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    • GM again claims quicker automatic shift speeds than Porsche's PDK - 2017 Chevrolet Camaro ZL1 10-speed shifts 36% quicker than PDK dual clutch

      Here we go again. GM made similar claims regarding their 8-speed 8L90 automatic. We explored the technical aspects of their claims and basically concluded that the transmission is very quick but no proof was provided of the transmission actually shifting quicker than a Porsche PDK.


      GM this time is providing some concrete numbers but we do not know how they are timing or achieving them:

      Quote Originally Posted by GM
      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-percent quicker than the PDK, while the 2-3 and 3-4 upshifts are 27-percent and 26-percent quicker, respectively.
      Those are big claims but their own text is not proof. It would be great to see the actual testing procedure as well as which PDK Porsche car they tested against.

      Porsche does not even produce their PDK dual clutch gearbox. ZF (ZF Friedrichshafen AG) produces the dual clutch transmissions Porsche uses. GM seems to be using the Porsche name for marketing and to bolster their appearance as being technically on par with Porsche.

      The discussion is pretty much the same as before. As this is a multi-clutch automatic it certainly can 'preload' the next gear much like a dual clutch transmission. This gearbox has six clutches. The 8L90 it replaces had five.

      They made the design more efficient in several ways. The fluid gets up to operating temperature faster. There is a new electrohydraulic valve body assembly that is said to contribute to quicker shift times. There is a new variable displacement vane pump.

      Does that mean this claim by GM is accurate?

      Quote Originally Posted by GM
      New 10-speed auto offers quicker shifts than DCT, sets new performance standards
      Once again, maybe. We would have to see the actual testing procedure. One thing is certain, it will not be a liability in performance compared to a dual clutch. Automatics still have their place in the automotive world.

      GM also went to great lengths to make this transmission compact. That makes one wonder if it will have the same torque capability as the 8L90. This is especially important for those who raise boost on the Camaro ZL1 or intend to add a bigger blower or turbos.


      DETROIT – With faster upshifts than a dual-clutch transmission and a wider overall gear ratio spread to optimize performance and efficiency, the all-new available Hydra-Matic 10-speed automatic transmission sets a new performance standard in the 2017 Camaro ZL1 – and raises the bar for the segment.

      The ZL1 is expected to be the first volume production car to offer a 10-speed automatic. It builds on the established legacy of Hydra-Matic eight-speed transmission family offered on other Gen Six Camaro models, to deliver higher thresholds of capability, refinement and efficiency.

      “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 greater overall performance and efficiency are due primarily to the 10-speed’s wider 7.39 overall gear ratio spread, which enhances off-the-line performance with 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 exiting a corner 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-percent quicker than the PDK, while the 2-3 and 3-4 upshifts are 27-percent and 26-percent 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.”

      Hundreds of hours were spent integrating the 10-speed’s shift performance with the unique power band of the ZL1’s supercharged 6.2L LT4 engine, which is estimated at 640 horsepower and 640 lb-ft of torque.

      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.

      Creative packaging
      Creative packaging solutions, which had to accommodate another clutch in comparison to the eight-speed, allow the 10-speed to be the approximate size of Camaro’s other 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.

      Additional highlights:

      • A reduction in spin losses, thanks to only two non-applied clutches and other design features, contributes to greater fuel efficiency
      • New ultra-low viscosity transmission fluid reduces friction across the full temperature operating range for greater fuel efficiency
      • An internal thermal bypass allows the transmission to warm up faster to its optimal operating temperature for additional fuel efficiency
      • Advanced torque converter design contributes to packaging efficiency.


      The 10-speed will be produced with an all-new manufacturing system at GM’s propulsion manufacturing facility in Romulus, Mich. It’s part of a $323-million investment in the facility, which employs 850 hourly and salaried workers.

      GM Hydra-Matic 10-speed vs. eight-speed gear ratios
      Type: 10-speed automatic eight-speed automatic
      Gear ratios (:1)
      First: 4.70 4.56
      Second: 2.99 2.97
      Third: 2.15 2.08
      Fourth: 1.80 1.69
      Fifth: 1.52 1.27
      Sixth: 1.28 1.00
      Seventh: 1.00 0.85
      Eighth: 0.85 0.65
      Ninth: 0.69 --
      Tenth: 0.64 --
      Reverse: 4.87 3.82


      This article was originally published in forum thread: GM again claims quicker automatic shift speeds than Porsche's PDK - 2017 Chevrolet Camaro ZL1 10-speed shifts 36% quicker than PDK dual clutch started by Sticky View original post
      Comments 7 Comments
      1. BlackJetE90OC's Avatar
        BlackJetE90OC -
        A lot of the 8-speed criticism came from the lag from the paddle pull to the actual gear change. To the point were it was quicker just to drive it in auto mode. The actual 8-speed measured gear change was quicker.

        In this video the 10-speed looks immediate and GM rectified the lag from the paddle pull to the actual gear change. They might have something here by fixing the paddle lag and the mechanical gear change being even quicker than the 8-speed.

      1. Sticky's Avatar
        Sticky -
        Click here to enlarge Originally Posted by BlackJetE90OC Click here to enlarge
        A lot of the 8-speed criticism came from the lag from the paddle pull to the actual gear change. To the point were it was quicker just to drive it in auto mode. The actual 8-speed measured gear change was quicker.
        Same with the M3 DCT at least E9X. Hated the input lag so I would just throw it in auto when I needed perfect redline shifts.
      1. Zeee_Q's Avatar
        Zeee_Q -
        It might shift as fast as DCT or PDK from 1st to 2nd gear and so on, when it only needs to go to the next gear, but let's say you're cruising on the freeway and decide to floor the gas, I doubt it will be capable of doing the same instantaneous drop to 3rd gear PDK is capable of doing as fast as a PDK.
      1. Sticky's Avatar
        Sticky -
        Click here to enlarge Originally Posted by Zeee_Q Click here to enlarge
        It might shift as fast as DCT or PDK from 1st to 2nd gear and so on, when it only needs to go to the next gear, but let's say you're cruising on the freeway and decide to floor the gas, I doubt it will be capable of doing the same instantaneous drop to 3rd gear PDK is capable of doing as fast as a PDK.
        Maybe and it probably lags on the downshift aspect as well.
      1. 93siro's Avatar
        93siro -
        Hate on SMG all you want but that trans has the best paddle action time in any transmission i have ever driven.
      1. BlackJetE90OC's Avatar
        BlackJetE90OC -
        Click here to enlarge Originally Posted by 93siro Click here to enlarge
        Hate on SMG all you want but that trans has the best paddle action time in any transmission i have ever driven.
        Yeah SMG gets a lot of hate. But I still miss my E46 M3 SMG from back in the day. I like how it was raw and each gear shift snapped your neck.
      1. Sticky's Avatar
        Sticky -
        Click here to enlarge Originally Posted by 93siro Click here to enlarge
        Hate on SMG all you want but that trans has the best paddle action time in any transmission i have ever driven.
        Exactly what I was going to say. It was like I was connected to the transmission. When I click upshift at redline that is exactly what it did.

        The DCT gets all this praise yet its input lag sucks. No major magazine or reviewer ever mentioned the superiority of the SMG in this respect they just bagged on how terrible it was.

        I never had any problems with it.