Would premium gas compared to regular give you better gas mileage, especially in an ECOboost? A friend tells me he does. I am going to fill mine up today and see if this is true. He said even the 5.0 would as well. It makes sense higher octane more fuel efficient.

 

That's not how it works.

 

I have the 5.0 and I use midgrade...I do get a little better mpg and performance...I would like to try premium but I don't think the added benefit in mpg or performance would be worth the added cost of the fuel.

 

I get better gas mileage with regular 87 than with premium 93 in my 5.0. Seems to perform a little better with the 93.

 

I think you are right. I did a little research on different web sites. There should be no differnece between the two grades. My buddy swears by it. Oh, well. I just finish filling up with premium. I will see.

 

I have 2010 -5.4L when I run premium fuel in it I normally get between .5 to .75mpg better but that possibly is because the higher fuel sometimes does not have the 10% blend of ethanol.

 

1 pack of cigarettes less a week affords me the 89 octane/87 tune combo
Seems to be the best combo I've gotten since messing with different octane/tune/gas stations last 6 tankfuls. 16mpg during the work week. win win

 

Who cares if higher octane fuel gets better mpg when your cost per mile is the same or higher because of the higher price?

You need a mpg increase and the cost difference to be minor to be saving any money.

 

From what I've read is that you have to use what your engine calls (tuned) for in your owners manual.
In all actuality, if your truck calls for 87 and you use 91, you should actually see a drop in MPG. This is because 91 is slower to burn, so you will have an incomplete burn in your combustion cycle, and see a decrease in MPG due to waste. You engine is just not able to take full advantage of the higher octane.

I'm comparing both using non-ethanol gas.

I use 87 and 87 only.

 

My experience - 2010 Fx4 screw

If I run 87 after a week driving back and fourth from work my exhaust will be covered in black carbon. If I run 94 same drive to work, my exhaust tip will be nice and clean. My read out on my dash for mileage will increase slightly, and my truck is more responsive. Smoother at idle.