This has probably been discussed before, but there might be some new owners that could chime in. I'll be towing the travel trailer for the first time this weekend (approx 7K lbs), and was wondering if the stock PCM recognizes and makes any adjustments for higher octane? Or is it just a waste of money? I'll expect to go through two tanks on this trip, and was thinking of burning reg on the first, and prem on the way home just to see if I noticed a diferance. No big hills on this trip, and we're heading to the coast so will be at or near sea level. Only 900 miles on truck so it's not even broke in yet. Anyway, your thoughts? Thanks, and I'll post up a trip report when I get back.

 

Running a gas with higher octane rating than what the engine is designed for does nothing. Higher octane rating only means the fuel is more resistant to compression-detonation.

Now, if the "premium" fuel also has no ethanol in it, that is a different story. Some stations in some states still sell gas without ethanol as a selection at the pump, but it is getting harder to find.

 

This is incorrect.

Running premium in the 6.2 will yield you more hp. This was confirmed by the 6.2 engineer back when he was around answering questions here on FTE.

 

Running higher octane rated fuel than what the engine is designed for alone can not improve HP - it defies physics.

Now, if the "knock sensor" is sensing pre-ignition and retards the ignition timing to protect the engine, HP is reduced. I did not see the q&a with the 6.2 engineer, but maybe that was what he was referring to?

What is the minimum octane rating required for your truck? Does the manual specify different fuels for different conditions?

 

"Octane is defined as a fuel's resistance to knocking. There is no benefit if the octane is higher than what the engine needs. Engine knock occurs when fuel in a combustion chamber ignites before it should. This disrupts the engine's operation. But electronic knock sensors are now common and have nearly eliminated engine disruption." - California Energy Commission Consumer Energy Center

All the research I read over the years on this subject reads almost exactly as this quote summarizes.

I will also throw out there that there is no tangible detriment to running higher octane fuel, other than to your wallet. So I can see why people choose to pay a little extra for the peace of mind.

 

What’s the difference between premium-grade and regular gasoline? • Ask an Engineer at MIT Engineering

Here's an article from MIT on the subject...

 

Here....

https://www.ford-trucks.com/forums/9...ml#post8833938

 

Thanks for that link. So the octane rating recommendation for these motors is purposely understated so the knock sensor controls engine timing more frequently? I did not know manufacturers were doing this.

So does your manual suggest different fuels for different conditions? My newest gas motor is a '08, just curious.

 

Thanks for the replies guys. So the Ford engineer says 10 HP gain. While that's nice, I'm not sure it's worth the extra .30 cents a gallon I have to pay around here for 91. I think I'll stick to the reg this weekend and see how it goes. When I tow in the mountains it might be worth trying though.

 

I Don't remember seeing anything in mine (coulda missed it I'll check when I get home). I know the EcoBoost does.

 

I run E10 87 or 89, in some of the midwest states E10 is reg 87 with 10% ethanol added to makes it 89. Runs just fine on the lower octane is was designed, I see no need to run the higher priced octane gas.

Denny

 

I don't ever recall seeing anything where they recommended different grades of fuel for different conditions, but if you wanted a little extra hp, the option's there.

I'm running a 93 tune so I get more than a little extra hp. My tires are paying for it, already ready for another set before winter sets in.

 

Try Premium Fuel without ethonal. I have tried premium but really couldn't see/feel the benefit. Of course I don't have a tune. Still trying to find a good station locally that has the straight stuff.

 

I notice 1-2 mpg yield difference in the octanes. I put premium in frequently, less trips to the pump.

 

Went ahead and filled up last night with 87. Pretty much everything around me has "up to 10%" ethanol. It was $102.31 when it clicked off at 3.79 a gallon. I think I was wrong about needing two tanks for our trip. It's only around 95 miles to the state park, so might make it on one tank if we don't run around too much. Leaving in a few hours and I'll be off the grid till Sunday night. Later