40 mph doubles mileage!

[IsaacCarlson]

I tried driving at 40 mph on the last tank and took off real easy. I was just looking to see what would happen but was blown away by the results.

35+ mpg!!! In a 3/4 ton truck. This is double what I get if I drive normally. No aero mods at all except for folded mirrors. I would love to drive that slow everywhere, but folks get upset when they want to do 60+ and you are doing 40 and there is no passing for at least two miles.

I try to keep it around 45-50 most of the time. Theone thing that really gets me is the gears...1, 2, 3, 4, 5...still on the way to 45....I'm in 5th at 35.

[oil pan 4]

Yeah it works.
Aerodynamic drag starts to make up most of your fuel consumption on a large unaerodynamic vehicle like that above 40mph.
At 40mph a big truck like what we have should require about 6 to 7 hp to over come rolling resistance and closer to 7 hp to over come aerodynamic drag.
Then every time you 2x speed, your horsepower requirement to over come drag goes up by 8x.