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Old 04-05-2020, 08:02 PM   #19 (permalink)
Hersbird
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Join Date: Feb 2014
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Quote:
Originally Posted by MeteorGray View Post
I have always figured that after achieving high gear in any car, the lowest RPM value will yield the highest fuel economy.
I used to think that as well but with direct injection, a turbos, and an 8 to 10 speed transmissions I'm not so sure about that anymore. They are building in lower, and lower highway cruise RPMs all the time looking for better economy at 65 mph. With the turbo and direct injection they can get a good BSFC over a big range, but with 2 or more overdrive ratios the spped can get pretty high before you reach "top gear". Then maybe one of the lower gears would have less aero drag while still being at peak efficiency.
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