This probably is not the best forum to talk about 6.2-liter V8 sports cars going green, but bear with me. The Corvette has been with us since 1953, and none is as fast or fuel efficient as the C7 generation unveiled at the Detroit Auto Show last Sunday. Many details have yet to emerge, but there are three major areas (and several small ones) where the C7 Corvette makes considerable progress in fuel efficiency: direct injection (DI), cylinder deactivation, and 7-speed transmission—most likely in that order.
The new car is not yet EPA-rated, but direct fuel injection will reduce fuel consumption in all driving situations. All things considered, the previous Corvette already achieved “decent” fuel economy of 16/19/26 city/highway/combined. And with a 2,000 PSI fuel injection system, it’s reasonable to expect 10-15 percent increases in fuel economy across the board. DI allows engines to inject very precise amounts of fuel, which allows them to run “leaner,” burning less fuel during each detonation. DI also helps the new engine produce more power and torque (both now at 450), and cleans up emissions since fuel is burned more completely.
The big surprise (to me, at least) was the introduction of cylinder deactivation. Also known as variable displacement or active fuel management (AFM), this technology was first experimented with during World War II and can be found in several other GM vehicles. Over time, this complex method of fuel management has become more common and refined, though it still is not widespread across the marketplace. The Corvette’s AFM system allows it to operate as a 4-cylinder at engine speeds under 3,500 RPM, which will boost highway fuel efficiency by around 10 to 20 percent—likely bumping the Corvette over the 30 MPG mark. In an interview with Car and Driver, Corvette Chief Engineer Jordan Lee said that in 4-cylinder mode, the car is “running on an efficiency range that no other engines can touch,” and that many consumers would be shocked at the Corvette’s highway efficiency.
The final major change that will help fuel economy is the 7-speed manual transmission. GM will be the second company to offer a 7-speed manual (after Porsche), and will probably net an increase of one or two MPGs on the highway. These three changes, combined with low-resistance tires and an aluminum frame, won’t earn the Corvette any awards for green transportation from the Sierra Club. However, it is notable that automakers are pushing for efficiency in historically neglected segments–which is perhaps a symbol of the pervasive and positive effects stricter CAFE requirements are having on the auto industry.
Image © General Motors