as much as 516 lb-ft of torque.

This should be enough to provide the M-powered X6 with 0-to-60 mph acceleration of less than 5 seconds and top speed limited to 155 mph.

"In terms of overall performance, the new engine doesn't give anything away to the powerplant we run now, but it delivers much better consumption and lower emissions," a senior BMW M official told AutoWeek.

The move comes as Mercedes-Benz's AMG performance unit is planning to turbocharge its 6.2-liter V8 when it introduces direct injection in 2010.

Besides developing new turbocharged engines, BMW's M division is also planning to equip new models with features such as automatic stop/start and brake regeneration in a bid to cut fuel consumption and emissions.

BMW is also testing a new driveline incorporating technology from next year's X6 ActiveHybrid, with a nickel-metal-hydride battery pack used to power an electric motor to boost performance levels.