Quote:
Originally Posted by bandit86
My o6 corolla gets 55-65 mpg cruising at 55 mph At 65 mph it's down to 32-40 At 75 I get high 20s. Love my scangauge.
Why I want to test is constant speed in different gears, to see why the drastic change. Is it engine efficiency that suffers, aerodynamics or rolling resistance. I will cruise and check differen speeds in different gears, what I wish I had was a 10-15% larger tire I could put on to lower engine speed a highway speed
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Probably Air Resistance...drag increases with velocity squared.
Power to overcome air resistance increases with velocity cubed.
Note that the power needed to push an object through a fluid increases as the cube of the velocity. A car cruising on a highway at 50 mph (80 km/h) may require only 10 horsepower (7.5 kW) to overcome air drag, but that same car at 100 mph (160 km/h) requires 80 hp (60 kW).
en.wikipedia.org/wiki/Drag_(physics)