Hi, I own a 2007 Civic Si with k20z3,and Hondata FlashPro Tuner, The 8thgen Civic Si is supposed to run on 91 Octane gas
91+ Octane Gas is super Expensive where im at,
87 Regular is cheap, E85 is cheap

When I mix 66% 87 Regular and 33% E85 the octane goes to about 93octane
I know that full E85 can be harmful to fuel lines and fuelpump, but I heard a mix wouldn't be too bad

My question is, If I keep using a 30% blend E85, will I be good?
Or Do i HAVE to tune for it on FlashPro


I want to avoid a Flexfuel Kit as I dont have enough for it right now,
What are your thoughts?
Thanks!

 

You have to tune for the E85 content. I suggest you spend the extra $5 each fill up.

 

And you would want a flex fuel sensor. E85 is not always 85%. It has a range from 50% to 85% depending on location, weather, season, how much corn they had on hand. Only way to get consistent ethanol content in E85 is to buy racing E85 and that blows the budget right up.


Run 87 and pull timing out of your tunes. No need to monkey with E85. Besides there is more than just octane rating to worry about. Ethanol has far less energy content per gallon than gasoline. You need to burn roughly 30% more of it to make the same power.