I’m new to e85 and have a flex fuel setup / tune. Since summer blend hasn’t come out yet around me I’m curious what everyone has seen as the highest ethanol % out of the pump around them.

 

In Indiana we see as high as 89% from country mark, speedway, and mcclure oil. Lowest i've ever gotten was E75.

 

Wow that’s pretty high! So far (granted its early) I’ve seen 68% in early March and now its coming out at approx 74%.

 

It may just be my general area (northwest-ish indiana). Really though, beyond about E70, most engines don't make more power with higher ethanol percentages. Higher percentages do go bad easier (over time), cause the car to start a bit harder when cold, and result in slightly lower fuel economy. I'd say staying around E60-E70 is best, unless you've seen otherwise!

 

From what Ive read I agree. But since my car has been tuned the fuel multiplier my tuner used for each additional % of E is very rich to stay safe. I’ve gone back once since the E raised 10% to retune and it runs much better. But now that I’ve gone from around 68 up to around 74% its running rich again. My plan with the tuner at this point is to mix the fuel at the pump to keep it around 68 % or lower until the max E% at the pump gets to the highest it does in the summer so it can be finalized at the higher readings to have a true flex fuel tune.

 

83% is technically the max, but you'll occasionally see closer to 90% depending on the economics of it back to the station.

 

May not hurt to get you a big drum of Ignite E90 to finalize your tuning.
We get 92% percent from out here at the pump but my fuel system is more than maxed out at E40.

 

You know what i had that same idea, and figured out where to buy it. So I called my tuner and asked if that would be a good idea and they said no. They told me not to do that because the octane rating in that is higher than what I’ll get out of the pump. They said the e85 to of the pump is blended with cheaper lower octane gas rather than high octane gas like it would be from ignite or VP e85. They told me that the car would take more timing with the ignite e90 than it would with the pump so its not good to tune off of it. Were they just stalling me to come back later?

 

I'm confused. Are you running a flex fuel modification with sensor? The ECM is set to run a flex sensor. Just run a wire from the sensor to the ECM, and turn it on in the tune. Now you can run everything from pure gas to pure ethanol, no retuning required.

Around here, winter blends are about E-66 and the summer blend E-85 is about E-75.

 

Yes i have a flex fuel sensor installed. But hp tuners uses a multiplier in the tune to handle additional timing and fueling per % of E. If the values are off because you didn’t have high and low E values the tune can be off

 

80+ % here in Savannah at the station I use. It could vary I'm sure.

 

No offense, but if anything is off it's probably your custom tune for gasoline. When we tuned my 2015 Z for flex fuel we first tuned it on 91 octane E-10 (the best available here). Then we enabled flex fuel in the ECM, filled her with E-70 and the tuning was done. The multiplier in the ECM for percentage of ethanol does not need changing.

I don't understand what you mean by "you didn't have high and low E values the tune can be off"?

 

That’s a good point I didn’t consider the base tune