acdii

If you are going up grades, you do want to use Premium. Made the mistake of using 85 in Colorado once, once. There is no 87 there. Use 91 instead. In non mountain climbing though 87 has worked out just fine.

mikeinatlanta

On my 5.0 premium is good for a couple mpg and very noticeable difference. Times have changed and old rules no longer apply.

smokeywren

Back when my 2012 3.5L EcoBoost was new, I did extensive testing of regular vs, premium when towing my 5k TT and 6k cargo trailer - mostly across the plains where regular was 87 octane and premium was 91.

Results?

Premium increased MPG enough to pay for the higher cost of premium. Plus the F-150 seemed to "like" towing with the premium a lot more than struggling with regular. So no downside to using premium when towing.

But I was required to plan way ahead and have a nearly-empty 36-gallon gas tank before filling up with premium for a towing trip.

Ideal prep would be to haul a 5-gallon can of premium, then run out of gas before you pour in that 5 gallons of premium, then drive to a gas station and fill up with premium.

I haven't towed with the 2019 yet, so no comment on whether it needs premium or is more cost effective using premium. But Ford still says to use premium when towing, so I probably will, even if it's not cost effective.

mikeinatlanta

The newer direct injected and dual injected motors are an even bigger difference than your 2012. Unlike older motors that were either ping or no ping, the new motors can make significant adjustment to take advantage of the increased octane.

chimmike

yeah, knock retard systems are quite a bit more advanced. My 07 Mazdaspeed was the same way. It'd sense KR, but couldn't adjust timing enough to compensate....and you'd get a datalog with a lot of KR on it and outright panic.

RubyRed Canadian

2016 F150 3.5L Ecoboost towing out 8200lbs trailer, I couldn't notice any difference between 87 or 93, so I stuck with 87. I tow at 65MPH in 5th gear (lock out 6th). The truck runs smoooooooth.

untraceable

Ecoboosts are some of the only turbo motors capable of 87. That doesn’t mean they like it. One of this big tuners showed a stock G2 eco hitting knock detectors on 87. So much more when it’s hot out, run premium when towing

acdii

Thats the Fact Jack! The 85 was by mistake since I was running regular the entire trip. Going up that first 6% on I-70 in Colorado, the truck ran really hot. That truck only had a 26 gallon tank so the next fill was not too far away and I used Premium after that, truck pulled much better and ran somewhat cooler too. Lesson learned, check the Octane before filling, not the label.

I have yet to run premium in my 18 yet, but the 14 and 16 saw no difference in MPG when towing, and since the 16 ran like crap regardless of a tune or not with premium I just ran 87 all the time. The 14 with a 91 tow/perf tune ran great and got better MPG in the summer on Premium.

Maury82

I run premium when towing, especially during the heat of the summer day, and I can tell the difference in how it pulls..

On a cool summer night, I may consider running regular if the terrain is flat enough.

schmenke

Almost identical situation for me..
Pulling our relatively lightweight TT (~5,000lbs) on an identical route on separate occasions to one of our favourite campgrounds, using both 87 and 93 octane, I definitely noticed a difference in performance.
Nowadays I only use the premium juice when towing, and find the benefits most noticeable in the mountainous areas in my neck of the woods.