The Porsche Taycan's Two-Speed Gearbox
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Re: The Porsche Taycan's Two-Speed Gearbox
#2I'm surprised ZF/Porsche didn't turn this into an eCVT, as an eCVT (a la Prius) has probably the same complexity, but with the added benefit of having more ratios. I suspect it would also reduce shock loads on the transmission as a result of shifting.
I wish the article would have gone into this, because I suspect Porsche said no more for marketing reasons rather than technical ones, as CVTs are universally hated in car performance circles.
Re: The Porsche Taycan's Two-Speed Gearbox
#3I'm surprised ZF/Porsche didn't turn this into an eCVT, as an eCVT (a la Prius) has probably the same complexity, but with the added benefit of having more ratios. I suspect it would also reduce shock loads on the transmission as a result of shifting. I wish the article would have gone into this, because I suspect Porsche said no more for marketing reasons rather than technical ones, as CVTs are universally hated in…
Wouldn't an eCVT require an additional motor?
Re: The Porsche Taycan's Two-Speed Gearbox
#4FWIW the original Tesla roadster was also a 2 speed, but they dropped the gearing as soon as they could meet their original top-speed without it.
Re: The Porsche Taycan's Two-Speed Gearbox
#5It's a little surprising that even with a two-speed Gearbox the Taycan has neither better range nor low range 0-60 acceleration than the Tesla P100D (which has the same size battery). Obviously spec comparisons aren't the whole story and the handling and high-range acceleration may be better on the Taycan. Looking forward to seeing more comparisons and already glad to see more EV models in this category.
Edited incorrect comment about top speed.
Re: The Porsche Taycan's Two-Speed Gearbox
#6Seems logical. I think most manufacturers have just decided that they'd rather use an over-sized motor than deal with a transmission, but if you're willing to tolerate a more complicated drive-train you get more usable power with less weight.
Using a transmission might get weird if you have multiple motors, though. For instance, it would be odd to have the front wheels in one gear and the rear wheels in a different gear, or the right rear wheel in a different gear than the left rear wheel.
Re: The Porsche Taycan's Two-Speed Gearbox
#7It's a little surprising that even with a two-speed Gearbox the Taycan has neither better range nor low range 0-60 acceleration than the Tesla P100D (which has the same size battery). Obviously spec comparisons aren't the whole story and the handling and high-range acceleration may be better on the Taycan. Looking forward to seeing more comparisons and already glad to see more EV models in this category. Edited incor…
According to the article:
> It’s programmed to shift between its two speeds at 43 mph, though the computer can be programmed to make the change at different points based on the route, topography, or the distance the driver hopes to cover before plugging in.
I wonder if that shift point has anything to do with the slower acceleration. I'd imagine it would make a small difference.
As for the top speed, I believe Tesla is limited to 155mph and the Taycan is reported to be limited at 161mph. So the Taycan is actually faster, but I'm not sure how much it matters since both are limited by the software.
Re: The Porsche Taycan's Two-Speed Gearbox
#8As I understand it, this gearbox type is key on Porche's intent to make it able to maintain performance over use rather than overheat, notably it improves acceleration and efficiency at high speed. I would expect the Taycan to use less energy to maintain 150mph.
Re: The Porsche Taycan's Two-Speed Gearbox
#9Seems logical. I think most manufacturers have just decided that they'd rather use an over-sized motor than deal with a transmission, but if you're willing to tolerate a more complicated drive-train you get more usable power with less weight. Using a transmission might get weird if you have multiple motors, though. For instance, it would be odd to have the front wheels in one gear and the rear wheels in a different g…
From what I've read, the AWD versions of the Model 3 (possibly others) actually do this (different ratios in the front and back). As the article says, Tesla had a hard time building a transmission that wouldn't tear itself apart under the torque of the electric motors.
So, they put the front and back motors at different ratios. The back motor is used at lower speeds, and the front motor kicks in at higher speeds.
Re: The Porsche Taycan's Two-Speed Gearbox
#10I'm surprised ZF/Porsche didn't turn this into an eCVT, as an eCVT (a la Prius) has probably the same complexity, but with the added benefit of having more ratios. I suspect it would also reduce shock loads on the transmission as a result of shifting. I wish the article would have gone into this, because I suspect Porsche said no more for marketing reasons rather than technical ones, as CVTs are universally hated in…
A CVT can't handle as much torque as a gear-based transmission.