joecar, as a coder, I believe you should know how having 'magic numbers' in your code is Bad Mojo (TM). Do not use 14.7 unless you can guarantee me that my fuel has a 14.7 stoich. Last weekend I got to play with a car where I spent hours figuring out why my calculations where wrong, and it turned out that the fuel had almost 20% Ethanol in it, throwing off all kinds of calculations.