Quote:
Originally Posted by jcp123
I myself have kinda wondered about this. 5- and 6-speed autos seem right for the task at hand - more than that and it does seem like there's a bit of busywork along with a lot of marketing. I am told that these designs are not really more heavy or complex but I do wonder on that count.
The 6-speed on my wife's Chrysler (I really need to update my info here, lol) seems to border on busy but works pretty well considering it's a nearly 4800lb vehicle with a 3.6l engine tugging it along, and according to the FCD it's been getting mid-high 17s on my wife's in-town drives, along with 30+ on the freeway.
I had good access to a smorgasbord of cars in the 2011 period and I was generally happy with the 6-speeds I had. CVTs seemed a bit more picky - smallish Nissans did well but the Quest felt as busy as anything around. The 5-speed auto in my Dad's Passat felt similarly competent.
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Added gear counts=more weight/complexity
This is a simple indisputable fact. For a 7 speed to be the same weight as a 6 speed, the 7 speed must be built of less robust parts.
Also, someone mentioned earlier that all that stuff is always spinning, meaning that the parasitic losses of a tranny would increase as you increase the number of bits inside that are spinning.