Subscribe lor sit amet, consectetuer adipiscing elit. Praesent aliquam, justo convallis luctus rutrum, erat nulla fermentum diam, at n. Why E10 is not recommended for some newer cars?
Australian Design Rules (ADR) are harmonized with international standards as specified in the UN ECE Regulations. The same requirements apply throughout the European Union.
New Vehicles certified to these standards will increasingly use advanced emission control technologies that strictly control the engines operation parameters and have therefore more stringent fuel quality requirements.
The maximum level of ethanol blended fuel in Europe is E5. Depending on what markets certain models are sold in, Australian vehicles may be built to either a European Specifications (E5 compatible) or some other specification that is E10 compatible. This is the reason recommendations regarding E10 suitability will differ from one manufacturer to another.
The use of E10 petrol in vehicles that are E5 compatible may also result in material compatibility problems in the fuel system.
Carburettor Equipped Engines
Vehicles made before 1986 vehicles were predominantly equipped with carburettors and steel fuel tanks.
The use of ethanol blended petrol in engines impacts the air/fuel ratio because of the additional oxygen molecules within the ethanol's chemical structure.
Vehicles with carburettor fuel systems may experience hot fuel handling concerns. This is because the vapour pressure of fuel with ethanol will be greater (if the base fuel is not chemically adjusted) and probability of vapour lock or hot restartability problems will be increased.
As a solvent, ethanol attacks both the metallic and rubber based fuels lines, and other fuel system components.
Ethanol also has an affinity to water that can result in corrosion of fuel tanks and fuel lines. Rust resulting from this corrosion can ultimately block the fuel supply rendering the engine inoperable. Water in the fuel system can also result in the engine hesitating and running roughly.
Exhaust And Evaporative Emission Levels
Lean-out resulting from the oxygenating effect of ethanol in the fuel may affect exhaust emissions.
Fuel containing ethanol can increase permeation emissions from fuel system components, particularly those that have aged for nearly 20 years. Therefore the increased vapour pressure of fuel with ethanol (if the base fuel is not chemically adjusted at the refining stage) will lead to increased evaporative emissions.
Source: Australian Workshop Magazine