The 2013 BMW 5 Series GT offers more horsepower but is even more fuel-efficient than the prior model year. BMW’s improvements were first seen on the 2013 BMW 5 Series GT in UK but the U.S. models for 2013 will also get them. The 5 Series GT is powered by the automatic engine stop-start and the same selectable Eco Pro driving mode that’s used on the 2012 BMW 3 Series sedan.
Under this mode, fuel economy is maximized due to the tuning of throttle inputs as well as other energy-saving settings. This is exactly the reason for the improvement in the mpg ratings of all 5 Series GT models. BMW asserts that the 535i GT will improve by 2.25 mpg and the 550i GT will get a 4.6 mpg boost.
The 535i GT is powered by the same 300 hp and 300 lb-ft of torque but the 550i GT’s power is higher by at least 10%. Powered by a 4.4-liter twin-turbocharged V-8, the 2013 550i GT could experience a boost of 45hp and 30 lb-ft to 445 hp and 480 lb-ft.
It seems that BMW accomplished this by switching engines. BMW’s N63 engine was used on the 2010-2012 550i GTs while the N63Tu powerplant is used on the 2013 and onward models as well as the 2013 650i Gran Coupe. It’s likely that the recently modified V-8 will be used on the new 5 Series sedan but so far, there has been no confirmation.