FUEL OCTANE RATINGS


 Hereís a couple of examples for high performance recreational vehicles -

Personal Water Craft made in USA -
FUEL TYPE SUPER UNLEADED GAS
Minimum Octane number 91
 Here you can see there is no specification for which type of octane number is referred to, but knowing it was made in the USA primarily for that market, it will be AKI as that is required on petrol pumps by law there.

Off-road All Terrain Vehicle, made in Asia -
FUEL TYPE SUPER UNLEADED GAS
Octane 91 ( R + M ) / 2 or higher
 Here more info is provided about which octane is required. "(R + M) / 2" means Research plus Motor, divided by two, which is exactly the way that AKI is calculated. However, the term AKI is only commonly used in the USA, so the method of calculating is often listed for more international models.

Light Aircraft engine, made in Europe -
FUEL TYPE Leaded or Unleaded, or Avgas 100LL
Octane Minimum RON 95, 91 AKI

 Hereís a different way of saying basically the same thing. Most gasolines that meet 91 AKI will also be 95, or more RON. Both are listed here so that different markets will be able to recognise the correct local grade. The low lead version of Avgas (100LL) is also listed because where this engine is used itís likely to be available and meet the requirements.
 In Australia or New Zealand all three of the above engines would need to use PULP or a higher octane fuel, to meet the minimum requirements. Thatís because when you look behind the numbers and determine the specís are written primarily for the North American market, then itís clear that we need 91 AKI or 95 RON. However if you just noticed the "91" and thought to yourself "Thatís the RON number for ULP, so ordinary unleaded is OK", then you could very soon be in for expensive engine trouble.
 How can you tell? Itís not easy because recreational vehicle fuel requirements are written for the most likely country of destination. In the English language thatís usually North America, but not always. If you canít tell just where the vehicleís fuel requirements are intended for, then itís usually safe to assume itís North America and consider the octane number to be AKI. That way you might end up spending a little more on fuel, but itís much better than the severe engine damage from detonation that result when you use a low octane fuel in a high performance engine. >>>>>>>

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