Speed Freaks - American Car - Specifications

Renntech Mercedes-Benz Clk60A Porsche-Eating Luxo-CoupeFiddling with the superb Mercedes-Benz CLK is like approaching a piece of fine art with a touch-up brush; it would be far easier to ruin than improve. RENNTech founder and former AMG technical director in North America, Harmut Feyhl has the credentials to pull off an envelope-expanding transformation worthy of the automotive elite and celebrities that are his customer base.

Beginning with a perfectly desirable Mercedes-Benz CLK430, RENNTech yanks the 4.3-liter/275-horsepower SOHC V-8 to punch it out to a 6.0-liter displacement by increasing both bore and stroke. Only premium components-purchased from AMG suppliers and custom-milled by independent shops-are used in the exhaustive $50K engine conversion. "My cars are going to still be expensive even if I can save a few hundred dollars here or there," says Hartmut, "To me, it is worth it. I know these components are the best money can buy."

RENNTech-spec upgrades include lightweight Mahle pistons, aggressive camshafts, valves, connecting rods, rocker arms, intake manifold, throttle body, mass air meter, external oil-to-water cooler, engine management programming, and carbon-fiber air filter housing. Resulting output is 408 peak horsepower and nearly 500 pound-feet of torque

In a corollary $19K procedure, the standard five-speed automatic transmission was ambitiously replaced in this car with a Getrag six-speed manual. Even though Mercedes told Hartmut the swap was impossible, a few won't-take-no-for-an-answer insiders assisted in the development. The manual transmission works with a heavy-duty Sachs dual-mass flywheel and clutch, a setup designed to withstand the 6.0-liter's brutal power onslaught.