putting a "splash" of e85 in with a tank of 93?

[KrisR]

Well this method obviously isn't for everyone and every car, but under circumstances it can work well IMO. If you "run a lot of boost and are tuned on the edge" like 1wild-horse above said, you have no business running pump gas anyway...that is certainly a recipe for disaster. But, like I said above, if the car is tuned on the rich side anyway on pump premium (10.5-11.0 at WOT, which is a safe level for a fair amount of boost IMO) there's no problem IMO with leaning it out slightly and adding some octane/cooling in the process by mixing in a couple gallons of E85. Again (like I said above) if the car is already on the edge fuel-wise on pump gas (12.0 or above)...which it shouldn't be anyway unless you are asking for trouble, I wouldn't lean it out by adding ethanol to the mix.

Again, not for every car, but it can be used in the right scenario.

 

[ctgreddy]

My thread is based on adjusting the afr's for this mixture. Not sure why everyones saying it'll lean it out and cause the same issue if the tune is slightly corrected for it. Obviously lean is mean and will hurt things, I'm not saying I'm going to tune my car to 11.8 afr and then put e85 in on top of that. I'm saying trying to tune to 11.5 with the e85 and basically only using the e85 for a tad bit more detonation resistance than just pump gas would have.

 

[mustang john]

I thought I remember reading somewhere that when the ethanol content is below 40% the detonation resistance drops very significantly. Maybe something 04Sleeper posted?

 

[03redfirevert.]

On my 03 Harley F150,It would det. a bit accelerating under light loads in d/OD going down the road.Threw 2 gallons of e85 on top of a full tank and it took care of it.No problem with wot fuel trim either.Still do it and have been doing it for 2 years