Mercedes-Benz is rolling out a biturbo replacement for the thundering naturally aspired 6.3-liter V-8 being used in most AMG performance models. The new 5.5-liter engine employs direct injection with spray-guided combustion, piezo-electric injectors, adjustable camshafts and twin turbochargers. The standard 5.5-liter V-8 biturbo engine develops a peak output of 536 hp and maximum torque of 590 lb.ft. In conjunction with the AMG Performance package, these figures increase to 563 hp and 664 lb.ft.
The new engine achieves more than a 25 percent increase in fuel economy to an estimated 22.4 mpg, along with better performance. The fuel economy is also in large measure due to the standard start/stop function. This system is active in the transmission’s Controlled Efficiency (“C”) mode, and switches the eight-cylinder engine off when the car comes to a stop. In “C” mode the sports sedan always starts in second gear, and the transmission shifts to the next, higher gears at a noticeably early stage. With its high torque at low engine speeds, the V8 engine encourages a smooth, effortless driving style.
The engine will first be used in the S63 AMG, which accelerates from 0 to 60 mph in 4.4 seconds, with a top speed electronically limited to 155 mph. The performance version makes the run in 4.3 seconds and has a top speed limited to 186 mph.