octane rating equivalence between RON and DON?
04-07-2005, 11:44 AM
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octane rating equivalence between RON and DON?
I'm taking my car to Europe and want to know if my 93 APR chip will work there...
I know that in Europe they only show the RON. But is the MON always the same for a given RON, or does it depend on the brand? Specifically, if I buy 98 RON over there, can I trust that the MON is always 90, resulting in a DON of 94, which will be ok on my chip?
Thanks guys...
I know that in Europe they only show the RON. But is the MON always the same for a given RON, or does it depend on the brand? Specifically, if I buy 98 RON over there, can I trust that the MON is always 90, resulting in a DON of 94, which will be ok on my chip?
Thanks guys...
04-07-2005, 12:20 PM
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What is "DON"?>>
I know Europe uses RON on the pumps - Research Octane Number,
and we use R + M/2: Research octane number + Motor octane number divided by 2.
98 RON works ot to about 94 R+M/2 I think. In Germany, you can get 99 and 100 RON, at least from Shell, FWIW.
and we use R + M/2: Research octane number + Motor octane number divided by 2.
98 RON works ot to about 94 R+M/2 I think. In Germany, you can get 99 and 100 RON, at least from Shell, FWIW.
04-07-2005, 12:28 PM
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roaD Octane Number
I've seen the (R+M)/2 number called that sometimes.
when you say that 98 European is about 94 here, is that depending on the brand, or is there a fixed correlation?
when you say that 98 European is about 94 here, is that depending on the brand, or is there a fixed correlation?
04-07-2005, 01:01 PM
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RON DON MON.
The most important characteristic of petrol is its Research Octane Number (RON) or octane rating, which is a measure of how resistant petrol is to premature detonation (knocking). It is measured relative to a mixture of isooctane (2,2,4-trimethylpentane) and n-heptane. So an 87-octane petrol has the same knock resistance as a mixture of 87% isooctane and 13% n-heptane.
There is another type of Octane, called "Motor Octane Number" (MON), which is a better measure of how the fuel behaves when under load. Its definition is also based on the mixture of isooctane and n-heptane that has the same performance. Depending on the composition of the fuel, the MON of a modern petrol will be about 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 and some other countries the headline number is the average of the RON and the MON, sometimes called the "roaD Octane Number" or DON, or (R+M)/2. Because of the 10 point difference noted above this means that the octane in the United States will be about 5 points lower than the same fuel elsewhere: 87 octane fuel in the United States would be 92 in Europe.
There is another type of Octane, called "Motor Octane Number" (MON), which is a better measure of how the fuel behaves when under load. Its definition is also based on the mixture of isooctane and n-heptane that has the same performance. Depending on the composition of the fuel, the MON of a modern petrol will be about 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 and some other countries the headline number is the average of the RON and the MON, sometimes called the "roaD Octane Number" or DON, or (R+M)/2. Because of the 10 point difference noted above this means that the octane in the United States will be about 5 points lower than the same fuel elsewhere: 87 octane fuel in the United States would be 92 in Europe.
