So I traded bikes with my roomate for the day about two weeks ago under the promise that we would fill each others bike up. (He rides an '07 ZX6R) not knowing my bike takes 87, he put 91 like his bike uses. He tells me this and I'm like no biggie, I'll just fill it up with 87 next time.
When I ride my bike though, it feels great very responsive and torquey, especially on the highway. I decided to try one more full tank of 91 just to see how it goes. Bike has felt very good with only me having to use slightly more choke upon starting it up but I'm still using no choke in less than a minute, usually before I'm even geared up and ready to ride. Now today I filled it up with 87 and figured my gas mileage when using 91. It was 56.6mpg, about 2mpg better than I usually get using 87.
This really suprised me. I expected it to be around 52-53ish since I've actually been riding my bike a bit harder. Now it has been very hot here in OK, 95-100+*F everyday, and I hear higher octane is better for hotter weather.
Now two questions. . .
Has anybody else experienced this?
What do I risk by continuing to run 91?
Bike is an '09 with 5800 mi.
you mostly risk spending more money on gas ;)
Over the past few months I also experienced increase in my mileage. I keep refuelling at the same 2 stations and I always buy 87... I can't precisely explain the increase. I GUESS:
- better carb synchronization
- gentler driving
- less choke for start ups
In other words I don't think you should assume that your mileage increased just yet. If it is consistent for few more fuel ups then maybe. Right now I would be very skeptical about it.
I just filled up Suki with 91 too and noticed that shes not quite as cold blooded, running alittle smoother and is withstanding the heat alittle better. im an automotive mech so my training all wants to scream :bs: but my gut, my butt, and previous experience tell me that occacionally it does make a difference. higher octane fuel burns slower and and slightly cooler. so it may be bandaiding my tight valves, lean running, and unbalanced Suki. :thumb: soooooo..... there no clear cut answer but ill see how she performs on and off with i fix these problems one by one.
IMHO opinion, i have found fuel economy impacted more by environmental factors than by octane ratings. With more than 42,000 miles in the last 3.5 years (and I have tracked MPG on EVERY tank of gas I've put into my '07), I find air temperature to be the most influential factor (outside of a heavy throttle hand).
I consistently average about 56-58 in the winter and 62-64 in the summer. Why? Two factors: 1) Warmup time. I don't think I need to discuss this. 2) Air density: this means drag. Winter air is heavier, drier and more dense than summer air. The warmer the air, the more moisture it can hold, and moisture (H20) weighs less than the O2 it replaces, making the air lighter and less dense. This means less drag in the summer air and better gas mileage. It's no coincidence my best gas mileage occurs during the hottest part of the year!
My $0.02
Quote from: MVent03 on August 27, 2011, 11:08:23 AM
So I traded bikes with my roomate for the day about two weeks ago under the promise that we would fill each others bike up. (He rides an '07 ZX6R) not knowing my bike takes 87, he put 91 like his bike uses. He tells me this and I'm like no biggie, I'll just fill it up with 87 next time.
When I ride my bike though, it feels great very responsive and torquey, especially on the highway. I decided to try one more full tank of 91 just to see how it goes. Bike has felt very good with only me having to use slightly more choke upon starting it up but I'm still using no choke in less than a minute, usually before I'm even geared up and ready to ride. Now today I filled it up with 87 and figured my gas mileage when using 91. It was 56.6mpg, about 2mpg better than I usually get using 87.
This really suprised me. I expected it to be around 52-53ish since I've actually been riding my bike a bit harder. Now it has been very hot here in OK, 95-100+*F everyday, and I hear higher octane is better for hotter weather.
Now two questions. . .
Has anybody else experienced this?
What do I risk by continuing to run 91?
Bike is an '09 with 5800 mi.
There is a thread on oil.......same applies for octane, or gas brand...
Search the internet and find about all the myths.........
People will swear on their mother about the benefits of higher octane...but without proof....the only way to prove any of the claims would be with a "Blind taste test"........that is have many riders test out bikes without knowing what gas was in them, then even telling them they had high octane when they didn't as a "control".......of course the many many variables would all have to be controlled.
"feel"..."perfromance"......mileage....are based on so many factors.....like temperature, humidity, driving style, etc..
Higher octane won't hurt the machine.....it's all about getting the money out of your wallet and into somebody elses.
Cookie
I was gonna say "don't tell Cookie :whisper:" but... too late :icon_mrgreen:
Yes, generally speaking, you are far more likely to get a change in mileage due to other things besides Octane, on a GS500 - octane is NOT an Energy Rating but rather an Anti Knock rating (higher compression engines have a tendency to autodetonate like a Diesel engine, so this tendency is reduced by having gas with high antiknock, higher octane).
However, *I* found the lower octane from one particular brand gives poorer performance.
Where we are there are two refineries - BP and Caltex (and they have a supply pipe linking to each other's refinery so if one is low on raw crude they can get some from the other when a ship comes in). All fuel in our area comes from either those two, regardless of the Brand. Where we are, 7/11 gas Stations get their fuel from Shell. Shell has no refinery, they are just a tank farm and commission Caltex to create fuel according to Their (Shell's) specs.
*I* have found, using the lower Octane from 7/11 (Shell) I get less mileage. BUT, using the lower, mid or high octane from BP I get the same mileage. The bike also Sounds better - sounds like it is running better - on the BP. So for me, the brand made a difference. My car also runs poorer on Shell than BP. Something in the Shell mix doesn't agree with my two Suzukis.
Barring that, like I said, there is no Difference in performance between the various BP octane fuels.
OH... one thing I was told by Caltex is, they have an additive in their higher octane (higher than standard) to help keep fuel injectors clean. I could surmise that some performance change Might be seen as a result of such an additive keeping the jets cleaner. But that's only a theory.
Michael
Quote from: mister on August 27, 2011, 12:54:32 PM
I was gonna say "don't tell Cookie :whisper:" but... too late :icon_mrgreen:
Yes, generally speaking, you are far more likely to get a change in mileage due to other things besides Octane, on a GS500 - octane is NOT an Energy Rating but rather an Anti Knock rating (higher compression engines have a tendency to autodetonate like a Diesel engine, so this tendency is reduced by having gas with high antiknock, higher octane).
However, *I* found the lower octane from one particular brand gives poorer performance.
Where we are there are two refineries - BP and Caltex (and they have a supply pipe linking to each other's refinery so if one is low on raw crude they can get some from the other when a ship comes in). All fuel in our area comes from either those two, regardless of the Brand. Where we are, 7/11 gas Stations get their fuel from Shell. Shell has no refinery, they are just a tank farm and commission Caltex to create fuel according to Their (Shell's) specs.
*I* have found, using the lower Octane from 7/11 (Shell) I get less mileage. BUT, using the lower, mid or high octane from BP I get the same mileage. The bike also Sounds better - sounds like it is running better - on the BP. So for me, the brand made a difference. My car also runs poorer on Shell than BP. Something in the Shell mix doesn't agree with my two Suzukis.
Barring that, like I said, there is no Difference in performance between the various BP octane fuels.
OH... one thing I was told by Caltex is, they have an additive in their higher octane (higher than standard) to help keep fuel injectors clean. I could surmise that some performance change Might be seen as a result of such an additive keeping the jets cleaner. But that's only a theory.
Michael
LOL.....hey...whatever makes you happy!
Just to show the variables....I use gas from the same station around the corner from my house...I always use "regular".....My mileage varies from 60 to 70 MPG.....lowest I ever got was 59 and tops was 72.........
But that represents a 16% swing due to factors other than the gas!!!
In terms of cost.....hight test is only about 2 to 3% more expensive around here...so why not go for it!?
Cookie
IIRC, don't some stations keep ethanol out of their high grade gas? A mixture of 100% gasoline will get you more power and mileage than a 90/10% mix of gas and ethanol- regardless of knock rating.
actually most company's have more ethanol in there premium then in there regular, ethanol is a octane booster... in pure form its 110 octane so if you mix it in with lower octane gas you get premium!
Quote from: Big Rich on August 27, 2011, 02:04:40 PM
IIRC, don't some stations keep ethanol out of their high grade gas? A mixture of 100% gasoline will get you more power and mileage than a 90/10% mix of gas and ethanol- regardless of knock rating.
Ethanol is a bad idea and will ruin the gas mileage......there are some staions with "pure gas" but not in my state.....
I can get 100 actane "straight" gas (with lead) where I work at the airport....lots of guys use it in Two Stroke engines....they say the ethanol gas will not run right..
But at $6.00 a gallon...I'll have to pass on that..
Cookie
I agree with you Cookie. I meant to specify that if the high octane gas the OP got was ethanol free, that would explain the power and mileage gains.
Either that, or there are some problems with pre-ignition in their engine and the anti knock qualities of high octane gas are a band aid.
To clarify, I only use 100% gasoline. No ethanol.
I was surprised when I did the math and figured my mileage. I did it twice to make sure. If I'm not going to ruin or prematurely wear anything, I'd like to continue the experiment. The difference between filling up with 87 vs. 91 is about $1.10 per tank. I think I can swing that. I'm still saving money over driving my car.
I also get my gas from Shell usually. 7-11 if I'm in need and can't find a Shell. I'm not real brand loyal, just no ethanol.
Quote from: MVent03 on August 27, 2011, 05:51:56 PM
If I'm not going to ruin or prematurely wear anything, I'd like to continue the experiment.
Go for it. If there was any damage to be expected, the European guys would mention that. I run mine with 95, sometimes 98. No problem at all (except for the costs)! :icon_mrgreen:
I always run on 98 no matter the brand but I try to stick with v power (shell) for my bike and car.
in the haynes manual 89 t0 08 models recomended minimum91 oct .I myself run 98 octane BP and average 69 to 70 mpg my bike has timing advanced large jets bigger airfilter . no trouble with starting .and more lively performance .Spark plugs have done 6000 miles and look good for another 6000 .with a compression ratio of 9.0 to 1 it is on the edge to be running anything lower than 91 octane .98 octane is cleaner burning because the lower the octane the more oil is in the fuel hence less performance .Any fuel above this would not be an advantage unless you increased the compressin ratio to take advantage of it ,and why would you want to with such a great engine.
Quote from: MVent03 on August 27, 2011, 05:51:56 PM
To clarify, I only use 100% gasoline. No ethanol.
I was surprised when I did the math and figured my mileage. I did it twice to make sure. If I'm not going to ruin or prematurely wear anything, I'd like to continue the experiment. The difference between filling up with 87 vs. 91 is about $1.10 per tank. I think I can swing that. I'm still saving money over driving my car.
I also get my gas from Shell usually. 7-11 if I'm in need and can't find a Shell. I'm not real brand loyal, just no ethanol.
Most "experts" say that entanol in gas is likely to damage motorcycle engines over time. Pure gas will not cause these damages. It has to do with water retention of ethanol.
Cookie
Quote from: twinrat on August 28, 2011, 12:46:14 AM
in the haynes manual 89 t0 08 models recomended minimum91 oct .I myself run 98 octane BP and average 69 to 70 mpg my bike has timing advanced large jets bigger airfilter . no trouble with starting .and more lively performance .Spark plugs have done 6000 miles and look good for another 6000 .with a compression ratio of 9.0 to 1 it is on the edge to be running anything lower than 91 octane .98 octane is cleaner burning because the lower the octane the more oil is in the fuel hence less performance .Any fuel above this would not be an advantage unless you increased the compressin ratio to take advantage of it ,and why would you want to with such a great engine.
Compression ratio is not the only factor to consider when talking octane required......
Old airplane engines had relatively low compression ration...but really big cylinders...lots of piston area..need high octane due to area.....motorcycles have usually small pistons...can go higher compression ratio without higher octane necessary....it all about "knock" (preignition)
I hate to start an arguement...but "cleaner burning" doesn't enter into it....
Basically if you have "knock" you need higher octane or engine modification or tuning....If you don't have "knock" you don't need higher octane. If higher octane means no ethanol, go for it...
Higher octane will yeild more power, ONLY IF the engine is designed and tuned for that.....there is no more power in the fuel....it just means the engine can be tuned to be more effecient....like higher compression, advanced timing...."stock" gs will not benefit..........
When you read the manuals...you have to be careful of which "octan rating system" is being referred to..........there are two basic systems which yield different octane rating for the same gas.....in USA they calcualte both ways and average them together to give the number you see at the pump..........
Cookie
From Wiki:
Research Octane Number (RON)The most common type of octane rating worldwide is the Research Octane Number (RON). RON is determined by running the fuel in a test engine with a variable compression ratio under controlled conditions, and comparing the results with those for mixtures of iso-octane and n-heptane.
Motor Octane Number (MON)There is another type of octane rating, called Motor Octane Number (MON), or the aviation lean octane rating, which is a better measure of how the fuel behaves when under load, as it is determined at 900 rpm engine speed, instead of the 600 rpm for RON.[2][3] MON testing uses a similar test engine to that used in RON testing, but with a preheated fuel mixture, higher engine speed, and variable ignition timing to further stress the fuel's knock resistance. Depending on the composition of the fuel, the MON of a modern gasoline will be about 8 to 10 points lower than the RON, however there is no direct link between RON and MON. Normally, fuel specifications require both a minimum RON and a minimum MON.[citation needed]
Anti-Knock Index (AKI)In most countries, including Australia and all of those in Europe, the "headline" octane rating shown on the pump is the RON, but in Canada, the United States and some other countries, like Brazil, the headline number is the average of the RON and the MON, called the Anti-Knock Index (AKI, and often written on pumps as (R+M)/2). It may also sometimes be called the Pump Octane Number (PON).
Difference between RON and AKI Because of the 8 to 10 point difference noted above, the octane rating shown in the United States is 4 to 5 points lower than the rating shown elsewhere in the world for the same fuel. See the table in the following section for a comparison.
I generally ride in places where 115 octane fuel is available. I stick to the lowest grade I can find. Pure gas is better than ethanol gas, IMO.
Quote from: twinrat on August 28, 2011, 12:46:14 AM
in the haynes manual 89 t0 08 models recomended minimum91 oct .I myself run 98 octane BP and average 69 to 70 mpg my bike has timing advanced large jets bigger airfilter . no trouble with starting .and more lively performance .Spark plugs have done 6000 miles and look good for another 6000 .with a compression ratio of 9.0 to 1 it is on the edge to be running anything lower than 91 octane .98 octane is cleaner burning because the lower the octane the more oil is in the fuel hence less performance .Any fuel above this would not be an advantage unless you increased the compressin ratio to take advantage of it ,and why would you want to with such a great engine.
Hmmm, on Flick it is plainly stated 87 minimum why is haynes different? BTW Flick hates the pricey stuff he's cheap like his owner LOL!
Mary
If you are using 91, and didn't care to get it running the best it can run, you can lean it back via jetting to indeed get better gas mileage. 91 will knock and ping at a much later stage than 87 and as such can be run leaner cos lean = detonation ... however 91 = less likely detonation ...
Cool.
Buddha.
The 98 you're filling up is probably RON octane rating. It's about the equivalent of 91 octane fuel in the states. 91 RON octane rating fuel is, based on a quick search, generally not available in the UK... But if it were, it would be about the equivalent of US 89 octane fuel (RON+MON/2) Check your manual for what rating method is specified; it's very possible that if you have a UK localized manual that it's specifying the equivalent of US Regular unleaded fuel.
What about shell v power or bp ulitmate? Both are 98 ron fuels sold in many different countries surely it's the same formulation. I mean even the F1 cars use v power. So at least v power is the same no matter where.
Quote from: aussiegs on August 31, 2011, 02:55:43 PM
What about shell v power or bp ulitmate? Both are 98 ron fuels sold in many different countries surely it's the same formulation. I mean even the F1 cars use v power. So at least v power is the same no matter where.
What's the difference between 95 kilometres and 59 miles?
MON+RON/2 and RON are different ways of rating gasoline. The same fuel will have different octane ratings on each scale, despite being the same. Generally, the mapping is 87=91, 89=95, 91=98.
My bad sorry always wondered why the US had 89 and 91. I thought it meant u guys were running a lower octane fuel than the rest of us.
All consumer-grade gasoline has the same basic ingredients in the soup, but the additives vary widely depending on where it is sold. In the US, methanol and methanol blends are used widely thoughout the midwest part of the country, but I haven't seen it here in southern California yet.
Gas is gas, but only to a point; environmental regulations in different parts of the US dictate changes to the final product, among other reasons. People in the US snow belt get a different blend during the winter than we get here, where "winter" means the temps don't usually go much higher than about ~75F, which is ~25C... They have to start COLD engines with thick oil; if the temps go much below ~45F here (~7C) during a winter night, my girlfriend wants an extra blanket on the bed...
I read somewhere, that if you use an octane rating significantly higher than what is recommended, it burns hotter, which tends to be bad for the spark plugs or something.
I dont know about gas mileage, but i do notice that the bike seems a bit smoother and happier on 93 octane here in MA.
Quote from: The Buddha on August 31, 2011, 12:05:41 PM
If you are using 91, and didn't care to get it running the best it can run, you can lean it back via jetting to indeed get better gas mileage. 91 will knock and ping at a much later stage than 87 and as such can be run leaner cos lean = detonation ... however 91 = less likely detonation ...
Cool.
Buddha.
Probably a different topic but what would you do to get it running the best it can?
Are you just referencing the timing advance and re-jetting?
So let me tell you s short story...
I am coming back home from school few days ago and I notice that my bike feels really smooth and edgy like it had a bit more power. I am thinking "this is nice" and I play with throttle a bit, speed up slow down and try to come up with a reason why it feels better.
Then I realized that I fuelled it up with Premium gas because the gas station was out of regular due to Hurricane Irene. I keep going home, flick of a wrist 2nd, 3rd gear, 70mph, I am thinking: shoot I need to slow down, and I do.
I kept enjoying the ride and then I suddenly recalled this thread about Regular vs Premium gas. I was thinking to myself that there must be something to this Premium gas myth, even though I have done a research many times and knew better.
And then I recalled one more thing... It was my car that I filled with premium and not my bike...
So what I am trying to say is that unless you can precisely measure power output and smoothness of the ride, it is safe to assume that both grades of gasoline give you the same results. It is all in our heads how we perceive our bikes on a given day.
Slightly different example: sometimes I love the sound of my pipe and think it's not loud and sometimes when I have a bad day it annoys me and I keep shifting at 5K just to keep it quiet...
Kinda like a GS with an exhaust "feels" faster just cause it's louder ;)
-Jessie
Quote from: mass-hole on September 01, 2011, 11:35:44 AM
I dont know about gas mileage, but i do notice that the bike seems a bit smoother and happier on 93 octane here in MA.
I notice differences from station to station.
In practice, if you have detonation or pre-ignition issues, even relatively mild ones, premium will make the bike run better. A good spark plug inspection can help identify any such issues. Otherwise, I'd expect the bike to run better and make more power on regular.
Quote from: mass-hole on September 01, 2011, 11:35:44 AM
I dont know about gas mileage, but i do notice that the bike seems a bit smoother and happier on 93 octane here in MA.
I hear this type of claim again and again..Hey, you can't argue with success, right? Well I can!
The trouble is that concepts like "smoothness" and "happiness" are really subjective. It's the percemption is reality kind of thing....
The only way I would be convinced, is if we got say 20 GS500 bikes and riders...and did a "mythbusters" type of blind test......giving riders tanks of gas, without them knowing what kind of gas......and then seeing they can identify what type of gas purely by the "feel" or the sound, or the happiness....we could also do mileage tests.......it would be quite and undertaking however....filling and emptying tanks......checking all the other variables too...
Cookie
Quote from: kml.krk on September 01, 2011, 12:41:31 PM
So let me tell you s short story...
I am coming back home from school few days ago and I notice that my bike feels really smooth and edgy like it had a bit more power. I am thinking "this is nice" and I play with throttle a bit, speed up slow down and try to come up with a reason why it feels better.
Then I realized that I fuelled it up with Premium gas because the gas station was out of regular due to Hurricane Irene. I keep going home, flick of a wrist 2nd, 3rd gear, 70mph, I am thinking: shoot I need to slow down, and I do.
I kept enjoying the ride and then I suddenly recalled this thread about Regular vs Premium gas. I was thinking to myself that there must be something to this Premium gas myth, even though I have done a research many times and knew better.
And then I recalled one more thing... It was my car that I filled with premium and not my bike...
So what I am trying to say is that unless you can precisely measure power output and smoothness of the ride, it is safe to assume that both grades of gasoline give you the same results. It is all in our heads how we perceive our bikes on a given day.
Slightly different example: sometimes I love the sound of my pipe and think it's not loud and sometimes when I have a bad day it annoys me and I keep shifting at 5K just to keep it quiet...
Perception vs reality..
Cookie
Quote from: burning1 on September 01, 2011, 03:22:59 PM
Quote from: mass-hole on September 01, 2011, 11:35:44 AM
I dont know about gas mileage, but i do notice that the bike seems a bit smoother and happier on 93 octane here in MA.
I notice differences from station to station.
In practice, if you have detonation or pre-ignition issues, even relatively mild ones, premium will make the bike run better. A good spark plug inspection can help identify any such issues. Otherwise, I'd expect the bike to run better and make more power on regular.
How do you "see" detonation by looking at the spark plug??? I could "see" mixture....or "see" oil fouling.....or "see" heat range....but I though you "hear" detonation......
A motor designed for regular, with no mechanical problems, will most likely run just the same on regualr and on premium.......premium will just waste money.....
Somtimes an engine designed for regular gets "carboned up" which causes an actual increase in compression due to the build up....then it may get knock...and may not knock on premium......but I consider carboned up to be a mechanical problem...
Cookie
Quote from: twocool on September 01, 2011, 08:08:16 PM
How do you "see" detonation by looking at the spark plug??? I could "see" mixture....or "see" oil fouling.....or "see" heat range....but I though you "hear" detonation......
You do "feel" detonation while riding but if ignored it will eventually physically damage the spark plug.
-Jessie
(http://www.xs11.com/forum/images/tips/20020915-plug_preignition.jpg)
It's amazing how different people focus on different opinions about octane...
twocool basically has it...if your engine is rated for regular fuel (Euro-Aussie ~ 91, North America ~ 87) puting higher octane in the tank won't hurt the engine, but won't help either...yes, you may notice a difference but as twocool stated:
Quote from: twocool on September 01, 2011, 08:08:16 PM
Somtimes an engine designed for regular gets "carboned up" which causes an actual increase in compression due to the build up....then it may get knock...and may not knock on premium......but I consider carboned up to be a mechanical problem...
Cookie
Usually it isn't an increase in compression that causes detonation or "knock"...it's the carbon build-up retaining heat and causing detonation...but same result...you get "knock" and using a higher octane fuel will "mask" the problem...
(I think mister suggested this earlier in the thread...about the higher octane masking the problem)
Octane itself is a rating of the fuels ability to resist detonation...basically it is a rating of what temperature will autoignite the fuel...if heat due to higher compression, carbon deposits, impurities, etc are causing knock, a higher octane rated fuel will make the engine run smoother (since it won't be firing before top dead center) and make it seem to have more power, when really it is the same power but running better due to not igniting prematurely...
As for the different stations giving you different results, it's because the different refineries have different additives in their fuel mixtures...some are better for colder climates, some have more cleaning agents...some have more impurities in them...and that is usually what leaves the deposits in the engine that makes you want to use premium fuels...
There is nothing "hi-tech" about the GS, it is a basic commuter set up bike and requires only regular fuel...if you find it runs better on higher octane fuel, run it...just know that your engine could use an overhaul to go back to running regular...probably just easier and cheaper to run the premium...
Anyway, I know there is no one answer that will convince everyone so continue with the debate...it comes up atleast once a year anyway...
Later.