What fuel do you use?

[2018ExpyPlatinum]

So, the take away is obvious. If your car doesn't need premium (per the book) why would you use it? If the good book says 91 or 93 must be used, you suffer without it. If you can use 87, but 91 is recommended, do what you want.

But again, other than octane, gas is gas. It's all the same, brand doesn't matter.

 

[Fastcar]

I've been reading for years about the benefits of higher than called for gas. So just for the hell of it I figured I'd do a mileage test on our 2021 Expy 4X4 King Ranch with HD towing 3:73 gearing with 23K miles on it. This truck has given 19.1MPG combined city highway driving since we broke it in using 87. I figured 3 tankfuls using 93 would be telling. A combination of my wife (who does the majority of city) and myself driving and a mix of 60/40 city/ highway miles would tell us something. Soooo..after spending a dollar plus more a gal. for 93 gas our mileage jumped to 19.5MPG. Did it run better? Nope. Was there an increase in performance? Not in the SOP dyno. Was I happy? No, I was out some money for a marginal return.
This isn't the old days when you could crank in some timing or change heat range on the plugs or play with jets. These things are are putor controlled trucks with the areo of a damn brick. It is what it is. A big heavy truck. Enjoy it for what it is. If you want economy buy a compact.

 

[sdinwiddie85]

Does it say in the manual that 91+ is needed for the SPP? I haven't looked.

Not required, you can run 87. Full power rating is 91+.

 

[BravoAlpha]

In regards to TOP TIER - Some Costco are, some not. Same for Wal-Mart/Sam’s Club

I was curious if there was something to it. 5000 miles on 87, 5000 on 91-93
inconclusive.

 

[mdecillis]

Not required, you can run 87. Full power rating is 91+.

So it is required to get the extra power. Does anyone know what the power rating is if you don't use 91+?

 

[2018ExpyPlatinum]

@mdecillis ...As I remember, non 91+ use gives you the standard 375 hp/470 tq.

EDIT:

From the brochure:

"EcoBoost® power delivers up to 400 horsepower *5 and 480 lb.-ft. of torque *5

*5--Horsepower and torque ratings achieved with 93-octane fuel"

OMG....93 octane!! So it's tuned to use 93. You can't even get 93 out west. Guess I'm going back to 87 and say F it.

 

[blkZ28spt]

Gas is gas...but additives in that gas do vary. Top Tier gas is proven to keep top end parts/back of valves cleaner. And often Top Tier is less expensive than other, so, why not seek it out? Costco, QT, etc.

93 Octane because every Ecoboost owner manual recommends 91+ for best vehicle and engine performance. And I want the best performance. Boosted engines have to pull timing and reduce output and run hotter to run on 87. Which they will. But, they run better on higher octane

 

[Dahammer]

Since ownership, at the end of May 23, I use premium. Come winter, regular.

 

[2018ExpyPlatinum]

Gas is gas...but additives in that gas do vary. Top Tier gas is proven to keep top end parts/back of valves cleaner. And often Top Tier is less expensive than other, so, why not seek it out? Costco, QT, etc.

To continue this dead horse, if you're buying your gas from the usual suspects (QT, Circle K, Costco, major travel centers, etc), it IS top tier. Technically, even Joe on the corner is top tier. The only issue with Joe on the corner is how OLD is his gas. Again, it's all pulled out of the same pipeline, tank, trailer. Those "additives" only amount to about 1%, so about an ounce in a gallon. You probably have more "moisture" in that Top Tier gas than "additives". And do you really know if you're getting those additives? Companies pull gas first by price (what supplier is cheapest) then by allocation. I've seen many a load being pulled as "generic" going to name brand stations (think Shell or Sunoco without those advertised "additives") based on price or allocation. And your Costco gas is as generic as it gets. I know too much about the business....I've already told you too much.

 

[Wangle]

Top Tier, always. 87 Ethanol usually. I get almost exactly 10% better mileage with 91 ethanol free. Always Premium when towing.