OZ ATV :: The Australian ATV Forum

[4stroker]

I have always understood that fuel in the US is of a higher quality than here.

Take for example this excerpt from wikipedia:

"In most countries (including all of Europe and Australia) the "headline" octane that would be shown on the pump is the RON, but in the United States, Canada and some other countries the headline number is the average of the RON and the MON, sometimes called the Anti-Knock Index (AKI), Road Octane Number (RdON), Pump Octane Number (PON), or (R+M)/2. Because of the 8 to 10 point difference noted above, this means that the octane in the United States will be about 4 to 5 points lower than the same fuel elsewhere: 87 octane fuel, the "regular" gasoline in the US and Canada, would be 91-92 in Europe. However most European pumps deliver 95 (RON) as "regular", equivalent to 90-91 US (R+M)/2, and even deliver 98 (RON) or 100 (RON)."

Basically, it is saying that 98 octane fuel here is equivalent to say 93/94 octane in the states.

I have been talking to a few engine builders in the states regarding domes for my banshee, and they all say for our 98 (which is there 93) that the smallest dome you should run is a 21cc.

However i know for a fact that a good friend of mine has had 19cc domes in his banshee for years, and has always ran BP Ultimate (9, without a problem. pull the head on his bike and there are no signs of deto.

the other weekend we even accidentaly filled it up with regular, cats p*ss 91, flogged the guts out of it all day and it didnt miss a beat...

has anyone else had a similar experience?

are there any experts on here regarding fuel science? (long shot i know!)

thanks, mark
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2002 SE Banshee

[Quad Squad]

Its an interesting topic Mark, with lots of differing opinions in terms of what is safe and what isnt.

What you will find is that engine builders will more often than not err on the side of caution. Personally speaking, it is to allow for the "human factor" where mistakes can happen and as you know yourself when you accidentally ran regular 91. The last thing they want is a customer coming back to them and saying they have cracked a piston, because even though it can be attributed to the customers action of running the wrong or old fuel it is still on the shoulders of the builder.

Adam
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www.quadsquad.com.au
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[doorslammer]

Quad Squad wrote:

Its an interesting topic Mark, with lots of differing opinions in terms of what is safe and what isnt. What you will find is that engine builders will more often than not err on the side of caution. Personally speaking, it is to allow for the "human factor" where mistakes can happen and as you know yourself when you accidentally ran regular 91. The last thing they want is a customer coming back to them and saying they have cracked a piston, because even though it can be attributed to the customers action of running the wrong or old fuel it is still on the shoulders of the builder. Adam

yep builders are always going to play it safe then tell you what extreme you can go to

and im a fuel scientist i think
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01 Banshee
Never take life seriously. Nobody gets out alive anyway

[HSR]

HI! , It is also very important to note that the addition of oil to the 2stroke fuel mixture( ie fuel/air/oil,) also significantly lowers the RON octane rating of the fuel.Because of the diversity and differences in these oils there is No way of telling what the effect of this addition can be (unless each fuel/oil combo is tested ) so an average or safe margain is chosen, then with other factors also playing a more or less important part in the whole combustion process, the shelf life of the fuel (age ) atmospheric density (temperature,humidity,altitude,) cylinder pressure and mechanical condition (compression ) and ignition timing (both static & dynamic ) so as you can see the octane rating is just a part of the over all fueling package, the manufacturer`s and engine builders will always quote the fuel rating to cover the greatest array of these conditions because it is impossible to cover them all, and then optimum tuning is then up to the individual.
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we do not stop racing because we grow old
we grow old because we stop racing

[Linc]

One thing I have picked up as a significant difference between us and the US.......

The US method of MON/RON is a measurement that delivers the average octane reading for the fuel used.......With our method and our and government rules the RON measurement stated must be the "minimum" octane delivered.

This means that while it may say 98 octane in Australia it's often higher.

If you bought US 95 octane fuel it will be an "average" of 95 octane......could be higher, could be lower.

Thats the difference.

Linc