AMG GT to be first recipient of new 4.0-liter twin-turbo V8.
Mercedes has officially confirmed the upcoming Mercedes-AMG GT will be powered by this: the carmaker's brand-new 4.0-liter twin-turbo V8 developing 503 hp and 479 lb-ft of torque. Known internally as M178, the 90-degree quad-cam direct-injection unit was built from the ground up and replaces AMG's naturally-aspirated 6.2-liter V8 (M159) that will be phased out along with the SLS AMG.
The engine features a range of cutting-edge powertrain technologies including flow-optimized cylinder heads, forged internals, nanoslide coating for the cylinder walls and dry sump lubrication.
A pair of Borg Warner turbos sit between the 90-degree angled cylinder banks, while M178 also has the same 83- and 92-mm bore and stroke measurements as the 2.0-liter turbo unit powering AMG's compact range. With 126.3 hp per liter, the M178 in the new GT develops 35.6 hp per liter more than the M159 in the SLS AMG. But with a swept volume of 3982 cc – 2226 cc less than its predecessor – its 503 hp has 65 hp less than the engine it replaces. The new AMG engine's 479 lb-ft of torque equals that of the M159 unit, however. After the Mercedes-AMG GT arrives in the fall, the engine will feature in the C63 AMG that should break cover by year's end.