Originally Posted by Burgundymog
I found my MPG improved with E10

Originally Posted by Taffmog
Mine does too, making it almost cheaper to run on E5.

The calorific value of ethanol (E100) is 29.78 MJ/kg, if you put 10% of the stuff in petrol (E10) the calorific value of the fuel will be decreased from 44.40 to 44.22 MJ/kg, so the difference is tiny.

This is supported by the VTT Technical Research Centre of Finland, they measured fuel consumption under normal driving conditions and their study showed there is practically no difference between commercial petrol grades 95E10 and 98E5.

As I've said already, if you car is E10 compatable, you may as well use E10.