OVTune: ethanol-free vs premium?

Hi all. Sorry if there’s an answer to this but I have not been able to find it by searching the forums.

I just ordered my VFtuner kit and wanted to know if there’s consensus on running the regular tune with ethanol-free gas vs the premium tune with 91 blend? No 91 clear where I live (ethanol-free is 88 Octane so I don’t think I’d want to try ethanol-free with the premium tune). I’ll be able to try both but I’m eager to hear what others have experienced.

I’m in Utah, so relatively high elevation FWIW.

 

How easily available are gasoline stations near you that have ethanol-free high octane gasoline all the time?

 

It's not 100% of gas stations but it seems to be pretty high nowadays. I'm more likely to encounter one than not. And for about 95% of my driving I will be fueling up at a specific station I know has it.

Those in Utah are familiar with Maverik gas stations (they're all over) and it seems like there's been a big push to add ethanol-free 88 to each one (at least at a few pumps).

 

Premium tune, ethanol free premium. other than the first tank from the dealer, my truck has only ever saw eth free fuel. Ski

 

This would be my preference, but unfortunately I don't see ethanol-free premium very often.

 

https://www.pure-gas.org/index.jsp?stateprov=UT

appears lots of stations on Utah, have it. Ski

 

From that link it looks like there's quite a lot of 88 clear but not nearly as much 91 clear.

 

I am curious how the truck would run when tuned for the regular tune for ethanol-free if filled with ethanol added fuel?

 

I too am curious what to tune for using 89 or 90 octane Ethanol Free gas. Would mapping to the 87 Ethanol gas mapping be okay to use, and live with (sometimes between fill-ups I can't get the ethanol free, such as on trips out of state), or do I have to go up to the Premium blend mapping configuration for it all to "play well"?

 

Ethanol will obviously make more power at the expense of mileage. There is a 'reason' why all the WRX STi guys tune for E85 if available ;-) Probably not much difference between say, E10 and premium but the octane rating of ethanol is so high that with the right parts and tune, big power can be made. I think Ford lists two different HP specs for the Coyote 5.0...one with gasoline and a higher hp figure when running ethanol.

 

Ethanol is less energy dense than gasoline and will result in poor fuel mileage. On the order of 20% worse or so, depending on the compression of the engine and how well the ECU can take advantage of it. If you put e85 in a vehicle that is not tuned for it, it will make poor power and get terrible mileage.

Boosted engines can benefit big time from e85 because it's effective octane rating is very high, like 100 or something, so high boost and more timing advance can be used to overcome the energy density losses that come with e85. It also has a higher vapor pressure than gasoline so it cools the air charge more than gasoline, which further helps forced induction engines.

I'd be interested to see the coyote 5.0 info about e85 making more power than gasoline. I've never heard of a NA engine having high enough compression to be able to make more power on e85 and not have problems with gasoline.

Edit: just read an article from hotrod about e85 in the newest generation coyote 5.0. pretty cool that it makes more power with no hardware changes, only requires a tune. +20hp (530 vs 511) isn't all that much percentage wise and I'm assuming it kills mileage.

 

Oh yeah it does! E85 can wack 20-30 percent off... But remember, guys building a 500+ rwhp WRX STi or 1,000 hp Mustangs don't worry about mileage ;-)

 

88 E0 and a bottle of Lucas octane boost?

 

Putting e85 in the 2GR isn't going to help, tune or not, unless it's blown.

 

All the stations in my area are ethanol free, so I have OVTune on 91 octane (Shell VPower)