Ethanol Fuel, what’s it all about?

Andrews High Tech Automotive - Ethanol Fuel

Currently there are two types of Ethanol blend fuel available in Australia, E10 and E85.

What is E10?

This fuel is a blend of standard unleaded petrol combined with up to 10 percent ethanol. This fuel is marketed as a 91 octane (research octane number or RON) but more commonly has an octane rating around 94 (RON) Currently it is estimated that approximately 70 percent of vehicles on Australian roads will accept E10.

E10 is generally not recommended for vehicles built before 1986 or vehicles that have engines fitted with carburetors. The solvent qualities of ethanol can lead to internal blockages within a carburetor and create running problems. For an up to date list on vehicles that are compatible with E10 visit the FCAI (Federal Chamber of Automotive Industries) website at;

What if I have been using unleaded fuel for a long time and want to switch to E10?

Ethanol has better solvent qualities than unleaded petrol. Therefore any deposits of built up residues in the fuel tank may be dislodged and collect in the fuel filter. I would recommend as a precaution that after running for approximately 1,000km on E10 fuel, the fuel filter in your vehicle should be replaced.

If your vehicle is not listed as compatible with E10 fuel and you decide to you decide to use it, be warned it can lead to some costly repairs. The vehicle will become harder to start when the engine is cold. The rubber components throughout the fuel system will be damaged resulting in further running problems with the vehicle. If you can not obtain regular unleaded fuel for this type of vehicle then premium unleaded should be used.

What is E85?

E85 is a blend of up to 85% ethanol and unleaded petrol. The octane rating of E85 can be as high as 105 (RON) Vehicles designed to run on E85 are vastly different to the normal modern motor vehicle. All bare aluminum, magnesium and rubber components in contact with this fuel have to be eliminated. Galvanised fuel tanks now have to be stainless steel. Special electronic fuel pumps have to be used in the fuel tanks.

When using E85, an increase of fuel into the engine by as much as 40% may be required to achieve the same level of performance as the vehicle running on regular unleaded. This calls for a completely different fuel injection system into the engine.

What sort of fuel consumption could I expect?

As ethanol has lower energy content than unleaded petrol, an increase in fuel consumption is expected when using these fuels. Generally when using E10 fuel expect a consumption increase of around 3%. When using E85 fuel the increase in fuel consumption can be between 30% & 40%. Engines specifically designed to take advantage of the higher octane rating of E85 may decrease this level of fuel consumption.