For the first time in its 38-year history of souping up Mercedes-Benzes, AMG has developed a new V-8 of its own, sharing no major parts with other Mercedes engines. Even the cylinder-bore spacing is different.
Following in BMW's footsteps, this mill does without turbo- or supercharging, generating its grunt instead from big inches and high revs. Most of the tech that permits this is old hat: light, strong, direct-acting bucket-tappet valvetrain; big bore and short stroke; variable cam phasing and intake-manifold tuning; etc.
Innovations include placing two gigantic throttle bodies in the valley (shortening the distance to the intake valves for optimum performance) and a novel, low-friction cylinder-lining technology. Instead of casting or pressing iron liners into the aluminum block, extremely high voltage is applied across two iron rods creating an arc of plasma in the presence of a proprietary gas. This plasma causes the iron to atomize, depositing a 0.3mm layer of iron on the cylinder wall. Applying the iron this way gives it a unique crystal structure that, when machined to a thickness of just 0.1 mm exposes a network of micropores that retain an oil film, greatly reducing friction.
The results are impressive--503 horses and 465 pound-feet--though they fall just short of the Corvette Z06's naturally aspirated pushrod V-8 by two horses and five pound-feet. Oh, and just as Chevy rounds the Z06's 427.6 cubic inches down to "427" for historical expediency, AMG is liberally rounding 6208 cc up to "6.3 liters" to conjure fond memories of Mercedes's first musclecar, the 1968-1972 300SEL 6.3 (which actually displaced 6332 cc). Look for the new engine to make its debut in the M63 AMG SUV in 2006.