General Motors has announced a new 10-speed automatic transmission, which it states offers quicker shifts than a dual-clutch type transmission and ‘sets new performance standards’.
The all-new Hydra-Matic 10-speed auto will appear in the 2017 Chevrolet Camaro ZL1, making it the first volume production vehicle to feature a 10-speed transmission.
“There is simply nothing like the experience offered with the new 10-speed automatic in the Camaro ZL1,” said Aaron Link, ZL1 lead development engineer. “It delivers nearly instantaneous, lightning-fast shifts that alter your perception of what an automatic transmission can offer in a high-performance vehicle – whether you’re on the street, drag strip or road course.”
The gearbox uses a wider 7.39 overall gear ratio spread, which Chevrolet states ‘enhances off-the-line performance’, thanks to the use of an aggressive first gear ratio of 4.70. Smaller steps between the gears also help the engine maintain the optimal speed for maximum power at almost all vehicle speeds, especially when on a track.
“The gear ratios are so tightly spaced that the transmission is in the right gear and the engine is at the best rpm for transitions from corners to straights,” said Link. “And with the power from the ZL1’s supercharged LT4 engine, the force you feel in your seat as you accelerate out of a turn will put a grin on your face every time.”
Chevrolet testing has shown the ZL1 with the available 10-speed has faster shift times than the Porsche PDK dual-clutch transmission. In fact, the 1-2 upshift is 36% quicker than the PDK, while the 2-3 and 3-4 upshifts are 27% and 26% quicker, respectively.
“You touch the paddle and the gear changes with immediacy,” said Link. “The shifts happen so quickly and without delay that it almost feels like an extension of your reflexes. It’s a much more involving experience for the driver that really helps improve confidence and performance on the track.”
Chevrolet also states that ‘hundreds of hours’ were spent matching the 10-speed’s shift performance with the unique power band of the ZL1’s supercharged 6.2L LT4 engine, which is estimated at 640hp and 640lb-ft.
The 10-speed also has a numerically lower top gear ratio than Camaro’s eight-speed automatics, which allows the engine to run at a lower speed on the highway, enabling even greater efficiency.
A number of creative packaging solutions have been implemented on the new unit, which despite accommodating an additional clutch and two additional gears in comparison to the eight-speed, allows the new transmission to be the approximate size of the eight-speed transmission.
It uses four simple gearsets and six clutches: two brake clutches and four rotating clutches. That’s only one more clutch than the eight-speed, despite having two more forward gears. It is also the latest transmission with an all-new, proprietary electronic control system and performance calibrations. The calibration is unique for the ZL1’s high-performance-oriented driving experience, while additional applications will feature calibrations matched to their respective performance ranges.
The 10-speed will be produced with an all-new manufacturing system at GM’s propulsion manufacturing facility in Romulus, Mich as part of a US$323m investment in the facility.
Click here for a video of Chevrolet testing the new unit.
May 10, 2016
