2010 BMW 5 Series Gran Turismo Technology

BMW's 5 Series Gran Turismo is the second vehicle off the new architecture that underpins the 7 Series and will form the basis for next year's 5 Series sedan and wagon and the next-generation 6 Series. Here are some of the highlight technologies:

3.0-LITER, DIRECT-INJECTION TURBO SIX
The new 5 Series Gran Turismo marks the first application of BMW's new single turbo, direct-injection, 3.0-liter straight six with Valvetronic variable valve timing. The engine has 3.53-inch bore and a 3.31-inch stroke and a 10.2:1 compression ratio. It develops 300 horsepower at 5800 to 6250 rpm, and 300 pound-feet of torque between 1200 and 6000 rpm. The decision to go to a single, twin-scroll turbocharger was driven by the need to meet forthcoming Euro6 and American SULEV emissions while retaining the responsiveness of a twin-turbo setup. The single-turbo layout allows closer placement of the catalytic converter for faster light-off. (The tough new Euro6 test means the catalytic converter has to be hot enough to be scrubbing exhaust emissions just seven seconds after the engine is started; BMW also utilizes a dual-wall exhaust manifold for maximum heat retention.) The twin-scroll layout funnels the exhaust gases from cylinders one through three and four through six to two separate turbines, ensuring an exhaust pulse hits each every 120 degrees of crankshaft rotation, as in a twin turbo setup, minimizing pulse interference and maximizing the energy transfer.

EIGHT-SPEED AUTOMATIC TRANSMISSION
First seen on the just launched V-12 powered 760i, BMW claims this new transmission's unique layout provides two additional ratios with no increase in bulk or weight. Four planetary gearsets and five clutch packs are controlled in a way that no more than two of the clutch packs are freewheeling at any given time.

Faster shifts are a further benefit because only one clutch pack is disengaged, and downshifting more than two gears is accomplished as a direct shift. For example, a downshift from eighth to second is made with only one clutch pack disengagement, and therefore occurs without stepping down through the intermediate gears. That means the 5GT can maximize time in eighth gear with the engine turning minimal revs - the 535i GT's 3.0-liter six is turning at just 1600 rpm at 60 mph - but still deliver fast kickdown response.