New 9-speed General Motors transmission boosts fuel economy 2%
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Some automakers love CVT's (looking at you, Nissan); others (and most auto journalists) don't. Adding more gears to conventional slushboxes seems to be the way the CVT-haters are headed. Tasty bits, from the Detroit Free Press: Quote:
I've never driven a 9-speed, but have personally heard people complain about the shift quality of the Fiat/Chrysler ones: shift quality and seeming never to get into top gear. |
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Let us know what you think.
One complaint from a fuel economy angle was the top gear would only engage under the lightest possible throttle. Which means almost never for most drivers? |
2% How do you accurately measure that? Im going to guess that will be completely lost in real world driving.
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On the dyno, running the EPA test cycles is my guess.
More gears ain't bad if they increase the spread, which they've done in this case. (Lower cruising RPM.) What bugs me is when they add more gears, but the top ratio is basically unchanged... though maybe that's more of a manual gearbox phenomenon. |
Personally I prefer 1-2-3-4-5-INFINITY!
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Quote:
Simon |
I suppose more gears makes sense if one is engineering for the EPA test, or hilly or urban/suburban stop-n-go stoplight Gran Prix.
As a small-town flat lander, I still like the notion of a three-speed stick, direct drive top "gear" and tall enough final drive to negate the need for overdrive. Because as a percentage of time, accelerating = minute while steady-state highway cruise = vast majority and I don't want any energy being wasted on spinning a bunch of gear sets that aren't doing anything. |
^ Do any of the vehicles in your fleet match that description?
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I've driven an 8-speed, over-sized pickup truck a couple of times. Basically, with my light foot, the engine never changed RPMs after coming up from idle/giving it a bit of gas. It just let the torque converter accelerate the truck, then switched gears before letting the engine spin up any faster. Up and up through the gears at all of 2k rpm, even out on the highway.
Of course, it had plenty enough torque behind it to do that. |
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