Ecoboost MPG
It's all speculation, but since you know what octane is and does, then for 2017 it makes sense that premium higher octane fuel would provide more power. In 2017 they increased HP and torque for the same displacement motor... which most likely means a higher compression ratio or boost level (conditions where higher octane helps prevent pre-detonation).
Actually, the 2016 manual also 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.
Ethanol, octane and corrosion - Biofuels Association of Australia
Which is why many fueling stations mix it into their 'premium' (it's not, that's just a marketing word) gasoline in order to achieve the octane they want.
Problem is, alcohol (ethanol) has a lousy energy content.
With only 2/3 the energy of gasoline, ethanol costs more per mile - zFacts

Don't know why this is so hard to understand.
You can achieve a higher octane rating without ethanol in it but it's more expensive to do it. THAT is what we call 'Premium' fuel
As of 2016, the US imported 25% of the petroleum it consumed, which was the lowest level since 1970. Of that 25%, we got 38% from Canada and 11% from Saudi Arabia. So how come we're still adding ethanol to our gas? Well one reason is because when the government buys off the farmers its impossible to stop. Maybe its for the same reason we subsidize tobacco farmers while spending billions on anti-smoking programs.
Lately there was talk of upping the ethanol content from 10% to 15% but that has been put on temporary hold after it was pointed out that that would cause billions of dollars in damage to non flex-fuel vehicles. Maybe that was the idea. Why else would the government want to REDUCE the fuel mileage of cars?
Another interesting possibility is that since ethanol reduces the mpg of internal combustion engines, it makes hybrids and all-electric vehicles look more attractive. It seems that right now electric-only vehicles are the holy grail of the tree hugger set. "Just look, honey, we're not generating any pollution at all! We're so green!" Tell it to the guy who lives down the road from the generating plant somewhere in the mid-west. But wait, you say. We'll generate all the electricity we need from renewable sources like wind and solar - as long as you don't build the wind or solar farm where I can see it!
Lets face it. The internal combustion engine is going to be with us for a while yet. Decrease the displacement. Increase the compression ratio and turbocharge the daylights out of it. Oh, and get the ethanol out of the fuel!
Let the ranting and raving begin........
I'll keep better track of the next few tanks.
Ethanol, octane and corrosion - Biofuels Association of Australia
Which is why many fueling stations mix it into their 'premium' (it's not, that's just a marketing word) gasoline in order to achieve the octane they want.
Problem is, alcohol (ethanol) has a lousy energy content.
With only 2/3 the energy of gasoline, ethanol costs more per mile - zFacts

Don't know why this is so hard to understand.
You can achieve a higher octane rating without ethanol in it but it's more expensive to do it. THAT is what we call 'Premium' fuel

High compression engines normally need higher octane to prevent knocking. If your computer senses any knocking, it will retard the timing and lower performance. I suspect it isn't needed in 99.999% of driving.
In looking at the farming subsidies and gov't giveaway to farmers...your delusional if you think it's still about lowering our oil imports. We have all the cheap crude we can use right now. The strategic oil reserves are full. Frankly, it's about the lobbyist getting their way with politicians and the politicians giving them the subsidies to buy votes. That's it.
Fortunately, ethanol does have approx 2/3 the energy density of gasoline. It's commonly mixed at 10%. So your getting about 96-97% of the energy in your tank as compared with ethanol-free fuel.
High compression engines normally need higher octane to prevent knocking. If your computer senses any knocking, it will retard the timing and lower performance. I suspect it isn't needed in 99.999% of driving.
In looking at the farming subsidies and gov't giveaway to farmers...your delusional if you think it's still about lowering our oil imports. We have all the cheap crude we can use right now. The strategic oil reserves are full. Frankly, it's about the lobbyist getting their way with politicians and the politicians giving them the subsidies to buy votes. That's it.
Fortunately, ethanol does have approx 2/3 the energy density of gasoline. It's commonly mixed at 10%. So your getting about 96-97% of the energy in your tank as compared with ethanol-free fuel.
In doing so, they lower the energy content of the gasoline.
If your vehicle is made to burn to ethanol, you have no worries other than lousy fuel economy and a hole in your wallet. If it isn't, it could cause premature wear on your engine.
The EcoBeast doesn't like ethanol. It is NOT Flex Fuel rated.
Don't know why, exactly. Don't really care.
Just trying to help.
But yes, I said in here several times that if you're working your truck hard and it starts to knock, your ECM will retard the timing to stop it from knocking. That kills fuel economy but it's better than harming your motor.
If you run higher octane fuel, it will slow/stop the knocking and the ECM won't have to retard the timing. But at a price. Higher fuel pricing (a lot these days) worse fuel economy and running higher percentage of ethanol through an engine that doesn't really like it.
If you need to burn premium all the time because of the load you're putting your F-150 under, you might want to consider a Super Duty. But if you're like most of -- Pull the boat now and then, pull a camper now and then, do a little light work around the hacienda/family small farm and the rest of the time, use it as a grocery getter, you're just throwing money away on fuel that isn't all that great for your EcoBeast motor.
And yes, the more expensive fuels usually do have better additives...... More detergents, etc. So running a tank full of 'premium' through your engine once or twice a year isn't a bad idea.
Some car makers think that by burning the more expensive fuel they can avoid the embarrassment of the car owners having to get their heads walnut shell blasted every now and then -- BMW, Acura, Audi and others that use Direct Injection........ And Ford
It doesn't work. The fuel never sees the intake ports. Which is why Ford is going to two injectors per piston on their Direct Injection Engines this year. To keep the intake ports clean.
Point is, 'premium' fuel is usually just a waste of money. Not always. If you need it, you need it. If you don't, you're just throwing money away
What others have said regarding octane is true. The higher the octane, the lower the energy value per unit volume of fuel. 87 octane has more energy per gallon than 89 octane, which has more energy value per gallon than 91 octane, and so on. Diesel has more energy value than gasoline of any grade.
However... Energy value does not equate directly to performance. A higher octane rating will allow higher compression without detonation, and will also allow more timing advance because higher octane will burn slower. The slower burn ensures that the flame propagates in a more controlled manner, and ensures that it all gets burned.
Different grades (octane rating) of fuel are pretty much the same across brands. I know in the San Francisco Bay area, all the fuel trucks from all brands fill their trucks from the same pipes. The grades are all identical.
However, different brands put additives in the truck before delivery. Each brand has different additives, and different amounts of additives. Most of the additives are detergents that help clean valves and intake surfaces. The additives are a small amount of the total; less than 1%. I know the recommended level of Techron (Chevron) is about 1 oz of Techron per gallon. So in that specific case, the fuel is 99.2% of the total, and the Techron is 0.8%.
To learn about top tier gasoline check this link: 8 things to know about Top Tier detergent gasoline | Clark Howard
What others have said regarding octane is true. The higher the octane, the lower the energy value per unit volume of fuel. 87 octane has more energy per gallon than 89 octane, which has more energy value per gallon than 91 octane, and so on. Diesel has more energy value than gasoline of any grade.
However... Energy value does not equate directly to performance. A higher octane rating will allow higher compression without detonation, and will also allow more timing advance because higher octane will burn slower. The slower burn ensures that the flame propagates in a more controlled manner, and ensures that it all gets burned.
Different grades (octane rating) of fuel are pretty much the same across brands. I know in the San Francisco Bay area, all the fuel trucks from all brands fill their trucks from the same pipes. The grades are all identical.
However, different brands put additives in the truck before delivery. Each brand has different additives, and different amounts of additives. Most of the additives are detergents that help clean valves and intake surfaces. The additives are a small amount of the total; less than 1%. I know the recommended level of Techron (Chevron) is about 1 oz of Techron per gallon. So in that specific case, the fuel is 99.2% of the total, and the Techron is 0.8%.
To learn about top tier gasoline check this link: 8 things to know about Top Tier detergent gasoline Clark Howard
At the end, you'll see where I mention automakers have been lobbying for a higher octane fuel standard to allow them to push the envelope further and get more power from less displacement. I'm posting it here because it's related to the conversation and I think you guys might find it interesting
Some more fun stuff: Ford uses different octane fuel for their horsepower test than they do for their gas mileage test....
From FordNXT:
Upon closer examination, it was revealed that the Lincoln MKX with the 2.7 liter EcoBoost engine was tested using 93 octane for its horsepower rating, but 87 octane with 0% ethanol for its fuel economy sticker.
Ford used 93 octane to arrive at the horsepower figures of the 2015 Mustang, we should note.
From Motor Authority:
UPDATE: A Ford spokesman has explained that while horsepower in the Mustang EcoBoost will be down when using 87 octane fuel, as will be the case with virtually any engine when using a fuel with a lower octane rating than the recommended level (in this case 93), the torque figure is unchanged at 320 pound-feet. Below is the full comment:
“We’ve no notion where this graphic originated, but if real, it may have been produced (as many training materials are), before final power certifications were complete. It is incorrect as the torque figure of 320 lb-ft does not change when using 87 octane fuel in the EcoBoost Mustang (lower octane fuel generally only affects horsepower numbers which occur at higher rpm). The 2.3-liter EcoBoost produces its rated power of 310 horsepower using its recommended fuel (93 octane), and like all modern engines, will proactively adapt to a lower octane fuel mixture. We publish power figures based on our recommended fuels, but peak horsepower would be reduced when using a fuel with a lower-than-recommended octane rating.”
Early reports of the 2015 Ford Mustang EcoBoost hinted at the notion that the power figures would be significantly lower when an owner filled up with 87 octane fuel. When running the good stuff, the EcoBoost engine produces 310 horsepower and 320 pound-feet of torque. Should you decide to fill up with 87, you can expect a power output of 275 horsepower and 300 pound-feet of torque, at least that's according to a Ford training manual obtained by Mustang6G.
There is a lot of interesting stuff to read if you Google "Ecoboost octane test"
I even found an article that stated the EPA is being lobbied by automakers to increase the octane ratings of available fuels. Apparently, today, modern computers in our cars do adjust on the fly for octane...and to make more power per displacement....they need higher octane fuels [than you get at the corner gas station today].
Ford Trucks for Ford Truck Enthusiasts
All top tier fuel has more additives than those that aren't top tier.
Ford recommends premium when towing and or it's hot as the ecoboost will dump fuel to help cool the cylinders when its hot.
Conventional Area
Any area that does not require the sale of reformulated gasoline. All types of finished motor gasoline may be sold in this area.
Conventional Gasoline
Finished motor gasoline not included in the reformulated gasoline category. Excludes reformulated gasoline blendstock for oxygenate blending (RBOB) as well as other blendstock. Note: this survey designates all motor gasoline collected within a conventional area as conventional gasoline (see conventional area).
Gasoline Grades
The classification of gasoline by octane ratings. Each type of gasoline (conventional and reformulated) is classified by three grades - regular, midgrade, and premium. Note: gasoline sales are reported by grade in accordance with their classification at the time of sale. In general, automotive octane requirements are lower at high altitudes. Therefore, in some areas of the United States, such as the Rocky Mountain States, the octane ratings for the gasoline grades may be 2 or more octane points lower.
Low Sulfur Diesel Fuel
Diesel fuel containing more than 15 but less than 500 parts per million (ppm) sulfur.
Midgrade Gasoline
Gasoline having an antiknock index, i.e., octane rating, greater than or equal to 88 and less than or equal to 90. Note: Octane requirements may vary by altitude.
Nonattainment Area
Any area that does not meet the national primary or secondary ambient air quality standard established by the Environmental Protection Agency for designated pollutants, such as carbon monoxide and ozone.
On-Highway Diesel
Includes sales for use in motor vehicles. For purposes of this survey, it is designed to estimate the retail cash price of self-serve, motor vehicle diesel fuel.
OPRG
"Oxygenated Fuels Program Reformulated Gasoline" is reformulated gasoline which is intended for use in an oxygenated fuels program control area during an oxygenated fuels program control period.
Petroleum Administration for Defense District (PADD):
PADD 1 (East Coast):
PADD 1A (New England): Connecticut, Maine, Massachusetts, New Hampshire, Rhode Island, Vermont.
PADD 1B (Central Atlantic): Delaware, District of Columbia, Maryland, New Jersey, New York, Pennsylvania.
PADD 1C (Lower Atlantic): Florida, Georgia, North Carolina, South Carolina, Virginia, West Virginia.
PADD 2 (Midwest): Illinois, Indiana, Iowa, Kansas, Kentucky, Michigan, Minnesota, Missouri, Nebraska, North Dakota, Ohio, Oklahoma, South Dakota, Tennessee, Wisconsin.
PADD 3 (Gulf Coast): Alabama, Arkansas, Louisiana, Mississippi, New Mexico, Texas.
PADD 4 (Rocky Mountain): Colorado, Idaho, Montana, Utah, Wyoming.
PADD 5 (West Coast): Alaska (North Slope and Other Mainland), Arizona, California, Hawaii, Nevada, Oregon, Washington.
Premium Gasoline
Gasoline having an antiknock index, i.e., octane rating, greater than 90. Note: Octane requirements may vary by altitude.
Reformulated Area
An ozone nonattainment area designated by the Environmental Protection Agency which requires the use of reformulated gasoline. Includes oxygenated fuels program reformulated gasoline (OPRG).
Reformulated Gasoline
Finished motor gasoline formulated for use in motor vehicles, the composition and properties of which meet the requirements of the reformulated gasoline regulations promulgated by the U.S. Environmental Protection Agency under Section 211(k) of the Clean Air Act. (Details on this clean fuel program). This category includes oxygenated fuels program reformulated gasoline (OPRG) but excludes reformulated gasoline blendstock for oxygenate blending (RBOB). Note: this survey designates all motor gasoline collected within a reformulated area as reformulated gasoline (see reformulated area).
Regular Gasoline
Gasoline having an antiknock index (average of the research octane rating and the motor octane number) greater than or equal to 85 and less than 88. Note: Octane requirements may vary by altitude.
Total Gasoline
Includes all finished motor gasoline grades (regular, midgrade, premium) and formulations (conventional, reformulated).
Ultra Low Sulfur Diesel Fuel
Diesel fuel containing a maximum 15 parts per million (ppm) sulfur.












