Mercedes-Benz's upcoming 4.7-liter twin-turbo V8 will offer a 22% improvement in fuel economy while the 3.5-liter V6 offers a 24% improvement. These engine enhancements, which are comparable to gas-electric hybrid jumps, result to the delivery of more power too. It should be noted that these are Mercedes' estimates and that official EPA figures have yet to be provided.
In addition, a huge part of that fuel economy originates from Mercedes' newly standard start/stop system. This means that there won't appear to be as huge a fuel economy improvement on US-market window stickers since the EPA's current testing standard doesn't actually indicate the improved real-world economy that stems from this type of system.
The new V8 is a direct-injected twin-turbo unit of 4,663 cc displacement. Mercedes said that this engine, which will be used in the CL-Class coupe and S-Class sedan this fall, will deliver 435hp and 516 pound-feet of torque, up 12% and 32% respectively.
Due to this direct injection system, Mercedes will be able to run the engine at 10.5:1 compression ratio. The V6, which has a new architecture, goes from a 90 degree V angle to 60 degrees. Furthermore, it has all-new intake and exhaust and will deliver 306 hp and 273 lb-ft of torque.
Mercedes-Benz asserted that an S350 (a model not offered in the US) will lead to a 24% better fuel economy than the old S350. Notably, the improvement is largely due to the standard stop/start system.
The company has yet to announce what model the new V6 will debut. Both new engines get additional ancillary units (the water pump, oil pump and fuel pump) that use up less of the engine's power. Both motors are also equipped with intelligent generator management systems.