Mercedes-Benz is launching a new generation of direct-injection, twin-turbocharged V-8 engines with more power and better fuel economy beginning with the freshened 2011 CL coupe that goes on sale next month.
The CL550 has a 4.6-liter V-8 that replaces a 5.5-liter V-8. The new powerplant will be used in the S-class sedan and E-class family in the 2012 model-year.
The second new engine is a 5.5-liter V-8 built by Mercedes-Benz' high-performance AMG division. That engine replaces the normally aspirated 6.3-liter V-8 and will be used not only in the CL63 AMG but also in other AMG vehicles. It has direct fuel injection and a start-stop feature that turns the engine off when the vehicle stops and restarts it when the gas pedal is pressed.
The 4.6-liter, 429-hp engine is 20 percent smaller than the powerplant it replaces. The direct-injection bi-turbo engine uses two turbochargers and has 12 percent more horsepower than the outgoing engine but is 10 percent more fuel-efficient.
The new 5.5-liter engine has 536 hp, an improvement of 3 percent, and is 20 to 30 percent more fuel-efficient.
Final EPA fuel economy numbers for the vehicles with the new engines are not yet available.
Mercedes-Benz will keep using the current generation V-12s in the CL600 and the CL65 AMG.