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The gears are close enough that it has decent acceleration and good fuel economy without "hunting" all the time. What's the point of having 9 speeds if the 8th and 9th gears constantly shift in and out with every little hill? That would be annoying to me.
The point is that with more speeds there is less "hunting" involved.
My 8 speed is extremely smooth and potent, you barely feel the transition and it surely saves gas.
The point is that with more speeds there is less "hunting" involved.
My 8 speed is extremely smooth and potent, you barely feel the transition and it surely saves gas.
It's still doing a lot of shifting, whether you feel it or not. More shifting = more wear.
Location: East of Seattle since 1992, 615' Elevation, Zone 8b - originally from SF Bay Area
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Quote:
Originally Posted by Retriever
Perhaps I can interest the OP in a state-of-the-art Chevy from the '60s with a 2-speed Powerglide transmission...
I learned to drive in a 1964 Chevelle, with the 283 V8 and Powerglide, and it got 18 mpg, 22 on trips.
The additional gears now are needed to balance off the additional weight of safety equipment, and the smog equipment required by law, to meet the MPG requirements.
It's still doing a lot of shifting, whether you feel it or not. More shifting = more wear.
More shifting probably means more wear. But that also means the engine spends more time in its "good" RPM range, assuming the programming of the transmission is good. That uses less fuel, may accelerate quicker, and might even reduce engine wear if it spends less time at higher RPMs.
Most automatic transmissions are made by ZF. GM designs transmissions for themselves and for other marques including Chrysler.
10 speed is supposed to be to this year and they are working on 12 speed.
At some point they are merely getting miniscule gains in efficiency which matters to no one except the government (and therefore to the manufacturers). They become more interested in vechicle performance numbers on paper than in real world conditions. For this reason a manufacturer will spend millions designing a seat that is 3 pounds lighter, then the purchaser will carry a gallon of water in the boot for emergencies and all the benefit of those millions redesigning the sea are lost. However the manufacturer does not care what happens in the real world. They care only about meeting government requirements on paper.
Thus adding more gears and improving efficiency by 1/10th of a mile per gallon is significant to the government and therefore to the manufacturer. Then they can say the program is working and there are forcing the manufacturers to make more and more efficient vehicles. The consumer care not one whit about the 1/10th of a mile per gallon more. They do care about the added cost for that 10 speed transmission though.
More shifting probably means more wear. But that also means the engine spends more time in its "good" RPM range, assuming the programming of the transmission is good. That uses less fuel, may accelerate quicker, and might even reduce engine wear if it spends less time at higher RPMs.
This is why I said I thought 6 speeds was just right for most cars, good performance and fuel economy with the least amount of excessive shifting. At 65mph my 4cyl Sonata runs at only 1850 rpm, that's pretty low for a four banger. I don't think a 10 speed could do much better.
I think we're there already with 9 speed transmissions. And there are already a lot of issues with those
The problems with the 9-speed ZF transmission all stemmed from Chrysler's adaptation to make it work with the Cherokee. That's why it operates just fine in the 200, Range Rover Evoque, and Acura TLX.
Quote:
Originally Posted by BrendanSWM
Most automatic transmissions are made by ZF. GM designs transmissions for themselves and for other marques including Chrysler.
Even Chrysler is primarily using ZF units now. ZF is definitely one of the biggest headliners, but you also have Hyundai, Toyota's Aisin, Nissan's JATCO, Honda does some in-house work, Getrag, and Mercedes-Benz. And of course GM as you mentioned.
Personally I think tbey shouldv'e stopped at five, the only auros that need more than that are the ones in busses, and Rigs. If you want fuel economy, I think your only options should be a cvt, or a manual.
Personally I think tbey shouldv'e stopped at five, the only auros that need more than that are the ones in busses, and Rigs. If you want fuel economy, I think your only options should be a cvt, or a manual.
What is the engineering basis for your opinion? Manual transmissions are now outperformed by automatics - Ferrari doesn't even offer a manual now. Many compact cars have better fuel economy with an auto than a manual.
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