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What is E10 fuel, and should you be using it? Understanding different types of petrol

Filling up at the fuel station isn’t as straightforward as it used to be. Where unleaded petrol and diesel were the only options available at the pump for years, now we also have Premium Unleaded 95, Unleaded 98 and E10. So what is the difference between 95 and 98, and what is E10 fuel? And more importantly, what is the best fuel for your car? 

Here’s a quick guide to different types of petrol in Australia and how to pick the right one for you.

Understanding types of fuel

Fuels are usually classified by their chemical content, either by an RON (Research Octane Number) or their ethanol content. 

What’s the difference between Unleaded 91, 95 and 98?

The RON, also called an octane rating, speaks to how the fuel behaves in the engine. The higher the octane rating, the higher the stability of the petrol while it’s running through the engine, so the less risk there is of the fuel damaging the engine in the process of combustion. Unleaded fuels are classified by an RON.

  • Regular unleaded petrol has an octane rating of 91
  • Premium unleaded petrol has an octane rating of 95
  • Unleaded 98 has an octane rating of 98

What is E10 fuel?

Ethanol fuels are cheaper and more sustainable to produce, but they’re not more efficient – their energy by volume is lower than regular fuel.

Fuels like E10 and E85 are named by the percentage of the fuel that is ethanol. So, E10 fuel is fuel that contains 10% ethanol. The octane rating of ethanol fuel is naturally higher, which means ethanol-blend fuels like E10 are popular for performance vehicles.

What is the best fuel for your car?

You should always check your owner’s manual or ask a service technician before using a different type of fuel, but here are some pointers to help you choose the right one.

  • Standard unleaded petrol: the cheapest option at the pump, and the most popular for cars used for day-to-day commuting. Use this unless your car specifies that premium or 98 octane must be used.
  • Premium unleaded 95 octane petrol: the middle of the road in unleaded; an entry-level premium. If your car specifies that premium must be used, 95 is likely the right option, but for some newer high-performance cars, it may damage the engine. Those cars will specify that 98 octane must be used.
  • Premium unleaded 98 octane petrol: This petrol is designed specifically for high performance engines. This will definitely work if your car needs premium fuel, and may offer better mileage over 95 octane fuel.
  • E10 fuel: This blend of ethanol and unleaded fuel is cheaper than 98 octane and has an RON of 105. Usually the choice of modified performance cars. The greatest benefit is in environmental friendliness and price. E10 doesn’t necessarily offer any performance benefits, so while it’s cheaper at the pump, you won’t get as much mileage.

Remember to always check your owner’s manual or ask a qualified service technician before trying to use a different type of fuel, as the wrong choice can lead to serious engine damage. 

No appointments are required at Express Lube, and our friendly technicians know cars inside-out. Swing by for a service, parts replacement or expert advice and we’ll be happy to help!

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