If octane is so important to fuel mileage, then why do we get such dismal mpg on ethanol?
Regular gas = 87 octane
E85 = ~ 95 octane

As far as I am concerned if you want better mileage you want a fuel with more BTU's and not more octane. Octane is more valuable in higher compression engines or conditions that cause fuel to pre detonate.

IMO when you buy premium gas when not needed you are just lining the oil companies pockets.

 

Not according to Ford!

Ford told me that the F150 Ecoboost engine is Optimized for better fuel efficiency on premium fuel. They pretty much told me the 87 octane gas is crap and that I have to run Premium if I want to get better MPG. On one of the other threads I posted the actual Oasis report documenting it. The Service Manager could not believe they said that. Normally you dont get a copy of the Oasis when you have service done.

So to answer your question on what Octane to run for best MPG in an EB F150, according to Ford, it is Premium.

 

So all grades contain equal amounts of ethanol? I thought 87 contained up to 10%, 89 was approx 5%, and 93 was ethanol free.

I usually run 87 ethanol free gas from the mom & pop store up the rode. I've always gotten better mpg than the blended.

 

i have had my truck for 5 years and have only run about 4 tanks of 87, i run 93 all the time every time i ran a tank of 87 it did not run as good as it does on 93 and i get 30 to 35 miles more on a 28 gallon tank, this thing has been beaten to death on every form i have been on you have the guys who say it is not worth you have guys (like me) who say it works just fine, it is each to his own, try it and let us know how it works

 

Very interesting, because that is not what Ford wrote in the owners manual?

 

My mpg on a 3.7L is distinctly better with premium. Last tank with 70% city driving was 19.75 mpg. (Hand measured). Not completely broken in yet, either. I gased up at the last place in town with ethanol free gas, and I think I am doing even a little bit better than that.

Better MPG does not compensate for the cost differential, however. Still, Ford admits that the car benefits from higher octane gas. My attitude is that if it makes that much difference, for as little as I drive, and while the truck is new, I will pay for it.

If you are towing any kind of substantial trailer, I'd say the decision is made for you.

 

Exactly! My Service Manager said the same thing, which is why he gave me the service notes from Oasis. HE couldn't believe they said that!

 

Thanks. 93 it is.

 

I always run 93. The dealer filled it up with 87 and the next tank ran 87. My third switched to 93 and never went back. My throttle response is a little better and mpg went up a little ( about 1 mpg ). I fill at half tank which is a weeks worth of driving 60 miles a day. Only about 3-5 bucks difference for the 93 over the 87. Well worth it in my book.

 

I have a 2011 eb fx4 w/3:73 and just returned from a 1300 mile trip towing 6k and I tested every octane and I got the exact same mileage with 87, 89 and 93 so now I run 87 only unless I am towing in the mountains. btw I get 18-24 around here but towing my 7x16 I only got 10.4 mpg at 60-70 mph on the interstate. At 55 not towing I get 24.3 mpg. Good luck!