Quote from: Gunslinger on March 02, 2012, 11:30:57 AM
Nothing but 93. Saying regular is better than premium...this is based off of what?
I don't care about saving less than a dollar per tank.

it's based on science.
higher octane burns slower than lower octane.
putting 93 in an engine designed and tuned for 87 effectively retards the timing
more unburned fuel comes out in the exhaust, hurting mileage, power, and emissions.

you can go ahead and spend your extra $.70 per tank for worse performance... i'll save money AND have a better running bike.

My owner's manual states that the bike "requires regular unleaded gasoline with a minimum pump octane rating of 87((R+M)/2 method)." YMMV but I have found that the bike runs better and I get better mileage from higher octane. Higher price with higher mileage vs. lower price and lower mileage, cost wise it probably works out about even. BTW it will run fine on 87. Use what makes you feel good

I always use 91 in anything but a car or truck, I dont have a lot of experience in bikes but in sleds and atvs if you use 87 you always have problems with the gas because it has ethenal in it. I was told by a reputable mechanic that that you should run a tank of 91 octane once or twice a year in any car with fuel injection. this came about because my wife's car had her check engine light come on and i took in to the dealer. (her car is a 2008 pont G6 with under 55,000 miles.) they said that one of the injectors was wasnt spaying wright that it might be plugged some what, so they wanted to run a fuel treatment through it. I asked how much it costs, they said $200. I asked what it was, they said that they would plug the injectors in to a machine that had a cleaning solution in it and run the car for about 10-15 minutes and it would clean of the injectors. i asked what is the difference of me putting premium gas in the car with a can of seafoam. he said that it was about the same thing. so thats what i did and the light went off. it was after this that i asked my friend who told me to do the one tank of 91 octane a year, because gas with ethenal doesnt burn as clean as gas without it. Just what i have been told, take it or leave it.

i know the gs isn't FI but either is my atv or sled, and it always seems to run better.

Quotehigher octane burns slower than lower octane.

Thats not accurate.

Octane rating, as we know it is nothing more than this: A fuel's resistance to ignition through compression. Higher octane fuels cost more because we are not allowed to add lead compounds like T-E lead to gas anymore, and lead substitutes are not cheap.

When octane boosters are added to fuel they literally change mixture makeup of the fuel, displacing more easily ignited HCs.

Hydrocarbons in low octane fuels have many weakly bonded hydrogens These are the ones that combine quickly and easily with oxygen and produce fire when heat is added, even just heat of compression.

High octane fuel has fewer loose hydrogens, and is harder to ignite. It burns just as fast as regular fuel. Its not like diesel fuel.

Quote(high octane fuel) effectively retards the timing

This isn't true at all. All the fuel ignites when the spark plug fires. Thats what its there for.

Quotebike runs better and I get better mileage from higher octane.

This is questionable.

Higher octane fuel was created to appease the higher compression engine. Not the other way around. Because higher compression engines produce more power by increasing fuel temp before combustion, which leads to a more complete burn, we needed a fuel that would not ignite before it was supposed to. (knocking) Higher octane fuel actually contains LESS useful hydrocarbons per unit than regular. Thats just the way it is. It may burn smoother (more controlled burn), which is the meaning of the rating, but not with more energy.

Our engines may not burn high test as efficiently because they don't create enough preignition heat to effectively loosen the bonds in the tighter hydrocarbons composing that type of fuel. (Additional Heat = catalyst for reaction with oxygen.)
That doesn't mean that high test will give you worse mileage, you will use fuel at the same rate, your jets and intake will not have changed - That is what determines your fuel usage. (and your wrist.)

I dont know the vapor pressure differences between the grades of gasoline, maybe better fuel milage could be a product of the vapor pressure of high test being lower, thus, it atomizes less readily, and your carb uses less of it by default. I'll do some more research if anyone cares.

im learning new stuff! by all means , keep researching.

I did a bit more research as a result of this thread.

http://e85vehicles.com/e85/index.php?topic=1893.0

http://speedtalk.com/forum/viewtopic.php?p=84096&sid=a573a6000ba297a30a99964c0a32efb8

Short version is that flame propagation speed has no relationship with octane rating - different mixtures will have different flame front speeds - sometimes the low octane will burn quicker, other times the high test will burn quicker. One of the links above compares the flame speed of ethanol to normal pump gas, and shows that the flame speed of ethanol is much faster than gas despite the higher octane rating. My previous comments about flame propagation speed were made in error.

Regarding a post above: you're likely to have more ethanol in a high octane gasoline than a low octane gasoline. Ethanol has a very high octane rating, and will tend to improve the rating of the gasoline it's added to. It did after all, replace MTBE as a common octane enhancer.

You're right burning1, ethanol is a pretty common octane enhancer, which kinda blows for people trying to get away from it.


Lower grade gasoline, with all its sensitive HCs tends to explode more than burn even at standard pressure, and that erratic nature does slow down the flame propagation because the looser hydros ignite first. Expansion pushes everything around, and then you have to play flame-a-chase trying to ignite more stubborn molecules.
Premium grades will have a more uniform mixture and burn radially and evenly from the ignition point.

There is no standardization on the mixture of gasoline that makes up a given octane level, but there are mixtures that are expected to work. Samples are taken pretty randomly, I believe, to test octane rating. If at all. I imagine the batch of hydrocarbons varies in every truckload delivered to the gas station.

This ads another problem to the knocking issue - the L/O gas is also not burning the way the crown/head interaction wants it to. And ignition may be completely in the wrong location in the cylinder when it pre-ignites.

Actually, the wikipedia article has two HC structures next to each other with respective ratings, and if you guys like chemistry, you can see why they are rated differently.

Theoretically speaking, you could get better gas mileage with higher octane IF it enhanced the performance of the engine.

Consider that, as Funderb said, the fuel consumption is determined by two factors: percentage of throttle and size of jets. The relationship between the jets and throttle percentage is fixed.

Now, consider this: fuel efficiency is not the same thing as "MPG" yet they go hand in hand - why? The efficiency of the motor to produce power via burning gasoline is what determines the mpg when all other factors are static.

For real world examples...let's use a car that has cruise control. You're traveling on the interstate, trying to go up an incline, with the car set at 75mph. If you're generating 10 extra horsepower from better fuel, the car will more easily climb that hill, and thus increase your fuel mileage.

Of course, all of the above is just speculation and there are other factors to consider. Like the fact that better octane fuel does not equate to more power like so many people believe.

So I was fiddling with "adversary" earlier and had the seat off. The is a sticker on the finder that say to use the low end octane. Also what oil to use and so one.


---
I am here: http://tapatalk.com/map.php?e0n1le

I have a friend that still thinks Premium is just better gas, regardless of what I tell him.
Just a FYI...Costco claims 5X the EPA requirement  for detergent in their gas.

http://shop.costco.com/BC/In-The-Warehouse/Gasoline.aspx

The truth is that 87 octane, or whatever the minimum is in your area, is going to be much fresher than the premium or mid-grade. The reason for this is because it's what the majority of people put in their vehicles.

Wanna fight about it?

Out back behind the sheds?

Put some kero in it, a spoon full of avgas per tank, whatever... the GS500 doesn't really care - BUT - don't put in ethanol fuel. If regular makes you all warm and fuzzy, use it. If the next up gives you a bone, use that. If top of the line sizzles your schnitzel then hook in, just use whatever you want that does not have ethanol in it.

Michael

Quote from: mister on March 03, 2012, 02:07:49 PM
Wanna fight about it?

Out back behind the sheds?

Put some kero in it, a spoon full of avgas per tank, whatever... the GS500 doesn't really care - BUT - don't put in ethanol fuel. If regular makes you all warm and fuzzy, use it. If the next up gives you a bone, use that. If top of the line sizzles your schnitzel then hook in, just use whatever you want that does not have ethanol in it.

Michael

Well, here in the states...most of us are forced to use ethanol-laced fuel. Most of the pumps here in Georgia have a "up to 10% ethanol" warning.

Quote from: Kijona on March 03, 2012, 02:17:06 PM

Quote from: mister on March 03, 2012, 02:07:49 PM
Wanna fight about it?

Out back behind the sheds?

Put some kero in it, a spoon full of avgas per tank, whatever... the GS500 doesn't really care - BUT - don't put in ethanol fuel. If regular makes you all warm and fuzzy, use it. If the next up gives you a bone, use that. If top of the line sizzles your schnitzel then hook in, just use whatever you want that does not have ethanol in it.

Michael

Well, here in the states...most of us are forced to use ethanol-laced fuel. Most of the pumps here in Georgia have a "up to 10% ethanol" warning.

MOST but not all, right? So go use the one without the ethanol.

Michael

Mister, here in the states finding ethanol free fuel is like finding a needle in a stack of needles.
In fl, its ~15% ethanol. Its politics.

There are FEW filling stations that offer ethanol free gas. And of those few, a lot of them are simply lying to attract the marine crowd and the occasional cyclist.


The best we can do is use sta-bil or the like for long term storage and buy ethanol resistant rubbers.

I think all the stations I've seen around here have ethanol at 10 to 15% concentrations.  My owners manual says never, under any circumstances to use fuel with more than 5% methanol (wood alcohol), but ethanol is ok up to a 10% solution.

Quote from: mister on March 03, 2012, 02:25:04 PM

Quote from: Kijona on March 03, 2012, 02:17:06 PM

Quote from: mister on March 03, 2012, 02:07:49 PM
Wanna fight about it?

Out back behind the sheds?

Put some kero in it, a spoon full of avgas per tank, whatever... the GS500 doesn't really care - BUT - don't put in ethanol fuel. If regular makes you all warm and fuzzy, use it. If the next up gives you a bone, use that. If top of the line sizzles your schnitzel then hook in, just use whatever you want that does not have ethanol in it.

Michael

Well, here in the states...most of us are forced to use ethanol-laced fuel. Most of the pumps here in Georgia have a "up to 10% ethanol" warning.

MOST but not all, right? So go use the one without the ethanol.

Michael

I said most because I'm sure there are some somewhere that have pure gas. However, I live in Atlanta, and here, ethanol free gas is a thing of the past. Sure, I could probably find one somewhere out in the boonies but I'm not putting hundreds of miles on my bike just to get ethanol free gas.

Having worked at a gas station while i was going to college the first time (1st time law enforcement, 2nd Millwright) usually the tanks that they put fuel in are different sizes, they don't just have a 5,000 gallon tank for each  type of fuel: reg, prem, plus and diesel. (at least most don't) it will vary by the store some what because at least in new stores they will look at the area and see what the demand will be. also prem 91 at least in Minnesota is the most likely to not have ethanol in it or the least percent in it. that's the only reason i use it.

Quote from: J_Walker on March 01, 2012, 03:30:09 PM
Only problem with gas now days, is that the ethanol thats in it... Good lord. We pay almost $4.00 a gallon yet its alright to them to put 15%+ ethanol in our gas... And the ethanol destroys engines over time.

Not to start anything. but did you know almost 80% of our gas that we use in the states actually comes from THE STATES. the 20% is imported.. so what does that tell you? That the "war in the middle east" is a bunch of BS on gas prices.. And it's just giving them a reason to raise the prices. Just my 2 cents

I swear I don't know where you get your information.  We import almost 60% of our petroleum.  A large portion does come from North America, but not from the U.S., mostly from Canada and Mexico.  (And the reason we purchase from them is due to Tariffs and NAFTA regulations.)

You also have to remember that oil is a finite resource, and it will eventually run out in both Canada and Mexico, leaving us desperate for the oil in the middle east (which, we assume, because no one knows for sure, is a vastly larger supply than our own). 

Read up:

http://www.consumerenergyreport.com/research/crude-oil/where-the-us-gets-its-oil-from/

http://www.eia.gov/pub/oil_gas/petroleum/data_publications/company_level_imports/current/import.html

Quote from: shonole on March 04, 2012, 01:47:18 AM

Quote from: J_Walker on March 01, 2012, 03:30:09 PM
Only problem with gas now days, is that the ethanol thats in it... Good lord. We pay almost $4.00 a gallon yet its alright to them to put 15%+ ethanol in our gas... And the ethanol destroys engines over time.

Not to start anything. but did you know almost 80% of our gas that we use in the states actually comes from THE STATES. the 20% is imported.. so what does that tell you? That the "war in the middle east" is a bunch of BS on gas prices.. And it's just giving them a reason to raise the prices. Just my 2 cents

I swear I don't know where you get your information.  We import almost 60% of our petroleum.  A large portion does come from North America, but not from the U.S., mostly from Canada and Mexico.  (And the reason we purchase from them is due to Tariffs and NAFTA regulations.)

You also have to remember that oil is a finite resource, and it will eventually run out in both Canada and Mexico, leaving us desperate for the oil in the middle east (which, we assume, because no one knows for sure, is a vastly larger supply than our own). 

Read up:

http://www.consumerenergyreport.com/research/crude-oil/where-the-us-gets-its-oil-from/

http://www.eia.gov/pub/oil_gas/petroleum/data_publications/company_level_imports/current/import.html

We won't run out.

When a well starts to lose pressure (oil is emptying) it is rested. Miraculously it fills back up again. SOME kind of reaction is going on deep Deep DEEP down that creates oil. Oil is not the rotting bodies of dinosaurs and trees.

Besides, Australia has so many capped oil wells it is not funny. I know people who have been drilling for, finding and capping oil wells in this country and offshore within our waters, for decades. We have Loads of oil. Why use your own when you can use someone else's and keep yours in reserve just in case?

Michael