2011 Mercedes-Benz S63 AMG

Mercedes-Benz’s AMG performance division unveiled its new twin-turbo, direct-injection V-8 engine today in the S63 AMG Showcar, at its headquarters in rural Affalterbach, in the hills outside Stuttgart.

The new V-8, code-named M157, is based on the existing 5.5-liter V-8 (M273) that’s widely available throughout the Mercedes lineup. It will make its debut this fall in the S63 AMG and in the all-new, next-generation CL coupe, presumably as the CL63 AMG. Yes, that’s right: the badging will remain S63 even though the displacement will be 5.5 liters. But, really, what does that matter? Even the current AMG V-8, the M156, is actually a 6.2-liter, not a 6.3-liter, so Mercedes is just continuing its illogical badging because it wants to evoke the glories of the historic 6.3 badge.

Friedrich Eichler, head of powertrain development for AMG, explains that the new twin-turbo engine is actually rather conventional in design. “We use one turbo per cylinder bank and [rely on] very, very good volumetric efficiency [to prevent turbo lag] We also made the turbo diameter as small as possible.”

Eichler elaborates on the many changes made to the base V-8 for this new AMG application: “We changed the crankcase and a lot of geometric parts. Structural stiffness is improved, especially in the area where the crankshaft is rotating, where we made the ventilation holes smaller, for more rigidity. We have also made huge efforts toward mechanical efficiency, to reduce friction. We have roller finger followers and we have changed the pistons, the connecting rods, the diameter of the crankshaft, and the bearings. We also have a better cooling system.”