Mercedes-Benz CLS63 AMG

After making its fashion runway debut only three years ago as the world’s first four-door coupe, the highly successful Mercedes-Benz CLS-Class is getting a facelift for the 2009 model year. An instant style icon from day one, the CLS coupe has spurred an automotive industry trend toward more eye-catching four-door cars – vehicles that blur the line between coupe and sedan.
The Mercedes-Benz CLS63 AMG is powered by one of the most powerful naturally aspirated production V8s ever, also the first engine developed entirely by AMG. Built almost completely from a high-strength silicon-aluminum alloy, the 6.3-liter features four valves per cylinder, double overhead camshafts with variable valve timing, bucket tappets (rather than rocker arms), an 11.3-to 1 compression ratio and a variable intake manifold. AMG engineers designed the 6.3-liter engine block with an especially rigid bedplate with cast-in steel reinforcements at the main bearing, and a sturdy closed-deck layout beside the cylinder heads. A first for a production engine, the cylinder bores feature a twin-wire-arc-sprayed (TWAS) coating, a new process that results in impressively low friction and running surfaces that are twice as hard as conventional cast-iron cylinders. Sharing no parts with Mercedes-Benz V8 engines, the 6.3 AMG engine revs freely to over 7,000 rpm, yet already produces nearly 90 percent of its peak torque at only 2,000 rpm