Road Test: 2005 Chevrolet Corvette C6 Roadster Revealed
A rich houseguest's charms make this the best top-down Vette ever
Something happened at the swinging Bowling Green bachelor pad of America's favorite sports car, the Corvette. A snooty rich aunt from Cadillac crashed and made herself comfy. But this visitor turned out to be more Auntie Mame than Auntie Em, and her high-class fun-loving ways rubbed off on our hero, who suddenly seems an all-new man. And the transformation is most evident when he's dressed in the top-down couture favored by his rich Auntie XLR. Don't get us wrong, as roadsters go--even $50,000 ones--the pre-XLR C5 Corvette was a stout piece of work, thanks to many patented structural design elements like bumper-to-bumper hydroformed frame rails (still the largest in the industry), a structural backbone tunnel, and a floorpan made of balsa wood and composite sandwich material. But when Madame XLR blew into town dressed to impress, she shared her fitness secrets with her new housemate. Both are better off because of the relationship.

Stiffer, more compact bumper beams are more rigidly attached to the frame rails of the new car, and with shorter front and rear overhangs, they contribute more to chassis stiffness, especially near the suspension mounts. A new hydroformed lower-instrument-panel brace anchors the door pillars to the center console to help eliminate the dreaded cowl shake. And a thick aluminum panel replaces the steel sheet that's bolted to the bottom of the C5's central backbone tunnel.

The aluminum door-pillar and windshield surround structure is redesigned to use more extrusions and fewer castings for improved dimensional accuracy and rigidity. In fact, this structure is so rigid that the C6 roadster passes federal roof-crush standards (which convertibles are not even required to meet) without the use of any pop-up or freestanding hoops or rollbars. Finally, a fiberglass tub forms the trunk and bonds the bodywork to the frame rails while segregating the trunk compartment from the passenger space to reduce body shake and dramatically reduce road noise. This also secures the trunk when the top is down and the doors locked--the C5's trunk compartment is always open to the cockpit.
The design team launched a crusade to reduce cockpit noise that was just as vigorous as its effort to bolster structural rigidity. They added a startling 15 pounds of acoustic-damping material to further squelch tire, suspension, and road noise--amazing in a car for which light weight is valued as much as or more than high horsepower. (Don't worry, the engine lost 15 pounds to offset it, and indeed the base C6 roadster is expected to have dropped 50 pounds.) The new soft-top, available in black, gray, or beige, has been tailored and aerodynamically optimized to reduce wind noise. Its profile is rounder, its crossbows don't protrude as prominently, and the five-ply Twillfast fabric and rubber-membrane top is thicker to damp noise transmission. The side-window glass now powers down and up slightly when the door is opened and closed for a better seal, and extensive aero tuning has lowered the drag coefficient fractionally (from the C5 roadster's 0.31).


