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Hey everyone, I live in Florida where of course its hot and humid but as I read other post about fuel seems like I should only be using 87 octane. I have a 2020 900 custom which i have always use 97 octane, my question should I only use 87?
 

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I have found my 900 runs poorly on high octane fuel. So I use the 87 octane that is recommended by the manufacturer. Haven’t tried the non ethanol fuel that is available and wonder if would change the performance.
 

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Tourer I have found I get approximately 2-4 mpg better when running non ethanol fuel. After having a lot of issues with ethanol fuel in small engines I only run non ethanol in them and the motorcycle feeling it is cheep precaution.
 

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Tourer I have found I get approximately 2-4 mpg better when running non ethanol fuel. After having a lot of issues with ethanol fuel in small engines I only run non ethanol in them and the motorcycle feeling it is cheep precaution.
That is interesting, spencea15. I have tried 100% gasoline (90 octane) and saw no difference in performance or mileage. However, towards the end of the season, I will start using the 100% gasoline because I don't want the ethanol sitting in my tank over the winter.
 

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The only way to get increased mpgs with increased octane is IF it is pure gas without ethanol.
Using high octane will not increase mpgs. It is only there in the gas to prevent engine knock.

However most pure gas comes in the 90/91 octane set up.
Where in the US you live has nothing to do with which gas to use.
 

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I used pure gasoline, it just happens to come in 90 octane. Any gains would be attributed to the lack of ethanol, not the octane. But to repeat: no performance/mileage gains to be had by switching. But if you are like me and hate all things ethanol, it certainly won't hurt. I also use 100% gasoline for all my small engines. I have had ethanol related issues with them in the past.
 

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Here in Wash. State, 100% gas is offered in about 10% of stations near me. Some at 90/91 octane others at 87octane. My mpgs are much improved with the good stuff, near 50mpg in mixed driving. Always use the lowest octane that will keep engine from pinging(Pre-detonation). Also there is more energy in gas than alcohol.
 

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I used pure gasoline, it just happens to come in 90 octane. Any gains would be attributed to the lack of ethanol, not the octane. But to repeat: no performance/mileage gains to be had by switching. But if you are like me and hate all things ethanol, it certainly won't hurt. I also use 100% gasoline for all my small engines. I have had ethanol related issues with them in the past.
I'm curious as to what your ethanol related issues were. I've been burning 10 E gas in everything I've owned since about 1976 and I don't know of any issues. But then, I don't know what to look for either.
 

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Where I am, we have 87, 89 and 91 grades. -- 87 gas has 10% ethanol, 89 gas has 5% ethanol and 91 gas has no ethanol.

Along with the bike, I also have a Jeep Wrangler and a Hyundai Accent. I've run all the grades through my vehicles and haven't really seen much difference in mileage and performance. Certainly not enough to justify using anything more than 87.
 

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Okay, using the numbers from the Gasoline vs Ethanol chart that was posted above, here are the numbers:

Gasoline (summer blend) ....... 114,500 BTU/gal*
Ethanol Blend (E10) .................. 111,836 BTU/gal

*I even used the summer blend, which has even more energy than base gasoline.

114,500 / 111,836 = 1.024 = 2.4%

So gasoline has 2.4% more energy than E10 Blend gasoline (gasohol).

NOT SO FAST!!!

A typical internal combustion engine is 20% to 35% efficient.
That means, at best, only about a third of the gasoline's energy is converted to mechanical energy, the rest is given off as heat blown out the tailpipe and radiated from the engine.

I'll be kind and assume the VN900 is 30% efficient.

2.4% x 0.3 = 0.72%

So you can expect about a 0.72% increase in power and gas mileage.

Therefore, if you normally get 48 MPG, you can expect a whopping 48.35 MPG which is probably smaller than the accuracy of your measurements.

I guess you can also expect a 0.72% increase in power as well ....

48 HP is now 48.35 HP
58.2 ft-lbs is now 58.6 ft-lbs

... none of which you will never feel.

So, in summary, switching from E10 gasohol to 100% gasoline will yield an insignificant improvement in mileage and performance.

But there are other benefits....

Ethanol requires more energy to produce than gasoline and it takes away from the food supply (corn). Unlike gasoline, ethanol is hygroscopic meaning that it readily absorbs water from the air. If is able to absorb enough moisture, it can cause a phase separation to both ethanol and water. Water is heavier than gasoline or ethanol and it will sit on the bottom of your tank should this occur. Poor starting or no starting can be the result of this, not to mention the formation of rust. Lastly, I have seen crystallization occur in the carburetor of my edger. I had to disassemble it and scrape out all of the crystallization. Ethanol is the bane of small engines!
 
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Okay, using the numbers from the Gasoline vs Ethanol chart that was posted above, here are the numbers:

Gasoline (summer blend) ....... 114,500 BTU/gal*
Ethanol Blend (E10) .................. 111,836 BTU/gal

*I even used the summer blend, which has even more energy than base gasoline.

114,500 / 111,836 = 1.024 = 2.4%

So gasoline has 2.4% more energy than E10 Blend gasoline (gasohol).

NOT SO FAST!!!

A typical internal combustion engine is 20% to 35% efficient.
That means, at best, only about a third of the gasoline's energy is converted to mechanical energy, the rest is given off as heat blown out the tailpipe and radiated from the engine.

I'll be kind and assume the VN900 is 30% efficient.

2.4% x 0.3 = 0.72%

So you can expect about a 0.72% increase in power and gas mileage.

Therefore, if you normally get 48 MPG, you can expect a whopping 48.35 MPG which is probably smaller than the accuracy of your measurements.

I guess you can also expect a 0.72% increase in power as well ....

48 HP is now 48.35 HP
58.2 ft-lbs is now 58.6 ft-lbs

... none of which you will never feel.

So, in summary, switching from E10 gasohol to 100% gasoline will yield an insignificant improvement in mileage and performance.

But there are other benefits....

Ethanol requires more energy to produce than gasoline and it takes away from the food supply (corn). Unlike gasoline, ethanol is hygroscopic meaning that it readily absorbs water from the air. If is able to absorb enough moisture, it can cause a phase separation to both ethanol and water. Water is heavier than gasoline or ethanol and it will sit on the bottom of your tank should this occur. Poor starting or no starting can be the result of this, not to mention the formation of rust. Lastly, I have seen crystallization occur in the carburetor of my edger. I had to disassemble it and scrape out all of the crystallization. Ethanol is the bane of small engines!
Wow, that's a lot of math this early in the morning, but interesting.
 

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2.4% x 0.3 = 0.72%

So you can expect about a 0.72% increase in power and gas mileage.

Therefore, if you normally get 48 MPG, you can expect a whopping 48.35 MPG which is probably smaller than the accuracy of your measurements.
You can't take the percentage difference between the two engines and then multiply it by the engine efficiency. The engine efficiency should be multiplied directly into the BTU numbers of each fuel first to see how much energy the engine can get from each fuel. Then when you divide one into the other, they would cancel each other out.

So the difference in fuel economy is about 2.4%, as you previously stated (which is consistent with the ~3% change in fuel economy according to the EPA).
 

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You can't take the percentage difference between the two engines and then multiply it by the engine efficiency. The engine efficiency should be multiplied directly into the BTU numbers of each fuel first to see how much energy the engine can get from each fuel. Then when you divide one into the other, they would cancel each other out.
Oh, but I can!

We are only talking about one engine here.

100% gasoline has roughly 3% more energy than the E10. We all agree on that. The engine can only convert 1/3 of that 3% into mechanical (useful) energy. So I stand by my original analysis which also happens to match my actual experience.

Cheers!
 

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Oh, but I can!

We are only talking about one engine here.

100% gasoline has roughly 3% more energy than the E10. We all agree on that. The engine can only convert 1/3 of that 3% into mechanical (useful) energy. So I stand by my original analysis which also happens to match my actual experience.

Cheers!
An engine using pure gasoline (114,500 BTU/gal), and 30% efficiency, means that the engine can get only 34,350 BTU/gal from the fuel as useful energy.
That same engine using 10% ethanol (111,836 BTU/gal), and 30% efficiency, means that the engine can get only That is an increase of 2.4% when using pure gasoline.

The engine efficiency percentage is not applied to the difference in energy, it is applied directly to the energies in each of the fuels.
 

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I stand corrected.
 

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Tourer I have found I get approximately 2-4 mpg better when running non ethanol fuel. After having a lot of issues with ethanol fuel in small engines I only run non ethanol in them and the motorcycle feeling it is cheep precaution.
Where to get non ethanol gas ???
 
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