Octane 87, 91 and 93

[Randy Schmidt]

I have exclusively run 87 octane in my Expedition since new. Has anyone run different octane to see if there is an increase in (butt hp)?

 

[Uturn]

I have in ours. Normally run 89 octane, but have run 93. At around 5000 lbs it will be hard to tell the difference. My F350 module steps the HP 25hp at a time and I do not notice it much, bump it to steps(50rwhp) and you can tell. I am trying to get the as built files on a Platinum version 2WD so I can do a ECM comparison. I still have a suspicion that the Limited/XLT's use the same calibrations.

 

[Mike Wolfe]

Interesting question
Ford rates the hp on 93 octane fuel
I have never used anything but premium in my vehicles
Some required it such as the 2008 Nissan Pathfinder with a V8 i had
All the eco boost vehicles (I have owned 5 of them) have been recalibrated with new tuning software to optimize their performance with premium fuel
Makes a huge difference in throttle response etc
Try premium & I would bet you can feel the difference in the SEAT OF THE PANTS acceleration
Will take a couple of tanks to fully flush out the low octane fuel though

 

[MonkeyBrains]

I think that I can tell the difference between 87 and 91 octane. I just use 91 now as it does seem to run just enough better to notice. I don’t know if it helps mileage enough to make up the cost differential though. Never tried 93 as it’s not readily available near me.

 

[18-FX4-GUY]

I just run 91 in mine highest I can get here.

 

[Uturn]

Actually Mike, Ford advertises 375hp on regular unleaded for the XLT's and Limited's, and the Platinum's require 93 octane fuel to achieve the higher rating. This may just be an advertising gimmick, since not everyone wants to spend a lot of money on an Expedition and then have to run premium fuel. Ford may also figure that if you are willing to spend up to 20k more for a Platinum you would also be willing to pay for the premium fuel. There have been issues in the past where a manufacturer has overrated an engine (Mazda Miata) and had to buy some vehicles back. There are some manufacturers that rate the engines on regular fuel, but those engines actually produce more power on premium. A couple examples are the Buick Regal GS with the supercharged 3800 V6 that was rated 240hp, but several were dynoed and the 0-60 times consistently showed 270hp. BMW is another with the 4.4 M62TU engine rated at 282hp accelerating a 3850lb car to 60 in 5.4 seconds. When the cars were dynoed they were putting 270hp to the ground. There are several 0-60 tests now available, but they are all Platinum editions. Until the coding on the Expedition's can be compared or someone actually posts a 0-60 time for a XLT/Limited to compare with the Platinum's tested times we will not know for sure.

 

[shane_th_ee]

There are some manufacturers that rate the engines on regular fuel, but those engines actually produce more power on premium...

From the owner's manual:

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 274).

 

[JExpedition07]

I know the generation 1 ecoboost required 91 octane to produce its rated 365 HP/ 425 torque and ford disclosed that. It will run fine on 87 just a bit less power than 91+ because the timing is retarded.

 

[rumline]

What about MPG differences? Anybody hand-calc their mileage and has measured a difference between running on different octane ratings?

 

[JohnT]

Biggest difference I found was about .5 to .7 l/100km but arguably that doesn't cover the additional cost however up north premium tends not to have ethanol (costco and shell) and typically has more additives so t's a bit of a wash for me. I have gone back to 87 as prices have climbed again but may consider 91 once we get into winter gas.