Better mileage at 87 octane compared to 91

[GTPAddict]

Nah, the problem isn't that your octane is too high, it's that we (the US) use a different formula for calculating octane...


[toomuchinformation]

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.[1] 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.

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 Canada and the United States is 4 to 5 points lower than the rating shown elsewhere in the world for the same fuel.

[/toomuchinformation]

 

[YZF73]

in belgium it's 95 or 98 ... there's not even a thing like 87

Yes, in Romania the same, 95 or 98. Maybe we can dilute it with something

I think you'll find that your countries use the RON fuel rating/testing system as we do in the UK.


Yamahaboyz

 

[YZF73]

Nah, the problem isn't that your octane is too high, it's that we (the US) use a different formula for calculating octane...


[toomuchinformation]

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.[1] 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.

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 Canada and the United States is 4 to 5 points lower than the rating shown elsewhere in the world for the same fuel.

[/toomuchinformation]

Beat me to it!!! :spank:

 

[Phil_RC_1]

I read a good article one time about fuel ratings. It was writen by a retired chemist so I gave the article "some" creditability (You just have to be careful who you read, and take anything these days with a grain of salt). I don't remember a lot of the technical details, but what I retained from the article was to use the octane rating best for your particular engine, and that octane rating is a measure of how fast the fuel burns under compression, and octane rating alone, is not a "Quality" standard, (ie Higher octane is not a "better" or higher "quality" fuel).

He went on to suggest an experement of trying different octanes, making sure to only use the same brand during the experiment since additives that different brands use could scew the results of the experiment. Then try different brands. Obviously, some brands do put in different additives which, in my opinion, is a "quality" factor.

IMHO, Shells additives seem to be decent. I have no real objective data to back that up, but my bike just seems to run smoother on 87 Shell, but I get better MPG using 87 BP,,,,,,,,,, go figure!!!!

 

[banjoboy]

I always get the 87, but usually at a name brand station.
Not sure where the op is, but here in da golden state, they use a "winter formula" (Basically it's just watered down gas, and they charge us LOSERS more for it!) and fuel mileage always drops from like November to May.
You should be able to get better mileage from a higher octane only because it allows you to lug the engine, and ride around at lower rpms. (But who wants to do that?) :BLAA:

 

[mave2911]

Difference between RON and AKI
Because of the 8 to 10 point difference noted above, the octane rating shown in Canada and the United States is 4 to 5 points lower than the rating shown elsewhere in the world for the same fuel.

Excellent info, many thanks!

Now my question is whether the Japanese manufacturer has used the regional info when they've specified 87RON recommended, or whether they've used the US/Canadian units of measure (AKI)?

This being said, I can't see where is specifies a grade of fuel - in the service manual, the only thing I can see is 'Unleaded Fuel Only'.

Based on the 4-5 point difference, I'd go to say that our 91 is actually 87? (remembering I hardly think the Japanese would use a US/Canadian unit of measure.)

So - what grade of fuel should I be running?

LOL!

Cheers,
Rick

 

[red_rock_beetle]

Excellent info, many thanks!

Now my question is whether the Japanese manufacturer has used the regional info when they've specified 87RON recommended, or whether they've used the US/Canadian units of measure (AKI)?

This being said, I can't see where is specifies a grade of fuel - in the service manual, the only thing I can see is 'Unleaded Fuel Only'.

Based on the 4-5 point difference, I'd go to say that our 91 is actually 87? (remembering I hardly think the Japanese would use a US/Canadian unit of measure.)

So - what grade of fuel should I be running?

LOL!

Cheers,
Rick

104 aki:ban:

 

[ChevyFazer]

104 aki:ban::d

mothballs ftw!!!!

 

[deeptekkie]

I have to agree with you. I have noticed on my bike that it gets better mileage and actually seems to run slightly better with regular. I have an engineering buddy who is extremely sharp and he said actually that is exactly what should be happening, since the engine is tuned and built for this octane! I dunno man. I still put some high-test in about every third or fourth tank anyway.

 

[airoh69]

95 98 and 100 octane here. I always use 100 octane. Seems the bike runs smoother and outputs better mileage.

 

[Astennu]

I'm running mine on BP ultimate or Shell V-power. I think its 97. Where normal fuel is 95 over here.
I dont know if i have better milage on normal 95. But on the V-Power i can get 1:20 (liter-KM) does not seem to bad).

I have a 2009 S2 with Laser Exhaust.

 

[Dave in Houston]

I agree for the most part, but "premium fuel" has a higher grade (usually more detergents) than the 87 octane version. My father is a chemical engineer for BP. The same fuel that goes to Exxon stations may very well come off the same tanker that goes to the Quickie Mart, the only difference is the respective additive packages blending before shipment to the stations.

I think you misunderstood what your father was telling you.

Among a given fuel grade sold at different brand gas stations, the only difference may be the additive package. But refineries control to different octane rating specifications for the three grades, and these days they usually use on-line analyzers to be sure they are blending material that meets the specifications.

Straight chain hydrocarbons generally have a low octane rating. They can be reacted over a platinum catalyst to form aromatic hydrocarbons (benzene, toluene, xylene) that have a higher octane rating. The refineries call this stream "reformate."

The other common way to make high octane blending components is in the alkylation unit, where unsaturated materials like propylene and butenes are reacted with isobutane. (Edit: Which makes a branched chain with higher octane rating. The refineries call this stream "alkylate.")

Oxygenates also have a higher octane rating. In the US, ethanol is the main oxygenate, but overseas they also blend a lot of ethers.

Normal butane (which is a straight chain) is fairly high octane, but it is too volatile to fit in the gasoline pool in the summertime, when the regulations call for a lower Reid Vapor Pressure (RVP) specification in order to reduce pollution.

So the higher the octane rating, the more of the high octane (more costly) material is required to meet the octane specification.

I know this because I am a chemical engineer specializing in control systems, and in the past I've been involved with gasoline blending control.

(Now that's what I call too much information.)

 

[mave2911]

That was a fantastic post Dave!

Depending on whether I followed it, my summation of your post is that, especially in winter, when more high octane additive is needed, fuel economy will drop. If that is the case, I don't know whether that applies in Oz.

Then, if the higher octane or premium fuels contain more detergents and the like, you'd be better off with the midrange 91 (95RON for us) as this would contain a balance of economy AND cleaning?

I am most interested in the technology, so no such thing as to much information....

Thanks again.

Cheers,
Rick

 

[fb40dash5]

I've always heard that the higher the octane, the lower the energy content by volume. I don't know if it's 100% true, but it seems to make sense. Heck, ethanol's octane is through the roof, but it's got far less energy than gasoline.

Using higher-than-required octane fuel for the octane number is a waste of money. If the engine's not predetonating, it's not predetonating... using higher octane fuel isn't going to make it negative predetonate.

I've put regular (87 AKI) in my bike since I bought it last year, and haven't heard it ping yet.

 

[GTPAddict]

Excellent info, many thanks!

Now my question is whether the Japanese manufacturer has used the regional info when they've specified 87RON recommended, or whether they've used the US/Canadian units of measure (AKI)?

This being said, I can't see where is specifies a grade of fuel - in the service manual, the only thing I can see is 'Unleaded Fuel Only'.

Based on the 4-5 point difference, I'd go to say that our 91 is actually 87? (remembering I hardly think the Japanese would use a US/Canadian unit of measure.)

So - what grade of fuel should I be running?

LOL!

Cheers,
Rick

Here ya go Rick. They show it both ways.

Seems I've been wrong. I filled with 87 Friday and rode about 30 minutes today. So far the bike may actually feel better, but I need to ride a familiar route (like to and from work) to verify this. I'll check my fuel mileage as well and let ya'll know if that changes.

 

[Dave in Houston]

That was a fantastic post Dave!

Depending on whether I followed it, my summation of your post is that, especially in winter, when more high octane additive is needed, fuel economy will drop. If that is the case, I don't know whether that applies in Oz.

Then, if the higher octane or premium fuels contain more detergents and the like, you'd be better off with the midrange 91 (95RON for us) as this would contain a balance of economy AND cleaning?

I am most interested in the technology, so no such thing as to much information....

Thanks again.

Cheers,
Rick

The octane specification is the same in the winter, but the vapor pressure spec is higher. That means more butane will fit into the gasoline pool in the winter. But butane doesn't have a particularly high energy content per gallon, so the fuel economy may drop. (I found a reference that said gasoline RVP in Australia is limited from October 15 to April 15, but it looks like the spec varies by state, which makes sense if the state lines are similar to the summer temperatures.)

The detergents and additives are a very small percentage of the fuel's volume, so I don't think they weight heavily on the energy content per gallon. As far as I know, most fuel marketers use the same additive package in all the grades, so I din't think that's the reason to choose any particular grade. Personally, I avoid the mid-grade because fewer people use it, so it can sit around longer before you buy it, and when it sits around, some of the lighter materials can evaporate.

By the way, I don't have any special knowledge of the additive packages. I was only involved in making the base gasoline. The additives are normally added at the shipping terminal.

For what it's worth, my own practice is to run a good brand regular grade gas in my FZ6.

 

[Dave in Houston]

I've always heard that the higher the octane, the lower the energy content by volume. I don't know if it's 100% true, but it seems to make sense. Heck, ethanol's octane is through the roof, but it's got far less energy than gasoline.

I think this might be true as a general rule, but when I think of the many chemical species that go into gasoline, there are lots of exceptions, so you can't bank on it. It just depends what the refiner is blending.

As far as ethanol goes, think of it this way: We get energy out of fuel by reacting it with oxygen to form carbon dioxide and water. Since ethanol already has some oxygen in it, you can think of it as being partly burned, so there's not as much energy left to extract.

The advantage of burning ethanol and other oxygenates is that since they carry some oxygen along with them, they reduce the amount of carbon monoxide formed during combustion.

 

[Dave.TX]

If you want to see every fill up on my FZ6 go here. I always used 87 octane, what was recommended by Yamaha. Never tried anything different. My mileage varied not because of the fuel I used but because of my right wrist and whether I did more city or more highway miles. Got anywhere from 38.5 to 60.8 MPG, averaging about 45 most of the time.

The bike had plenty of performance so no need to "try" other octanes and such. Just used name brand onacounta the additives. Top Tier gas is pretty much all I use with some exceptions. I don't run fuel cleaners because there's no need to. Cheap no-name mystery gas rarely see's my gas tanks. Oh, and ARCO. That stuff is complete junk but thankfully not available in Texas. Two cents.

 

[VEGASRIDER]

So according to Dave, there is a difference in the quality of fuel between Shell, Chevron versus the no name brands. Glad that 90% of my fill ups are at Chevron.

Now what does the 10% blend in I forgot what you called have a effect on our mileage our performance? I noticed that the pumps in Idaho had a warning sticker that contained a certain chemical, but I never noticed the sticker while I was down in Vegas.

Ethenol

 

[Downs]

So according to Dave, there is a difference in the quality of fuel between Shell, Chevron versus the no name brands. Glad that 90% of my fill ups are at Chevron.

Now what does the 10% blend in I forgot what you called have a effect on our mileage our performance? I noticed that the pumps in Idaho had a warning sticker that contained a certain chemical, but I never noticed the sticker while I was down in Vegas.

Ethenol

Most of the fuel (the base fuel) in your area comes from the same refineries and tanks/pipes no matter if it's a Shell, or an E-Z Mart. Where they differ is in their additive packages.

For your second paragraph-
Ethanol. And you will see a drop in mileage using Ethanol compared to "pure gas". They blend it in at 10 percent but independant testing has shown a wide range of actual blend percentages between different gas stations even in the same town. Higher than 10 percent concentrations can damage your fuel system (ethanol eats rubber components) in the long term unless you have a vehicle designed to run it such as the flex fuel vehicles the big three put out. When I'm in the NOrthern part of the state or up in Oklahoma I like to buy gas cause you can find non-ethanol stations up there.

It's about retarded as an alternative fuel when you make it out of corn because you expend more energy to make it then you get out of it. It became so popular and pushed on us by the .gov when they were handing out subsidy money by the truck load for corn crop growers who participated in growing crops to make ethanol. I heard the subsidies were stopped earlier this year. Not sure if it ever did happen.