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Old 01-29-2014, 02:09 AM   #19 (permalink)
GeorgeWiseman
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Join Date: Jan 2014
Location: Oroville, WA
Posts: 42

Blue Aveo - '08 Chevrolet Aveo 5
90 day: 25.13 mpg (US)
Thanks: 1
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High Gear ratio...

Quote:
Originally Posted by Old Mechanic View Post
A 63 F series was fairly light. The key to his mileage was the 2 to 1 differential (first post). That's some low revs at 45 MPH.

regards
Mech
YES! Exactly, I think I was only a little above 700 rpm at 45 mph, if I had a tailwind, (on the prairies) I got as high as 36 mpg (average 32 at 45 mph).

The 361 ci engine had the torque to start out OK with those high gear ratios but I could only spin the tires on gravel, not pavement. Once it got up into the higher rpms (highway speeds) went into its true power curve, which is why I could accelerate so fast at highway speeds. I did pretty well against a lot of hot cars, even with the poor aerodynamics, until I needed to corner... It would also catch air as I'd come over the top of hills at 120+ mph... I was young and lucky...

So, for fuel economy with larger engines, gear them up any way you can to make use of the torque and keep the engine rpm low. Larger diameter tires are one way.
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