2004 Chevrolet Impala SS

For the past four decades, Chevrolet has periodically used the "SS" (Super Sport) suffix to designate special high-performance models. The heritage of the Impala nameplate stretches back even further to the top-of-the-line 1958 model that set the stage for performance-oriented luxury passenger cars. An Impala SS option group followed in 1961, taking Chevrolet into the opening days of the musclecar era. Soon, the Impala SS became a distinct model, avidly sought by high-performance fans who liked the idea of vigorous V-8 power in a full-size automobile.

Painted in monochromatic black, 2004 Impala SS boasts bright stainless steel dual exhaust tips and special "SS" badging.

In 1994, after a long absence from the line, Chevrolet brought back the Impala SS badge on a high-performance sedan. An offshoot of the mid-1990s rear-drive Caprice, the SS was painted in black and powered by a potent V-8, with suspension improvements to match. That model lasted only through 1996. When the Impala name was revived for the 2000 model year on a new front-wheel-drive sedan, no SS edition came along for the ride.


That lack has been rectified dramatically for 2004. Not only is the SS designation revived as one of three Impala trim levels offered this year, but the new sedan is powered by a supercharged V-6 engine. A similarly supercharged V-6 goes into the top SS version of Chevrolet's Monte Carlo coupe.


Supercharging is a mechanical system, built to concentrate the air that enters the engine's intake manifold. This yields a more powerful combustion stroke, which increases both horsepower and torque output. Driven by a belt, the SS's Eaton supercharger is said to deliver "smooth, linear power with virtually no lag" after the gas pedal is pushed to the floor. Turbochargers, in contrast, are operated by exhaust gases.

Inside, the Impala SS driver faces a racing-inspired six-gauge instrument cluster that includes a supercharger boost gauge.

Cranking out 240 horsepower and a burly 280 pound-feet of torque, the supercharged V-6 works with a heavy-duty variant of the electronically controlled, four-speed automatic transmission that is used in other Impala models. A direct-mounting air-conditioning compressor has been installed, to reduce vibration. Inside the engine, powder-metal connecting rods substitute for conventional cast-iron rods, which reduces weight and increases durability.