RobZ71LM7

Some have obviously not read the manual because otherwise they would be surprised. Ford recommends premium for towing and high loads. Regurgitating stuff you've heard on the internet isn't helpful.

BlackBoost

Funny because MY owner's manual for my 2015 2.7 EB doesn't say that anywhere, it says:



So 87 it is, as recommended in my owner's manual on page 169, like I've been doing for the last flawless 77k.

johndeerefarmer

Ford recommends higher octane for towing and/or high temps. If you don't want max power available then don't use it.
I tow year round and use premium year round. I am also running a 91 per/tow tune from 5 star so I also run it for that reason.
Ford says you get about 10 hp and 15 lb feet of torque if you run premium. As a guy who tows heavy I want all I can get.

RobZ71LM7

Funny because MY owner's manual for my 2017 3.5 EB says exactly what I posted. READ the SUBJECT of the thread: 2017 3.5 Ecoboost. What's next owner's manual excerpts from a 2007 5.4 3V? Or telling the OP how a Chevy runs on 93 octane.

iknfixit

Only have 12k mi on 10 speed screw. 17-3.5 gen 2. I've gotten 24 mpg running around 60 near Raleigh NC. On I-40 in a 400 mi round trip. Running from there to Birmingham Al on I-85, I-20 etc average just over 20 mpg running 75. All 87. Put 242k mi on my old 2011 3.5 and only ran 87... no knock, no ping. Tow 6700 lb camper. I just put 91 in occasionally to make it feel like it ran faster lol.

BigDozer66

My 2017 owners manual states:

"For best overall vehicle and engine
performance, premium fuel with an octane
rating of 91 or higher is recommended. The
performance gained by using premium fuel
is most noticeable in hot weather as well
as other conditions, for example when
towing a trailer. See Towing (page 257)."

msgtord

I just downloaded the 2015 owners manual and this is what I read.

[QUOTE2.7L and 3.5L EcoBoost Engines
We recommend regular unleaded gasoline
with a pump (R+M)/2 octane rating of 87.
Some stations offer fuels posted as regular
with an octane rating below 87, particularly
in high altitude areas. We do not
recommend fuels with an octane rating
below 87.
To provide improved performance, we
recommend premium fuel for severe duty
usage, such as trailer tow. [/QUOTE]

idrive

iTrader: (3)

Well it would seem obvious that FORD has changed their tune and it should be obvious that 91 (or higher) is best for overall performance.

The reason they even mention or suggest using 87 is because it makes the cost of ownership less. Apparently that's not as important anymore compared to performance.

Driver8

I used to run 87 and experienced the driveline shudder. Switching to 93 has eliminated the shudder. Just my own experience, YMMV.

WestOGuy

I know this thread is for 2017 3.5, but my understanding is that the 2018's have the same engine, and they say the same thing in 2018, that these engines obtain best overall performance on premium fuel with a rating of 91 or higher.

It should also be noted that you should not attempt to measure fuel economy during the first 1,000 mi (1,600 km). More accurate measurements occur after 2,000 mi (3,200 km). But many of you probably already know that.

After reading this, I plan to start running premium and see how it runs for a few months. I've already gotten over 125 mi on the truck so far!

Here's what's in the 2018 Manual:

Your vehicle is designed to operate on
regular unleaded gasoline with a minimum
pump (R+M)/2 octane rating of 87.

Some fuel stations, particularly those in
high altitude areas, offer fuels posted as
regular unleaded gasoline with an octane
rating below 87. We do not recommend
these fuels.

For best overall vehicle and engine
performance, premium fuel with an octane
rating of 91 or higher is recommended. The
performance gained by using premium fuel
is most noticeable in hot weather as well
as other conditions, for example when
towing a trailer. See Towing (page 276).

Over.