With the arrival of the 2011 CL-class, Mercedes-Benz has the opportunity to show off its latest advancements in powertrain, luxury, and safety, all wrapped in a two-door package. The big news for Mercedes' freshened coupe is under the hood of the CL550 4Matic, with the introduction of a new 4.6-liter V-8 producing 429 horsepower and 516 pound-feet of torque, coupled to a seven-speed automatic transmission.
The 4.6-liter engine is more powerful and more efficient than the 5.5-liter V-8 it replaces, and joins the CL600's esteemed, though aging, 5.5-liter V-12 that produces 510 horsepower and 612 pound-feet of torque. Mercedes claims the new twin-turbo, direct injection V-8 delivers 10 to 15 percent better fuel economy than the outgoing 382-horsepower 5.5-liter V-8, which, for now, will continue to power its stablemates across the Mercedes line. All CL550s will continue to come standard with 4Matic all-wheel drive mated to a seven-speed automatic transmission, since there is no fuel economy penalty for the 4Matic's extra weight of roughly 150 pounds.
An AMG-tuned CL63 evokes Mercedes' storied 6.3-liter V-8 that helped launch AMG as a brand, but in name only. A more efficient 5.5-liter V-8 displaces the outgoing 6.2 (which was also badged as a "6.3" on the car), producing 536 horsepower and 590 pound-feet of torque over the wide range of 2100-4600 rpm. The M157 twin-turbo engine is mated to a wet-clutch, seven-speed automatic like the one offered in the SL63 AMG, and avoids the costly gas guzzler tax. In AMG tradition, the hand-crafted engine is still signed by the individual who built it. As for the monstrous CL65, its twin-turbo 6.0-liter V-12 will now produce 621 horsepower and 738 pound-feet of torque and still sends its power to the rear wheels through a five-speed automatic transmission.