In Australia, the primary petrol types include standard unleaded (91), premium unleaded (95 and 98), E10, E85, and diesel, each distinguished by their octane ratings and ethanol blends.
Petrol Types in Australia
Arriving at a fuel station, you’re met with an array of pump labels, each representing distinct petrol types.
However, understanding the differences between them and their implications on your vehicle is key to making the right choice.
With years of mechanical expertise, the Carwreckers team unveils the nuances of Australia’s petrol landscape.
Unveiling the World of Petrol
Petrol Composition: Derived from refined crude oil, petrol in Australia has been exclusively unleaded since the phasing out of tetraethyl lead in 2002 due to concerns about lead in exhaust emissions.
This transition aimed to eliminate engine valve damage while mitigating knocking or pre-detonation issues.
Deciphering the Numbers: The numbers on fuel pumps (91, 95, or 98) signify the Research Octane Number (RON), indicating a fuel’s resistance to pre-detonation or ‘knocking.’
Higher RON numbers imply better anti-knock capabilities, critical for modern engine management.
Types of Petrol Available
Standard Unleaded Petrol (91): Widely available and a common choice, 91 RON petrol is used by older cars, though modern vehicles often require a higher grade due to loose regulations on particular chemicals, potentially damaging sensitive emissions control components.
Premium Unleaded Petrol (95): Marked as ’95’ on pumps, this fuel undergoes more filtration and refinement than 91, offering cleaner combustion, improved efficiency, and suitability for modern vehicles with stricter emissions control measures.
Ultra Premium Unleaded Petrol (98): Regarded as the highest-quality unleaded fuel, 98 RON petrol undergoes extensive refining, delivering efficient engine operation, superior knock resistance, reduced pollution, and increased power.
Ideal for high-performance models but may not be necessary for lower-grade vehicles.
E10 Fuel: Comprising 10% ethanol in unleaded petrol, E10 (equivalent to 94 RON) marks a step towards eco-friendly fuels, supporting local industries like sugarcane and corn.
Its slightly lower energy density warrants caution with older vehicles, as ethanol can be mildly corrosive.
E85 Fuel: With an 85% ethanol blend and 15% premium unleaded petrol, E85 approximates a high-grade 107 RON petrol, favoured by performance and modified vehicles.
While offering superior knock resistance and engine cooling, it significantly impacts fuel economy due to its lower energy density.
Making the Right Choice
Fuel Grade Matters: While higher-grade fuels can often be used without issues, deviating below your vehicle’s recommended fuel grade risks pre-detonation and potential engine damage. Understanding your vehicle’s ideal grade ensures efficient operation and longevity.
Manufacturers’ specifications in your owner’s manual guide the ideal fuel choice for your vehicle.
Balancing Performance and Economy: Using a higher grade than recommended might not yield additional benefits unless your vehicle is modified or re-tuned to leverage it effectively.
Understanding the complexities of petrol types in Australia empowers you to make informed decisions at the pump, ensuring optimal performance and preserving your vehicle’s health.
Does It Matter Which Fuel You Use?
Absolutely. While higher-grade fuels often pose no harm in compatible vehicles, deviating from lower-grade fuels than recommended by manufacturers can risk engine damage over time due to pre-detonation.