| Author | Message | ||
     Irideabuell |
We have friends in town from England and we began discussing fuel in our bikes. My mate said the lowest octane fuel available in the UK is 95 with 98 the norm and 101 coming to market soon. Is this higher octane rating due to metric calculations or do they really have fuel with those ratings? By the way, they are paying in the area of $12 US per gallon! | ||
| Birdy |
Someone posted that over there they use a different way of testing the octane than we do here. The upshot was that it all came out about the same. | ||
| Froggy |
Wikipedia explains it better than i can: [edit] Measurement methods 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 these results with those for mixtures of iso-octane and n-heptane. 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. MON testing uses a similar test engine to that used in RON testing, but with a preheated fuel mixture, a 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. Normally fuel specifications require both a minimum RON and a minimum MON. 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). The octane rating may also be a "trade name", with the actual figure being higher than the nominal rating.[citation needed] It is possible for a fuel to have a RON greater than 100, because iso-octane is not the most knock-resistant substance available. Racing fuels, straight ethanol, AvGas and liquified petroleum gas (LPG) typically have octane ratings of 110 or significantly higher - ethanol's RON is 129 (MON 102, AKI 116) reference[1]. Typical "octane booster" additives include tetra-ethyl lead, MTBE and toluene. Tetra-ethyl lead is easily decomposed to its component radicals, which react with the radicals from the fuel and oxygen that would start the combustion, thereby delaying ignition. This is why leaded gasoline has a higher octane rating than unleaded. http://en.wikipedia.org/wiki/Octane_rating | ||
| Irideabuell |
Wow! Thanks Frank. That's more information than I ever dreamed of getting. It just sounded odd that they would have higher octane ratings. | ||
| Loki |
as a side note They also go by the imperial gallon versus the US gallon. Gives them an extra liter of fuel. That is if my memory serves me right. | ||
| Irideabuell |
My buddy tells me fuel is sold by the liter in England. He said it's 3 US dollars per liter currently or 12 US dollars for just over a gallon (33.8 oz./liter X 4). | ||
| Froggy |
Current average in the UK is 115.5 pence per liter, which is $2.281 per liter, times 3.78 liters to a US gallon, so its $8.62 per gallon. |
