2015 Corvette Gets 8-Speed Transmission
Truth About Cars
reported last year that the summary of a paper initially published by the Society of Automotive Engineers, since taken down from the SAE site, says that a new eight speed automatic transmission, given the designation 8L90 by General Motors, will be introduced in the 2015 Corvette, on sale next fall. The all-new 7th generation Corvette is currently offered with GM’s 6L80 six speed automatic and a seven speed manual gearbox. The 8L90 is described as being designed for rear-wheel-drive applications and variants will likely be used in GM’s fullsize pickups and in rear wheel drive Cadillacs.
The 8L90 has about the same overall dimensions as the 6L80, and is said to be able to handle up to 737 lb-ft of torque. It has a shorter first gear for better launch acceleration, an overall ratio spread of 7.0 and three speed sensors for better shift response. Other benefits are said to be better fuel economy, improved performance and a quieter car with improved NVH levels.
But remember, Ford and GM co-created the 6L80 six-speed transmission, and was 'reportedly' working on 9 and 10-speed transmissions together.
There was also an early report in 2011 that Ford was working on an 8-speed transmission at the same time(with similar features of the GM transmission), where it now uses the 6R80 in the F-150.
Here is part of the report from PickupTrucks.com
"Ford says it plans to offer new eight-speed automatic transmissions across its vehicle lineup that offer improved fuel economy and ultra-precise shifts.
The gearbox will allow Ford to continue its effort to downsize engine displacement without affecting performance, said Joe Bakaj, Ford's vice president of global powertrain engineering.
"The eight-speed will offer 2 to 6 percent better fuel economy" compared with today's six-speed transmission, like that found in the Ford F-150, Bakaj said. "It will have a wide ratio spread, so customers can run a shorter gear [than today] pulling away from a stop."
The eight-speed will also feature what Ford says is the industry's first torque input sensor. The sensor will measure torque coming into the transmission, enabling faster gear selection, reducing gear hunting and helping smooth out shifts.
"The transmission knows how much torque is needed and will be able to variably control pressure on the clutch packs to deliver smooth shifts," Bakaj said."
So we can expect Ford will be offering an announcement very soon about their new 8-Speed RWD transmission for the newly redesigned 2015 Mustang. Which could be why under Transmission on the 2015 Mustang Technical Specifications
, there is bold Standard
for the 'Six-speed manual with Hill Start Assist'. Which allows room for an Optional 6-speed manual and 8-speed automatic.
But it seems both GM and Ford have something different in mind for their big trucks and SUVs. GM just launched new 2015 pick-ups and SUVs with the old 6-speed. And Ford is launching then 2015 F-150 with the old 6-speed as well.
Now Autoblog has posted the Press Release:
2015 Corvette Stingray to Offer Eight-Speed Automatic
Paddle-shift gearbox rivals dual-clutch performance, enhances efficiency
DETROIT – An eight-speed paddle-shift automatic transmission will be offered in the Chevrolet Corvette Stingray for 2015, enhancing the performance and efficiency of the 2014 North American Car of the Year. Designed and built by GM, the new transmission delivers world-class shift times that rival the best dual-clutch designs.
The all-new, GM-designed 8L90 eight-speed is expected to contribute up to 5-percent greater efficiency
, when compared to the previous six-speed automatic. EPA fuel economy test results are pending and will be announced later. It also makes the Corvette Stingray one of the few sports cars to offer the choice of a conventional manual transmission or an eight-speed automatic.
"Corvette Stingray's new eight-speed automatic delivers the comfort and drivability of a true automatic transmission, as well as lightning-fast shifts
and the manual control that enhance the performance-driving experience," said Bill Goodrich, assistant chief engineer for eight-speed automatic transmissions. "It was designed to enhance the Stingray's driving experience, with performance on par with dual-clutch designs, but without sacrificing refinement."
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.
For performance driving, the transmission offers full manual control via steering wheel paddles. A new transmission-control system and unique algorithms deliver shift performance that 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.
Founded in 1911 in Detroit, Chevrolet is now one of the world's largest car brands, doing business in more than 140 countries and selling more than 4.9 million cars and trucks a year. Chevrolet provides customers with fuel-efficient vehicles that feature spirited performance, expressive design, and high quality. More information on Chevrolet models can be found at www.chevrolet.com