Originally Posted by hp jnkey
Do you get more bang for the buck if you run 5 gallons E85 with a fill instead of 3 gallons?
You are only using the Ethanol to clean up timing corrections & run aggressive tunes, and a bit more ponies. it you are not properly tuned you really are not getting any power benefit per say, from 5 gallons.
Ethanol is less dense, thus it takes more fuel than regular pump gas. I haven't done any comparison, but, I am getting about 15 mpg with 50% Ethanol vs my 18 mpg I was getting with ACN 91. As my DD
And of course the E50 Tune is for performance not for MPGs.
if you wanted to do the math, 8.5 gallons of E85 and 7.5 Gallons of 91 is my current setup.
about $3.60 gallon E85
about $4.40 gallon ACN 91.