MUNICH, Germany -- BMW AG will replace its 3.0-liter gasoline engine with what it claims is the world's lightest six-cylinder engine.
BMW engineers have designed a magnesium-alloy composite crank- case that reduces the assembled engine weight by about 22 pounds to 354 pounds.
The engine's performance is increased by 12 percent while fuel consumption will drop by 12 percent, BMW says. Klaus Borgmann, BMW's head of powertrain engineering, says further development of the automaker's 3-year-old Valvetronic engine management system provided most of the reduction in fuel consumption.
The new Valvetronic units deliver 258 hp - 12 percent higher than the 3.0-liter gasoline-powered units.
Other fuel-saving features include a water pump using just one-tenth of normal power, letting the engine reach optimum temperature more quickly from a cold start.
The inline six-cylinder engine will debut in the new 630Ci coupe and convertible. It will replace gasoline-powered 3.0-liter engines in the 7 and 5 series, X3, X5 and Z4.
But BMW will not offer the engine in the 3 series until the next generation is launched.
Rival Mercedes-Benz abandoned inline six-cylinder engines in 1999 in favor of V-6 configurations. An inline unit is smoother, with less noise, vibration and harshness, but is more difficult to install and more expensive to produce.