The plan

[cywelchjr]

btw, I could also be completely wrong...after all I'm not a chemist or an expert by any means...this is just what i was taught in high school chemistry a little over 10 years ago...and a little help from our friend mr google...

Not sure where you got your google links, but it doesn't match either what I was taught in auto shop or in chemistry (mine was a few years before yours, OR what I find on google).

Here are a few links.

http://www.state.mn.us/mn/externalDo...ctaneFacts.pdf

http://www.edmunds.com/fuel-economy/...d-premium.html

http://www.straightdope.com/columns/...nd-regular-gas

[WMarshy]

Simply put, octane relates to the flash point of the fuel. It has nothing to do with energy content or burn temperature of the fuel. Using a higher octane in an engine that doesn't have either variable timing or a compression ratio suited for that high of a fuel grade is a waste. The combustion of the fuel will be less efficient.

[g15usmc]

Not sure where you got your google links, but it doesn't match either what I was taught in auto shop or in chemistry (mine was a few years before yours, OR what I find on google).

Here are a few links.

http://www.state.mn.us/mn/externalDo...ctaneFacts.pdf

http://www.edmunds.com/fuel-economy/...d-premium.html

http://www.straightdope.com/columns/...nd-regular-gas

As quoted from http://www.state.mn.us/mn/externalDo...ctaneFacts.pdf "Octane is a measure of a fuel’s tendency to knock or ping when it is mixed with air and burned in the cylinder of an engine. This octane rating is not based on the amount of chemical octane in the gasoline. The rating is called octane because the gasoline’s ability to prevent engine knock has been rated against the performance of pure hydrocarbon octane, which has a rating of 100. Gasoline, which is made from a blend of many other hydrocarbons, may have a higher or lower rating, depending on how its anti-knock performance compares to the performance of pure hydrocarbon octane" as quoted from me..."and i can possitively say that the octane rating is not relative to the energy content of the fuel, an octane ratings is better described as anti-knock rating since that is the pupose of it anyway...if you run a higher octane fuel you reduce the knock in the engine which will increase its efficiency, not to say that at some point its not going to help any more or that it wont hurt the fuel mileage that you get, but based on the fact that the octane is based on its Anti-knock properties we could only conclude that the higher octane can only be better for your engine" did i state something wrong in this?...

Simply put, octane relates to the flash point of the fuel. It has nothing to do with energy content or burn temperature of the fuel. Using a higher octane in an engine that doesn't have either variable timing or a compression ratio suited for that high of a fuel grade is a waste. The combustion of the fuel will be less efficient.

i agree 100% marshy...
as i stated "i can possitively say that the octane rating is not relative to the energy content of the fuel, an octane ratings is better described as anti-knock rating since that is the pupose of it anyway"

[jwhughes3]

its official!

gas octane threads are now in the same category of Hot Button topics as which oil is best, which tire is best, and what's better: Special or Standard

Everybody knows the BEST gas is the one YOU decide to put in your tank.

John

Now do I need to bring Mr King into this discussion?

[g15usmc]

gas octane threads are now in the same category of Hot Button topics as which oil is best, which tire is best, and what's better: Special or Standard

Everybody knows the BEST gas is the one YOU decide to put in your tank.

John

Now do I need to bring Mr King into this discussion?

john, tiz true...

CY, it just occured to me that i think we are saying the same thing...so heres what i think u are saying...the higher the octane the slower it is to combust therefore the higher the temperature must be to put the fuel at a point where it will combust therefore running your vehicle motor at a higher temperature...the fuel itself does not burn hotter, however it does take a higher temperature to get that fuel to combust...

BINGO I GOT IT I THINK...Dont i?

[natemoen]

gas octane threads are now in the same category of Hot Button topics as which oil is best, which tire is best, and what's better: Special or Standard

Everybody knows the BEST gas is the one YOU decide to put in your tank.

John

Now do I need to bring Mr King into this discussion?

Yup.........

[SFerinTEXAS]

Everybody knows the BEST gas is the one YOU decide to put in your tank.

Trying to quiet a disagreement is often a good idea . But not when it lets ignorance feel justified.

Hi performance engines don't get their power from hi octane fuel but from the components and design of the engine. Using it when not designed to require it will not produce more power, just waste money and fuel.

http://www.ftc.gov/bcp/edu/pubs/cons...tos/aut12.shtm

[g15usmc]

Trying to quiet a disagreement is often a good idea . But not when it lets ignorance feel justified.

Hi performance engines don't get their power from hi octane fuel but from the components and design of the engine. Using it when not designed to require it will not produce more power, just waste money and fuel.

http://www.ftc.gov/bcp/edu/pubs/cons...tos/aut12.shtm

After reading Sferin, i have come to the conclusion that i have been mostly right all along...here is my reasoning...first i already knew that the octane was based on anti-knock qualities, i knew that the fuel burns at a lower temperature as the octane lvl goes up, "High octane burns cooler and slower (keeping NOx low)"...however, and this is where i'm not completely correct, "but it also produces less power which your engine might not be ready for"
and the reason i say not completely correct is because using all of my vehicles a truck, van, camaro, 2 motorcycles as well as 2 four wheelers, i had deduced that most vehicles would also increase power and fuel economy as did mine...which is not the case...and i gather that the reason that all of mine do is because all but one of them are built around performance with high compression ratios...like my 2 quads are both built for racing, my bikes are built for high performance, my truck has a high compression ratio, though it still recommends low octane which i do use most of the time until i'm hauling my trailer in which case it is running harder and the higher octane actually helps me improve my mileage, though i often times still tow with the low octane fuel - cause its cheaper - but i know it improves the mileage because i've used both on cross country trips hauling the same load both ways both with oil changes before hand and after with the higher octane i got 13 mpg and 10 mpg with the low octane...which is the average over 2800 mile drives...and my van is on the older side of things and therefore the higher octane helps smooth the engine out which in turn improves my fuel mileage in that, and of course my camaro is also high performance...so i'd like to apologize again if anyone was offended by my ramblings...but i do it to learn and i find it amusing...

[g15usmc]

thanx to all of you for clearing it all up for me...

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[cywelchjr]

john, tiz true...

CY, it just occured to me that i think we are saying the same thing...so heres what i think u are saying...the higher the octane the slower it is to combust therefore the higher the temperature must be to put the fuel at a point where it will combust therefore running your vehicle motor at a higher temperature...the fuel itself does not burn hotter, however it does take a higher temperature to get that fuel to combust...

BINGO I GOT IT I THINK...Dont i?

Slight reword, since it burns slower, it takes longer to burn, exposing the internal parts to the flame front for a longer time period. This is not as much an issue for a water cooled engine, but for an air cooled engine which may be on the edge of overheating in come conditions already, it can be the difference between melting a piston and just making it home under the line. I'm not going to subject MY engine to the additional heat when it's NOT going to give you more power unless you have increased the compression of the engine enough to require it. BTW, while these bikes say 91 octane, that was based on a different formula than is used now, and what is called 87 octane now is typically right about what they were talking about back then as 91 octane.

[cywelchjr]

I'll also mention, my Camaro (when it was running) got better mileage on mid grade or premium, but only marginally, and not enough to justify the extra cost, it still ended up costing more per mile to run premium than to run regular. But that is because the knock sensor allows it's high compression engine to adjust to the fuel. Some modern bikes can do this as well, and some of them require mid grade or premium gas and if they do, you need to run that.

Just remember, the higher octane fuel does NOT run cleaner, so, don't just go on you getting a couple MPG better, check your $ per mile, cause unless the higher grade LOWERS it, you ARE wasting your money if the vehicle doesn't require the higher grade gas, in addition, the higher temps the engine will run because of the longer time the flame front exists in the cylinders will also lower engine life by increasing stress on the internal parts.

So yes as you said, the premium fuel may burn slightly cooler (and it it's just slightly cooler) but it does so longer, and so it actually generates more heat because of this. And unless the vehicle can take advantage of being able to advance its timing so it's not throwing unburnt fuel out the exhaust, at best mileage will stay the same, at worst it will go down (my XS11 goes down on premium significantly and just slightly on mid grade). As a matter of fact, if I switch to mid grade or premium fuel, I have to turn my idle speed up because it slows down by about 50-100 RPM. Now of course Ca gas is crap anyways, so that makes it FAR worse, so real gas is likely not as bad (as a matter of fact I don't recall things being as touchy back in the day), but I've gotta live with what I gotta live with.

[g15usmc]

Slight reword, since it burns slower, it takes longer to burn, exposing the internal parts to the flame front for a longer time period. This is not as much an issue for a water cooled engine, but for an air cooled engine which may be on the edge of overheating in come conditions already, it can be the difference between melting a piston and just making it home under the line. I'm not going to subject MY engine to the additional heat when it's NOT going to give you more power unless you have increased the compression of the engine enough to require it. BTW, while these bikes say 91 octane, that was based on a different formula than is used now, and what is called 87 octane now is typically right about what they were talking about back then as 91 octane.

I'll also mention, my Camaro (when it was running) got better mileage on mid grade or premium, but only marginally, and not enough to justify the extra cost, it still ended up costing more per mile to run premium than to run regular. But that is because the knock sensor allows it's high compression engine to adjust to the fuel. Some modern bikes can do this as well, and some of them require mid grade or premium gas and if they do, you need to run that.

Just remember, the higher octane fuel does NOT run cleaner, so, don't just go on you getting a couple MPG better, check your $ per mile, cause unless the higher grade LOWERS it, you ARE wasting your money if the vehicle doesn't require the higher grade gas, in addition, the higher temps the engine will run because of the longer time the flame front exists in the cylinders will also lower engine life by increasing stress on the internal parts.

So yes as you said, the premium fuel may burn slightly cooler (and it it's just slightly cooler) but it does so longer, and so it actually generates more heat because of this. And unless the vehicle can take advantage of being able to advance its timing so it's not throwing unburnt fuel out the exhaust, at best mileage will stay the same, at worst it will go down (my XS11 goes down on premium significantly and just slightly on mid grade). As a matter of fact, if I switch to mid grade or premium fuel, I have to turn my idle speed up because it slows down by about 50-100 RPM. Now of course Ca gas is crap anyways, so that makes it FAR worse, so real gas is likely not as bad (as a matter of fact I don't recall things being as touchy back in the day), but I've gotta live with what I gotta live with.

Good deal!...i've only tryed 87 in the xs before the rebuild...and it didn't like it, but since then maybe things are better...it also might have been my nasty gummed up carbs from the previous owner...but i was just testing to get bike running...after i traded my dining room table for it...and yes of course it went in my dining room...

[planedick]

Hijacked thread

The Plan was originally about planning for a long trip. Nothing about what gas to use.... As for what gas, just remember these engines were designed for regular gas. That's what I use, it serves me and the bike well. You will be hard pressed to find one that runs better than mine. 'Nuff said.

[natemoen]

The Plan was originally about planning for a long trip. Nothing about what gas to use.... As for what gas, just remember these engines were designed for regular gas. That's what I use, it serves me and the bike well. You will be hard pressed to find one that runs better than mine. 'Nuff said.

Glad your bike runs well! Hope you get to do your trip at some point! Good luck and hope things are going well for you!

[bikerphil]

Only one thing worse than an oil thread is a gas thread.