When you receive the BAse map to start e85 tuning, it is best to allow your fuel tank to run down below 1/4 full, and add 4 gallons of e85 and 8 gallons of pump gas (if utilizing the 33% mix) or 2 gallons e85 and 6 gallons of pump gas (if utilizing the 25%mix)
A Cheat cheat is provided below for the 2 common e85 mixes. Please click on the sheet itself for a larger version. Fuel can be added @ any time so long as the ratio added is correct for the map design.
As long as the concentration of e85 is <50%, there should be no additional Maintenance needed as a consequence of running an e85 mix.