Following an announcement for Europe, BMW has confirmed that the output for the U.S.-spec V-8–powered iterations of the 2013 5- and 6-series will increase by 45 hp and 30 lb-ft of torque. Specifically, the 2013 550i, 550i GT, and 650i coupe and convertible will inherit the same higher-output version of the brand’s twin-turbocharged V-8 as the latest 7-series and new 6-series Gran Coupe.
The extra power comes from the addition of Valvetronic—BMW’s variable valve timing and lift system—to the twin-turbo 4.4-liter V-8. BMW’s move to install the more powerful N63Tü engine in the 6-series coupe and convertible, as well as the 5-series and 5-series GT (yes, that misshapen coupe still roams the streets freely), is hardly a surprise. When BMW launched the 2013 6-series Gran Coupe, we speculated that its meatier V-8 could spread to BMW’s other models that offer eight-cylinder power. It makes sense for BMW to have all of its V-8–powered offerings propelled by the same powerplant, but strangely the eight-cylinder versions of the X5 and X6 will keep the lower-output iteration of the 4.4-liter engine..