[aerohead]

Originally Posted by AeroMcAeroFace

Delta- 10% Cd = delta - 2% EPA Combined mpg Re: SAE Paper 740969

Delta 10% Cd = delta- 8.82% mpg, Re: Robert Stempel, Manager, Chevrolet Motor Division, General Motors Corporation, Re: GM, Chevrolet Citation-IV concept car, 1984.

So what you are saying is that a 10% reduction in drag will give you anywhere between 2% and 8.82% MPG increase? To me that doesn't seem particularly useful.

"I got 2% increased MPG therefore I have 10% reduced drag" "I then did more mods and increased my MPG to 8% above baseline" therefore I can conclude that the further mods made no difference to aerodynamic drag because they both correspond to 10% drag reduction.

Please re-read for specificity. All caveats and conditions are clearly indicated.