Quote:
Originally Posted by Old Tele man
...+1,000 on that!
...it's basically a constant-power curve situation, ie: the product of two numbers, MPH and MPG:
CONSTANT = MPH * MPG
...you "trade" one for the other, against the basically 'constant' product of their two values...hence, the slower you go, the better the MPG (up to the point of lugging the engine); and, conversely, the faster you go, the worse the MPG.
...it's a nice smooth curve, from vertically assymptoic MPG down to horizontally assymptoic MPH. Look at those Corvette FE curves that were posted here awhile back!
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There is one other important variable in that equation: Gearing.
I used to drive a Corvette, '94 LT1 with a 6spd. Very low Cd and very high gearing in the tranny (0.50:1 OD). It had a very torquey V8, but there is a limit to how low you can get your revs. I usually drove at around 60-65mph, because if I slowed it down to 55mph I had to downshift to 5th and would get worse mileage than at 60+mph. I could get 29mpg in straight hwy driving with that car.
Mike