Horatiu B. wrote:The new BMW 5 Series GT continues to receives a well deserved attention from the automotive journalists. As expected with any new model, the 5 GT technology and design are being “dissected” and all the fine details are being exposed.
While ourrecent coverage on the 5 Series GT focused mostly on the design language, both interior and exterior, the fellows at MotorTrend decided to take a deeper look at the technology powering the 5 Gran Turismo.
“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.”
Full Article Continued
Author: Horatiu B.
Source: http://www.bmwblog.com/2009/09/25/motor ... n-turismo/