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Horsepower= torque {lb_ft} * RPM/5252. Universal hot rodding formula.
The following assumes the same gear ratio:
Torque required is directly proportional to drag force, and therefore, proportional to the square of the speed.
RPM is directly proportional to speed.
Suppose a car requires 35 lb_ft torque to maintain 50 MPH, and is running 1500 RPM.
35*1500/5252=9.996HP
Same car requires (100/50)^2 or 4times the torque (140 lb_ft) to overcome the drag @ 100MPH. It's also running 3000 RPM.
140*3000/5252=79.969HP (8 times what it takes to run 50 MPH).
Maybe someone else can explain it in simpler terms.
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Fuel economy is nice, but sometimes I just gotta put the spurs to my pony! 
Quote:
Originally Posted by thatguitarguy
Just 'cuz you can't do it, don't mean it can't be done...
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Quote:
Originally Posted by elhigh
The presence of traffic is the single most complicating factor of hypermiling. I know what I'm going to do, it's contending with whatever the hell all these other people are going to do that makes things hard.
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