GM: Vette Z06 to get high power, high mpg

DETROIT -- The supercharged 2015 Chevrolet Corvette Z06 that goes on sale early next year will produce 650 hp, the highest ever for a General Motors production car.

But the engine is only half the powertrain story. Larry Nitz, GM's chief engineer for transmissions, says the Z06's new eight-speed paddle-shift automatic transmission will shift faster and smoother than the dual-clutch automatic in the Porsche 911 Turbo S.

Nitz, speaking to reporters recently, said the superfast shifts were accomplished with fast electronic solenoids and other controls.

The new gearbox replaces a six-speed automatic and weighs about eight pounds less because of extensive use of aluminum and magnesium.

Chevrolet officials have said they expect the Z06 to be one of the most fuel efficient cars of its type. The outgoing 2013 Z06 was rated at 24 mpg highway.

The new powertrain will be exclusive to the Corvette, which starts at $53,995, including shipping. Chevrolet has not announced prices for the 2015 Z06 yet, but the final 2013 Z06 had a starting price of $76,595, including shipping, according to Edmunds.

GM engineers targeted the Porsche 911 Turbo S as they were developing the Z06's LT4 engine and the eight-speed transmission. Chevy says the Z06 has 90 more hp and 134 more pounds-feet of torque than the 911.

The Corvette also should maintain its weight advantage over the Porsche. The 2013 Z06 weighed 3,175 pounds while the 911 Turbo S weighs 3,538. The weight of the 2015 Z06 has not been released, but the car uses a new, lightweight aluminum frame.

Nitz would not say if the Z06's 8L90 transmission will replace the eight-speed automatic from supplier Aisin AW Co. that GM uses in certain performance versions of the Cadillac CTS. But if GM follows its usual practice, the 8L90 will debut in the Corvette and migrate to other performance vehicles, such as the Chevrolet Camaro Z/28 and Cadillac's V-series vehicles.

GM is working with Ford Motor Co. on a new generation of nine- and 10-speed automatics, the first of which debut late next year. Ford is engineering the 10-speed, which will be used in rear-wheel-drive vehicles, while GM is developing the nine-speed for front- and all-wheel-drive vehicles.