Anyone have a rough idea of injector sizing when going from E10 to E85? Right now I'm running normal '91 octane sold in the US which has 10% ethanol on 30# injectors. If I switch to E85, I've heard everything from 30% more fuel needed to only 15% more fuel needed.

Any guidelines?


And I know you are probably thinking "why switch to e85?" Well, a lot of the grand national guys are switching, and are able to run about 10psi more boost on fuel that costs them a little less than the '91 octane they were running before. This is obviously VERY attractive. I have a 10:1 supercharged engine, so more octane would be great.

-- Joe

 

I'd shoot for a 30% increase in injector size, and adjust the ecm for the new constant. It won't hurt to have a little larger injector than necessary, especially with the newer delphi/seimens injectors that have good low pulsewidth performance.