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On 3 March, 2005, the South Africa Cabinet approved cleaner fuels for South Africa. This legislation has been effective 1 January 2006. Traditionally, Robin Subaru petrol engines users have been using leaded fuel. In this article we take a look at unleaded (ULP) and Lead Replacement Petrol (LRP) and the changes needed for Robin Subaru engines to operate effectively with new fuels.

Lead has been used in fuel since the 1920's. During normal operation of petrol engines, "pinging" or "knocking" takes place. Engine knock takes place when the last part of the air-fuel mixture in the combustion chamber detonates uncontrollably - this may damage the engine. In order to prevent "knocking", petrol requires a certain octane level. The octane rating of fuel is a measure of its resistance to cause knocking. The higher the octane rating, the tendency of knocking will occur. So lead has been added to fuel since 1920, as it was a cost-effective way to boost fuel's octane rating.

With technological advancement, emerged a greater awareness of environmentally friendly vehicles. Nowadays the design of vehicles using catalytic converters is standard practice. Leaded petrol cannot be used in vehicles using catalytic converters so unleaded petrol has been introduced in South Africa in 1996. The added bonus of using unleaded fuel, is that it does not emit harmful lead into the atmosphere which could adversely affect human health and the environment. Another advantage to vehicle or engine owners is that unleaded petrol does not result in formation of corrosive elements, which cause damage to spark plugs and exhaust systems. This will reduce maintenance costs.

So, which types of fuel will be available?

Government determined that 3 type of unleaded fuel (ULP) will be manufactured:

91 Research octane number
92 Research octane number
93 Research octane number

The use of different octane levels will differ based on location - for example:

If you live below 1,200m above sea level 91, 93 and 95 graded ULP will be available. At this altitude 95 LRP will also be available for use.

Living at an altitude higher than 1,200m above sea level will allow for 91,93 and 95 graded ULP with 93 LRP.

Therefore the altitude determines the type of ULP or LRP that will be available.

Unleaded petrol is generally suitable for lawnmower, motorbike and outboard engines. It is however advisable to contact your manufacturer to confirm the best type of petrol to use in your particular engine.

What about Robin Subaru engines?

Goscor Engines divisions announced that the phasing out of leaded petrol would not be a problem for Robin Subaru engines.

They recommend that engine owners decide on the most appropriate unleaded petrol (ULP) or lead replacement (LRP) petrol using only that petrol grade for their engines. It would not be a good idea to keep on switching between the different grades available.

If for some reason the grade of fuel used needs to be changed, users will have to take their engines in to the nearest service center for the engine to be de-coked. It is a simple procedure where the mechanic removes the cylinder head in order to remove all the carbon from the cylinder head to back lap the valves.

It is not advisable that engine owners do it themselves especially when service warranties are still valid. Existing Robin Subaru engine warranties will stay in tact during the phasing out of leaded fuel on the condition that engine owners submit engines at service centers for the de-coking of engines.