Quote:

BTU's Per gallon:

Regualr Gasoline = 114,100
Ethanol (E85) = 81,800
Propane = 91,600





1. Note: BTU value of gases is based on density at one atmosphere at 60 degrees Fahrenheit.

2. Sources:
a. North American Combustion Handbook, 3rd Edition
b. Automotive Fuels Handbook, SAE

Work in the propane industry myself in design/sales of propane cargo tanks and pumping systems. I have some experience with LP as an alternative fuel in Medium Duty chassis but very limited.

So these are just facts that I thought might be beneficial to the post. Obviously as stated by others there are many more factors other than btu's to be considered.