Higher Octane Gasoline

[indadman]

With gasoline prices being extremely low, I decided to run mid-grade Exxon and Shell gasoline in my bike. It seemed to make the bike a bit quicker, with a little more pep. It could just be my imagination, but I don't think so.

Has anyone else tried moving up to higher octane gasoline, and are there any opinions as to whether such a move can impact performance? I'm eager to hear from you.

[2wheelsforme]

Your imagination! Octane is a measurement of resistance to knock and nothing to do with better or higher quality fuel. Now if you want you might see something in alcohol free fuel. https://www.consumer.ftc.gov/articles/0210-paying-premium-high-octane-gasoline/

[Ewreck]

I run 91 all the time and I doubt there’s any HP increases.

[ReserveBum]

In our area there is a convenience store that stocks ethanol free 91 octane. Using regular 87 octane I get @ 40-41 mpg and the bike runs fine. Occasionally I'll use the ethanol free 91 octane - my mileage goes up to @44 for that tank and it feels a little more powerful

[F6Bster]

I run regular unleaded in my 2016 F6B and have never had a knock. But most of my riding is above 5000 feet. Our unleaded at these higher elevations 85 octane (possible because of the thinner air) and never a knock. Now, if I went down to lower elevations that could change. On my 2002 Wing when at lower elevations and on a really hot day I would get knocking when I cranked the throttle, so I would use a higher octane in those situations to avoid the knock. I think 2wheelsforme has it right!

[F6Dave]

I run regular unleaded in my 2016 F6B and have never had a knock. But most of my riding is above 5000 feet. Our unleaded at these higher elevations 85 octane (possible because of the thinner air) and never a knock. Now, if I went down to lower elevations that could change. On my 2002 Wing when at lower elevations and on a really hot day I would get knocking when I cranked the throttle, so I would use a higher octane in those situations to avoid the knock. I think 2wheelsforme has it right!

My experience is similar. My 2016 has never knocked. I run 87 octane ethanol free most of the time, which is available 2 miles from my house. But I used to own a 2013 F6B that knocked on hot days. I remember one very hot day in particular. When I accelerated, I could hear the knock come and go several times. It happened very quickly, maybe over a second or two. I suspect the knock sensors signaled the engine management computer to retard the timing, and that process cycled a few times to get things right. It may have been a bad tank of gas, but in the future I always used premium on very hot days with that bike.

Some high performance cars, like Shelby Mustangs, state their claimed horsepower is reduced when anything but premium is used. I don't think they can actually measure the octane, so I assume they just retard the timing as soon as knocking is detected. I'd be curious if anyone knows more about this. Regardless, with the federal mandate that any new vehicle must 'run' on 87 octane, there are definitely some high performance engines that do make more power with higher octane gasoline.

[rdbonds]

ReserveBum - I agree with your assessment about ethanol-free gas providing better fuel economy. Ethanol has a lower BTU/lb energy content than gasoline. Running fuel without it translates to having more power-dense fuel. On vehicles that can use E85, it takes significantly more fuel to make the same power levels as on E10 gas. The turbo tuning crowd really likes E85 since the ethanol burns is more resistant to detonation and therefore you can run higher boost...but you have to run larger injectors to get enough into the engine.

I agree that running higher than specified octane is a waste UNLESS the engine has been pulling timing due to diagnosed misfires, in which case the absence of those will return the fuel/timing to normal and generate more power as a result.

[valkmc]

Here in central Flogida I can get ethanol free 91 at multiple stations. I use it some and it makes a slight mpg difference but not much. Doesn't matter what I use I very seldom break the 40's. I am normally 36-38 mpg!

[wjduke]

I’ll be honest. I buy the cheapest gas I can find, usually, not always. Always just regular, never any higher octane. Never once heard a knock, no matter the fuel. That’s either one of the F6B’s I’ve owned too.

[SeaSteve]

I would disagree with "cheapest" gas. I fill regular but only the top tier brands like Exxon, Shell, Chevron, etc. Supposedly/Hopefully detergents are added for the few more pennies per gallon than I'd get at Walmart's stations.

[Audiochris90]

I have always tried to use 89. There was an in depth thread years ago on this forum about it. I remember the benefit was gas mileage. I think in owners manual it recommends 89 for a 2016 F6b.

[2wheelsforme]

Honda says use 86 or higher. Most regulars are 87 so fine. I thought it was agreed in this thread higher octane does nothing toward better performance or mileage. Only needed if you experience pinging or recommended by the manufacturer as does BMW and HD.

[ReserveBum]

Honda says use 86 or higher. Most regulars are 87 so fine. I thought it was agreed in this thread higher octane does nothing toward better performance or mileage. Only needed if you experience pinging or recommended by the manufacturer as does BMW and HD.

Dont believe thats true...I get 3 mpg or better using 91 ethanol free over standard 87

[Ewreck]

I would disagree with "cheapest" gas. I fill regular but only the top tier brands like Exxon, Shell, Chevron, etc. Supposedly/Hopefully detergents are added for the few more pennies per gallon than I'd get at Walmart's stations.

Sometimes.

[2wheelsforme]

Dont believe thats true...I get 3 mpg or better using 91 ethanol free over standard 87

I agree with the ethanol free is better. The octane is what makes no difference.

[SeaSteve]

I think paying more at the pump, causes riders to ride slower and save gas.;)

There's a big difference in MPG when doing 80+MPH on I-10 compared to 70 on other highways.

[F6Dave]

Actually, as the octane in gasoline increases, the energy content (BTU/gallon) drops slightly. It isn't enough to make a measurable difference in performance or mileage.

Since higher octane gasoline contains no more energy, it can only increase performance by allowing an engine to run more efficiently, usually via higher compression and/or advanced ignition timing.

[unsub]

With gasoline prices being extremely low, I decided to run mid-grade Exxon and Shell gasoline in my bike. It seemed to make the bike a bit quicker, with a little more pep. It could just be my imagination, but I don't think so.

Folks will bring out data to disprove your observation, but I also feel it's beneficial to up the octane. Don't get sucked into a debate just enjoy the performance.

[DarkKnt]

Folks will bring out data to disprove your observation, but I also feel it's beneficial to up the octane. Don't get sucked into a debate just enjoy the performance. Yup, don't let physics and science interfere with your opinion....

[F6Dave]

Back in the '50s major oil companies ran ad campaigns promoting the amazing benefits of high octane gasoline. I doubt they ever dreamed those ads would create myths that would last for generations. Even the story about the 100 MPG carburetor oil companies paid to keep a secret eventually faded away.

Pure gasoline has roughly 114,000 BTUs per gallon. E10 has a few thousand less. If an engine is running properly on fuel with enough octane to prevent detonation, it is physically impossible for a higher octane fuel with the same energy content to somehow 'find' additional horsepower.

Maybe we need to think about it this way. A modern engine is designed to generate a certain amount of horsepower. If you feed it crappy gas, the engine management computer will detune the engine to prevent damage, resulting in less horsepower. When you switch back to fuel the engine was designed for, the engine will run optimally, and you'll 'get back' the power you lost with the crappy gas.

[Frye]

Assuming our bikes have one or more "knock sensors" could the increased mileage most experience with higher octane fuel be caused by the knock sensors adjusting our ignition timing when using lower octane fuel?

[2wheelsforme]

7495

[Frye]

7495

Yeah I know. Call me Mr. Obvious. :D

[indadman]

Yeah I know. Call me Mr. Obvious. :D

That would be "Captain Obvious!" But aren't we all.

Earlly next Thursday, I am heading from Dallas to Gallup, NM. Will be staying in a hotel on Route 66. Then on to Phoenix to visit an old football teammate. I'm not excited at all!

[Frye]

Assuming our bikes have one or more "knock sensors" could the increased mileage most experience with higher octane fuel be caused by the knock sensors adjusting our ignition timing when using lower octane fuel?

So if this is the case, then it's entirely possible/probable that higher octane gas which doesn't trigger the knock sensor does indeed produce more HP and/or torque than lower octane fuel? Again, this may be obvious but since there seems to be a lot of debate concerning better performance with higher octane fuel I thought it best to spell it out.

[Az Wingrider]

Back in the '50s major oil companies ran ad campaigns promoting the amazing benefits of high octane gasoline. I doubt they ever dreamed those ads would create myths that would last for generations. Even the story about the 100 MPG carburetor oil companies paid to keep a secret eventually faded away.

Pure gasoline has roughly 114,000 BTUs per gallon. E10 has a few thousand less. If an engine is running properly on fuel with enough octane to prevent detonation, it is physically impossible for a higher octane fuel with the same energy content to somehow 'find' additional horsepower.

Maybe we need to think about it this way. A modern engine is designed to generate a certain amount of horsepower. If you feed it crappy gas, the engine management computer will detune the engine to prevent damage, resulting in less horsepower. When you switch back to fuel the engine was designed for, the engine will run optimally, and you'll 'get back' the power you lost with the crappy gas.

This post from F6Dave is correct. Our bikes are designed to run on 86 octane gas and higher octane does nothing to improve power or mileage. If running higher octane gas makes you feel better that's fine but the F6B doesn't require it. I will continue riding with regular unleaded of at least 86 octane as I have with this bike and five previous Honda GLs.

Az Wingrider

[Johnharris]

An engine with a higher combustion head will develop more power then an engine with low combustion of the same size. Hi octane fuel is used only to keep from pre ignition and the added power is only because of the higher compression not the fuel octane. During WW II the p-51 mustang had quite a bit more power (hp) then the ME 109 even though the 109 had larger displacement. The P 51 Had a higher compression engine and had to run on 150 grade fuel while the 109 used 87 because of the inability of Germany to manufacture better fuels. High octane fuel actually have a higher ignition point. I try to use ethanol free fuels because I live right on the coast and it help avoids absorbing moisture into the tank.

[bob109]

This post from F6Dave is correct. Our bikes are designed to run on 86 octane gas and higher octane does nothing to improve power or mileage. If running higher octane gas makes you feel better that's fine but the F6B doesn't require it. I will continue riding with regular unleaded of at least 86 octane as I have with this bike and five previous Honda GLs.

Az Wingrider

Mother Honda designed and built a marvelous machine in the F6B! They continuously apply the KISS Method to their Engine Technology (except for changing the air filter)! They provide the initial 36k warranty and recommend 86/87 Octane fuel! Why folks insist they know more than the manufacturer has always puzzled me! If you feel higher octane is necessary for "your machine" then go for it! I personally prefer to stop at just about any "high volume gas station" fill my tank and ride on! Life is too short to split hairs on octane:cheers: