This tune update is for existing FA20 (2015-2021 WRX) customers who want to get an E60 map for their setup.Blending for E60 is both safe and effective on these cars. To blend for E60 you'll mix 2 gallons of premium fuel (can be 91oct or 93oct) and the rest will be E85.It is recomended to have an upgraded fuel pump for E60. To blend for for E60, we recommend a ratio of 2-3 gallons of of premium fuel and the rest E85. If your fuel source is at at E60-70, 2 gallons of gas is best and if your fuel source is 75-85% then 3 gallons if best. You can use 2.5 gallons to be safe if you aren't sure. Maintain this ratio when topping off meaning if you are filling up from a half tank, blend in 1 gallon of gas and then top off with E85. We do have a good amount of adjustment in the tune to handle variance in the blend so don't worry about this more than just following the suggestion above. You can also install an Innovate or similar ethanol gauge to monitor the blend in your tank if you wish. Blending for E60 works the same for 91oct or 93oct fuel so no need to worry about that as long as you are using premium fuel to blend with. If at any point you feel you may have blended to far in the wrong direction, don't worry, just drive the car easy until you can add more gas or E85 to correct things close to E60.
