Originally Posted by serialk11r
I can understand why 7 might be too much for a manual transmission, but how is it bad that an automatic has more gears?
A lot of you are mentioning "torque band", but that's totally missing the point. What we actually care about is efficiency band, not torque band, and more gears helps put you there faster. If a shift drops you from 2500 to 1600, the engine is quite a bit less efficient than if the transmission could keep the revs above 2000, during acceleration.
If you're going >50mph, then you're probably in the tallest gear, but what about 45? Or 35? Or 40? If at 40mph you have to shift into 5th gear in a 6 speed, that could mean running the engine 60% faster with wide spacing, and losing 20% fuel economy. An 8 speed avoids that by having 2 gears closer together in that range.
More speeds also lets you bring 1st gear lower, reducing torque converter losses, or in the case of a DCT, less heat at the clutch.
I'm also not convinced there isn't a workaround for 7 speed M/Ts. Aston Martin's new V12 Vantage S M/T has a dogleg pattern with 1st gear under reverse, to the left. I imagine 1st and reverse would be blocked once you get rolling, and then you use 2-7 in the usual H pattern. That sounds workable to me. Porsche blocks 7th gear if you are in 4th or lower, which is probably not as good since if you're in 7th and trying to downshift, finding the right gear is going to be way harder.
Finally, all that said, I'm kind of surprised to see 9 and 10 speed automatics showing up on the market. I mean, maybe on a 7L Lamborghini, which can hit the rev limit in 7th gear, but 8 seems like it would be more than enough for most cars...I suppose 9 speeds gives you a lower 0-60 time for bragging rights, since most cars space 1st and 2nd further apart.
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