I used 89 octane and my MPG has gone up 3 ticks already

[Aspidochelone]

I thought you just weren't supposed to put higher octane fuel in than is specified. Is this some old myth?

The manual recommends 91 or higher but says that 87 is fine. You just have to read farther down. Higher octane isn't likely to hurt you just don't want to put low octane in a vehicle tuned for high octane because you can blow up the engine.
The maverick is probably tuned for a higher octane fuel.

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[Montana]

$0.35 difference where I live between 87 and 91, and 120 miles away in the bigger town it's .60 difference at it's highest.

Less than $4 per fill up and I average 2-3 MPG better.

Ecoboost so I'll be spending that loot for it. Even when I had my 2.5L Hybrid Escape the difference was there.

If I was that worried about it, I'd buy a Prius since my main compromise would be cost at the pump. Thankfully, it's not.

 

[jpv74]

That was some interesting info about how gas gets to my station. I do prefer Shell gasoline. Even after that long explanation about gas and octane I know my truck is running better on this higher octane fuel. Again I am only jumping from 87 to 89, some others are chatting about 91 which I will not use in my hybrid. I drove for a couple of hours around town today and sure enough the mpg is now up from avg 44.3 to 44.9. By the time I am done with this tank my average could hit 46mpg. With my truck running and performing optimal and my mpg going up and up I think this is a no brainer.

 

[Scooter66]

Yes, it is a myth

The engine has a 10 to 1 compression ratio so to reduce knock the engine adjusts the timing with cam- phasers. Best to just use the 93 octane all the time and let the engine run at the optimal timing for power.

 

[RedRider]

Just a quick hitter here folks. I understand the truck was designed to run on 87 but I have given her 89 octane twice and both times she definitely runs a little peppier and my MPG went up. Now in my area there is a substantial difference for 87 or 89 octane gas per tank so I have to decide if its worth it. My over all feel is that the truck will have less carbon build up and her internals will be cleaner on higher octane fuel. My truck is a 23 XL hybrid

LOL. That just means that you drive with a very heavy foot, with no idea how to just cruise. The extra octane will delay the point where it backs off the timing. As for less carbon, I seriously doubt it. With your heavy foot I would expect more carbon, not less. The only thing that reduces carbon buildup in any meaningful way is using top-tier fuel.

 

[Rileyotta]

Just a quick hitter here folks. I understand the truck was designed to run on 87 but I have given her 89 octane twice and both times she definitely runs a little peppier and my MPG went up. Now in my area there is a substantial difference for 87 or 89 octane gas per tank so I have to decide if its worth it. My over all feel is that the truck will have less carbon build up and her internals will be cleaner on higher octane fuel. My truck is a 23 XL hybrid

I thought the 2.0 recommended premium(91 octane)?
I’ve noticed much better mileage and performance/responsiveness with premium fuel vs regular.

 

[EchoPear]

$0.35 difference where I live between 87 and 91, and 120 miles away in the bigger town it's .60 difference at it's highest.

Less than $4 per fill up and I average 2-3 MPG better.

Ecoboost so I'll be spending that loot for it. Even when I had my 2.5L Hybrid Escape the difference was there.

If I was that worried about it, I'd buy a Prius since my main compromise would be cost at the pump. Thankfully, it's not.

Man that’s so nice! It’s like over a dollar difference between regular and premium where I am

 

[Ranch]

 

[Old Ford Guy]

What you see might not be a result of the octane difference, but rather how much Ethanol is in the different fuels you are using. Fuels containing Ethanol have less energy per gallon, so if your higher octane fuel has less ethanol, that might be why you are getting better mileage.

You have hit on the main reason people see a small MPG bump when using higher octane fuels. if a given fuel contains 10% ethanol it follows that a zero % ethanol fuel should deliver 10% more energy. but this does not mean you suddenly get a 10% improvement in mpg or performance, its not a linier correlation.

also when considering which fuel to use dont sleep on the long term benefits of using 'Top Tier' gas. this is gas blended with additional additives that cut down on carbon build up and other good things. most big box discount gas stations usually dont carry top tier gas, as it is a voluntary industry standard that exceeds the federal govt standards for this kind of stuff. youll typically pay an extra .05 to .10 cents p/g for this fuel.

the engine in our hybrid was designed to operate jus fine using 87 octane and the miniscule performance/mpg boost you may receive isnt worth the extra expense to me but to each their own, its your truck after all, feel free to feed it whatever you wish.

 

[surfstar]

but, butt-dynos never lie!

I can "feel" it run smoother and "feel" it respond quicker with ____

 

[inthecabin]

Yeah ours gets at least 3 or 4 mpg better on 91. 10% cost increase for 12.5% mileage increase is good enough for me.

this reminds when I lived in Washington state when recycling aluminum was 72 cents/pound and my friend was buying lead shot at 96 cents/pound and adding it to his aluminum cans to get more money recycling… I really tried showing him his errors but to no avail.. you’re math is solid..

 

[Old Ford Guy]

Octane is determined by two different measurements of how well a fuel resists premature combustion under pressure - the "research" octane number and the "motor" octane number. The "average" octane rating is what you see at the station (R+M/2).

When you pay for a higher octane you're paying for a fuel that is more resistant to combustion under pressure and is thus able to be compressed more in the cylinder. Higher combustion engines (like those with turbochargers) have higher compression ratios - higher compression ratio's require higher octane.

Putting low octane gasoline in a high compression engine will result in engine knock (i.e. your gasoline exploded before the cylinder fully compressed). Putting high octane gasoline into a regular compression engine won't really do all that much. Yes, maybe your engine computer will detect the difference and adjust accordingly but it won't make that much of a difference. So there is a LOT of downside risk, but little upside benefit for the cost.

In a quest for higher efficiency and power from smaller engines, more auto manufactures are making small turbocharged engines that they test and certify on mid-grade or premium for their EPA MPG tests etc. but also build them to run on regular. They're afraid of people's reaction to "Premium Required" when car shopping, so they instead label them as "Premium Recommended". So you can fill up with regular, and it will run fine, but you won't get the performance as advertised. ( I have a hybrid so I do not know what the Ecobost is rated for)

Also note - the octane rating of the gasoline has nothing to do with the "quality" of the fuel.

Gasoline is "fungible" and only varies on octane and it's destination market. That's to say the gasoline that comes out of Refinery Y and Refinery X destined for the same marked - are for all practical and reasonable purposes - chemically identical. They are comingled in petroleum product pipelines and then shipped across the country. There are some variances for emissions and pollution (like California has it's own gasoline formula). But for the most part it's all the same.

At the distribution terminals - or "rack" - proprietary detergents and chemicals are added to the gasoline just before it is loaded onto a tanker truck for deliver to a retail station. So in other words, your "Shell" gasoline only becomes a "Shell" gallon right before getting loaded onto the tanker truck.

At the rack is also where they add ethanol to most retail gasoline. Yes, most gasoline made at a refinery is sub-octane, and will only hit octane requirements with a splash of corn alcohol.

If you see a station with a tanker truck delivering gasoline, keep driving to another station. In the process of refilling, sediments that have fallen to the bottom of the underground tanks can be disturbed and make their way to the pumps.

Otherwise, regular, mid, or premium gasoline is of the exact same quality - with only one specific chemical specification differentiating them. If you worry about low-quality gasoline, buy a bottle of Seafoam and mix it in when you're filling up on occasion.

The "price premium" for premium is also increasing.

The U.S. Energy Information Administration collects and publishes weekly average retail gasoline prices - by region, grade, and formulation.

Since between 1995-2008, the difference in price for premium was about $0.20/gal. But since ~2009 that premium has only increased. On average across the U.S. for the week of August 14, 2023 - a gallon of premium was $0.83/gal more than a gallon of regular. It was as high as $0.94/gal as recently as October 2022.

So is that extra 2-3 mpg worth the nearly $1/gal extra?

great post1 thats how you break that sh*t down my friend

 

[PlantMan]

I wonder how Sunoco Green E15 98 octane unleaded race fuel would perform? Would my EB get 50 mpg?

 

[Maverickman74]

this reminds when I lived in Washington state when recycling aluminum was 72 cents/pound and my friend was buying lead shot at 96 cents/pound and adding it to his aluminum cans to get more money recycling… I really tried showing him his errors but to no avail.. you’re math is solid..

I figure if it atleast runs a lil cleaner with more zip and breaks even, why not?

 

[LM42]

The engine has a 10 to 1 compression ratio so to reduce knock the engine adjusts the timing with cam- phasers. Best to just use the 93 octane all the time and let the engine run at the optimal timing for power.

I am not the person that needs fuel advice

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