2011 Mercedes Benz S63 AMG will receive the company’s all-new 5.5-liter bi-turbo V8 engine, as well as the SpeedShift MCT seven-speed gearbox already on offer in the E63 and SL63. Even though it’s down on displacement compared to the outgoing 6.2-liter engine, the M 157 generates more power (544 horsepower in ’standard’ mode, 571 with the optional performance package) and more torque (586 pound-feet or 660 lb-ft. with the optional performance pack). And despite the change in engine size, the big sedan’s S63 moniker will remain.

The U.S. market will receive start-stop technology despite the fact that its efficiency gains aren’t really recognized by the EPA’s fuel economy testing methodology. Despite offering an embarrassment of performance, the S63 will also cut fuel consumption by an astonishing 25 percent, thanks in part to clever programming of its SpeedShift gearbox and a driver-selectable ‘Controlled Efficiency’ program, an eco-mode that, among other things, instructs the transmission to always start in second gear, shift up as quickly as possible, and remain in higher gears whenever possible. In addition, the Intelligent Generator Management System employed on the E63 is also used to funnel kinetic energy back into the battery, and there is a new generation of cylinder deactivation technology at work as well. All-in, the still-massive motor will turn in an impressive 23.5 miles-per U.S. gallon on the EU cycle and Morninweg pledges that the car will skirt U.S. gas guzzler taxes.

The ’standard’ S63 will run to a governed 155 mile-per-hour top end, while the performance package model has been let out to 186 mph. The new car is slated to go on sale in the second half of the year, and the 5.5-liter engine is expected to supplant the 6.2-liter in other AMG offerings over the next several years. 

The showcar  pays tribute to an early AMG-powered 300 SEL that won its class and finished second overall at the 1971 24-hour race in Spa-Francorchamps.