The MY 2015 Chevrolet Corvette Stingray will offer a new 8-speed automatic transmission designed and built by GM. GM expects the new 8L90 eight-speed to contribute up to 5% greater efficiency, when compared to the previous six-speed automatic. EPA fuel economy test results are pending and will be announced later.
The new option makes the Corvette Stingray one of the few sports cars to offer the choice of a conventional manual transmission or an eight-speed automatic.
The available 8L90 transmission is based on the same eight-speed automatic that will be offered on the supercharged 2015 Corvette Z06, but with unique clutch and torque converter specifications matched to the torque capacity of the Stingray’s LT1 6.2L naturally aspirated engine.
|New 8L90 8-speed. Click to enlarge.|
For performance driving, the transmission offers full manual control via steering wheel paddles. A new transmission-control system and algorithms deliver shift performance that GM says rivals the dual-clutch/semi-automatic transmissions found in many supercars but with the smoothness and refinement that comes with a conventional automatic fitted with a torque converter.
The transmission controller analyzes and executes commands 160 times per second. Wide-open throttle upshifts are executed up to eight-hundredths of a second quicker than those of the dual-clutch transmission offered in the Porsche 911.
Smaller steps between gears, compared to the previous six-speed automatic, keep the engine within the sweet spot of the rpm band, making the most of its horsepower and torque to optimize performance and efficiency.
With four gearsets and five clutches, creative packaging enables the new eight-speed automatic to fit the same space as the previous six-speed automatic. Extensive use of aluminum and magnesium make it more than eight pounds, or 4 kg, lighter than the six-speed. Design features that reduce friction contribute to the expected 5-percent greater efficiency.
The 8L90 is built at GM’s Toledo, Ohio, transmission facility.