gas octane question for PB F150

[stlgrym3]

do you guys use the low octane (87 in socal) or 91 and above for your PB F150? if you use low octane gas, does it have negative affect to the range?

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[Gros Ventre]

I cannot discern a difference in MPG between 87 & 91/93 octane. That is what the Otto Cycle engine design should show, higher octane only give you more power if the engine compression ratio is higher. The benefit of using higher than 87 octane will occur in the summertime (eg hot) when you're towing a heavy load up a steep and extended grade (eg South Pass in Wyoming). The higher octane will provide a bit more margin from detonation.

 

[Snakebitten]

A pretty common question.

I personally think as a strictly $-based value equation, 93 octane VS 87 octane is a tough challenge for the high octane crowd. (of which I belong admittedly)

According to all the data, the Ecoboost engine management does in fact leverage the additional octane rating with additional timing advance. That does create additional torque for the same quantity of fuel and so it delivers additional mileage per gallon, all else being equal.

But enough additional mileage to overcome the additional co$t per gallon? That would definitely depend on the price delta. Usually not.

Still, I pay the price for 93. I enjoy the data on the gauges that I monitor (PIDs) and tell myself the motor is telling ME it's enjoying the good life.

 

[Tosh]

Ford's power ratings are derived using high octane gas

I prefer 91 (or higher) octane under all conditions

 

[Snakebitten]

Ford's power ratings are derived using high octane gas

I prefer 91 octane under all conditions

It wasn't always.
In 2018, the small print on Ford's 3.5 Ecoboost ratings for the Raptor stated 93 octane. For the non Raptor it stated 87.

I don't know what it is currently, but as you stated, maybe it's all 93 now.

 

[dhrandy]

Ford's power ratings are derived using high octane gas

I prefer 91 (or higher) octane under all conditions

Lol, I've only ever put 87 in. Even when towing.

 

[Snakebitten]

Lol, I've only ever put 87 in. Even when towing.

While Ford fully supports running 87 in the Powerboost, they also state 91 for towing? (at least that's what I recall)

Edit:

 

[Davexxxx]

I am so not, a petroleum engineer and fuel differs by parts of the country. For instance, I can't get ethanol free gas, short of paying ~50% more and having quite a drive to get it. Whereas others have no such problems.

And I could be very wrong but was once told by someone who did know, is that the main way of adding octane, is increasing the amount of alcohol. This too, might differ depending on where you are, IDK.

Not that while towing, you're likely to have much left over to get stale.

Anyway, I'll probably just follow what the manual says.

 

[dhrandy]

While Ford fully supports running 87 in the Powerboost, they also state 91 for towing? (at least that's what I recall)

I'm aware, but I'm also only towing between 4000 and 5000 lbs.

 

[mnstang]

I've only used 87 in my Powerboost. I realize that the manual recommends 91 octane, but I have found no detrimental effects with using 87. Although in MN, ethanol is added and required, so YMMV, literally.

 

[nrmedic]

I utilize E10 93. I had occasional spark knock with 87.

 

[Gros Ventre]

It's not at all clear that advancing the spark enables more power. The purpose of spark advance is to ensure complete combustion and max cylinder pressure at TDC from the burning of fuel. In other words there is no more energy extracted by advancing the spark because of higher octane. The basic Otto Cycle only extracts more power if there is a higher compression ratio and higher octane fuel enables use of that by compressing the mixture more without detonation. If you advance the spark beyond the complete combustion point, you get pinging & knocking since you are now compressing a fully burned (& far higher pressure) mixture.

 

[wrgrimes]

I use non-alcohol 91 Octane, about the same price as 93 Octane.

 

[UGADawg96]

87 when not towing and 93 when towing our 6500lb TT. We try to plan ahead knowing when we're going to be towing to wean down the current tank, but don't always get 100% switch. Have towed with only 87 and have daily driven with 93. Just giving it the old college try. I have no idea what impact it has really.

 

[Calson]

Every vehicle produced in the past 30 years has an auto retard capability to prevent pre-ignition and knock that can damage the engine. Higher than the specified octane rating fuel provides zero gain but does help the profits of struggling companies like Exxon and Shell and Chevron.

For some reason all these developments over the past 50 years in engine technology have escaped most people. Follow the recommendations on the stickers on the vehicle and in the owner manual and then you will have no worries and not waste your money.

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