A Taste of the Next Corvette: G.M. Offers Peek at New V-8

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PONTIAC, Mich.

THE 2014 Chevrolet Corvette -- the seventh generation of General Motors' red, white and blue sports car -- will be unveiled at the Detroit auto show on Jan. 13. To whet the appetites of enthusiasts, Chevy introduced the new car's engine on Thursday.

Called the LT1, in homage to two earlier Chevy engines, the 6.2-liter V-8 is expected to be rated at 450 horsepower, making it the most powerful standard engine ever offered in a Corvette.

The feisty personality of the Detroit-bred sports car stems largely from the small-block V-8 that has served as its primary power plant since 1955. While it's a stretch to say the new engine is a direct descendant of the original Chevy V-8, the power plants do have a common philosophy: minimal mass and maximum power. And they share a basic architecture, a camshaft-in-block configuration.

This type of engine design, once common but now rare, relies on pushrods and rocker arms to open and close valves. Pushrod engines tend to be lighter, lower and somewhat less complex than overhead-cam designs.

General Motors could develop an engine that would conform to current high-performance norms: smaller displacement, overhead camshafts and turbocharged induction. But such a radical change would appall many tradition-minded Corvette enthusiasts. In a media presentation at G.M.'s Powertrain Engineering Center here, Tadge Juechter, the new Corvette's chief engineer, said that when meeting with enthusiasts he would ask how many wanted a twin-turbo V-6 in the new car. No hands were raised.

As before, the Corvette is a front-engine, rear-drive car, and its fans want it to remain that way. Jordan Lee, the program manager for the small-block engine, said a V-8 with overhead cams would have to be four inches taller than the LT1. That means the hood would have to be raised and the car's signature wedge shape would be lost. Relocating the engine to the middle of the car would allow a higher engine and a sleek shape, but to many traditionalists such a design wouldn't be a Corvette.

While the LT1 has a pushrod design that some may call archaic, the rest of its technology is contemporary. The new engine, like the current Corvette's 6.2-liter LS3 V-8, has an aluminum engine block and aluminum heads, but both are new designs.

Direct fuel injection, the most significant refinement, delivers fuel in precise amounts to the combustion chambers rather than to intake ports. That cools the combustion area, enabling higher cylinder pressure, which increases power and efficiency.

With many other engines, high cylinder pressure is achieved with a turbocharger or supercharger. But with the LT1, an 11.5:1 compression ratio -- a tight squeeze of the air-fuel mix -- generates the high pressure.

To further enhance power and efficiency, the engine has variable camshaft timing, which alters the opening and closing of the intake and exhaust valves for better flow control, and G.M.'s active fuel management system, which shuts down four cylinders when the engine is loafing, for better fuel economy. Mr. Juechter said that in moderate driving, the 6.2-liter engine -- large by today's standards -- functions like a 3.1-liter 4-cylinder.

Fuel economy numbers aren't in yet, but gains are expected; the current LS3 engine is rated at 26 m.p.g. on the highway with a manual transmission.

autonews

This article originally appeared in The New York Times.


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