The Stovebolt Site Forums The Shop Area Engine Shop Better gas mileage

From Kimberly's lead (and an earlier post)

Let C = Cost of the conversion in dollars
G = Price of gas per gallon in dollars
P = Present Miles Per Gallon
N = New Miles per Gallon
and
M = Miles driven to break even

Then

M=C/[G*(1/P - 1/N)]

For instance if I spend $1000 (C) to boost my mileage from 17MPG(P) to 20MPG(N) and gas is $2.25 per gallon (G)

1000/[2.25*(1/17-1/20)] = 50370 miles to payback

but if I went from a paltry 3MPG to 6MPG (same 3MPG difference)

1000/[2.25*(1/3-1/6)] = 2667 miles to payback