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better mpg..or myth

For what its worth, when I was a wee teenager working for a 76, the owner told me that the Peremium was actually intedned for high Performance cars (hi RPM etc) and that the oil companies and station owners were getting rich by misleading the average joe to believe Premium would improve your MPG and help your motor run better and longer. I had one of the few honest gas station bosses in town at the time, I queried the other two stations in town and was told the "Premium is better" lie.
 
I have tried high and low octane fuel in my heritage 103 and have to say I can see no measureable difference. I normally try to use 91 or better as I have 10.5:1 compression but it does not ping when I use 88.
I believe that if you buy premium gas thinking you get better economy you are throwing your money away. If you have compression higher than 10.5:1 it might not like 88 octane fuel. This is just my opinion yours may vary.
 
JDPEagle said:
Complete Myth.... ditch the ethanol and you'll get better mileage and a longer running bike. Thanks EPA.



This is also a myth (although the oil companies would want you to think otherwise). The octane rating simply indicates the pressure the fuel can withstand before spontaneously igniting. For better "performance," one should always use the lowest octane possible which results in no "knocking" (or fuel ignition without a spark). The lower the octane rating, the lower the pressure the fuel can withstand without igniting. Higher performing engines often run at higher compression ratios thereby making a higher octane necessary; however, the fuel is not the source of the performance... the engine is.

All that being said; follow your owner's manual.
Click to expand...

+1 No relationship between octane and mileage.
 
drbillk said:
+1 No relationship between octane and mileage.
Click to expand...


There sure is a relationship.

Consider it this way. When an engine manufacturer designs an engine and recommends a minimum octane rating to be used in that engine and an owner decides that he knows more than the manufacturer of that engine and uses a lower grade or octane fuel, the engine management of that engine will and does retard ignition timing to eliminate knock/ping and detonation to prevent engine damage. In doing this it will reduce the output of that engine which in turn will lower mileage or MPG.

Like it or not this is the end result of using a lower than recommended octane in any engine. You may also notice that the performance of the engine isn't there as it was with the higher octane. While it is possible to "detune" an engine to run on a lower octane than recommended, the engine will usually run hotter and in most cases feel like it is lacking in the power department a noticable amount.

There's many differing views on running a lower octane and "Bubba" said it's OK and will run just as good as the 93 octane but anyone that is mechanically inclined at the very least can realize that the timing that is withdrawn from the engine by the engine management system when running a lower grade of fuel can and will effect MPG.
 
Wow! learned a lot,thankyou everybody,and its very gratifying to know that my glide will run /has always run excellently on fuel with a 93 octane rating,specially as in this neck of the woods leastways,there are only 3 ratings available at the pumps,..93..95..and diesel!
 
I have found that if you buy your fuel from any station that has a truck filling up their underground tanks often you will be buying fresher fuel. A station that doesn't need to be restocked as often will have fuel that is not as fresh. I buy my fuel from a local station thhat stays busy and restocks it's underground tank frequently, and I do not have any issues using that gas. I have bought gas at other stations and have experienced poor quality fuel issues. I very seldom buy any fuel at any other stops unless I have no other option to get back to my local station. Where I live 91 octane is the highest grade available...
Remember, Ride Safe...
 
Actually not as much age as doing their homework early...THAT is timeless...ahh the late 60''s were my initial years in automotive with motorcycles following soon after, gas powered engines just made the world go around...they say 1898 was the year gasoline engine and bicycle was combined together for the first time...our love affair with two wheel sports began with our fore-fathers and daughters caught on way early on. No Myth...just Reality with a long time line! :hii
 
Most, if not all, manufactors overstate compression ratio. Then say use this octane for the engine. Oversafe on compression/octane rating, so way less warrenty complaints.
They, as you and I know, as engine ages octane needs go up, but 99.99% of time, out of warrenty.
wilks3
:USA
 
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