Fuel 101: Which Type of Petrol is Best For My Car?
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Fuel 101: Which Type of Petrol is Best For My Car?

Kellie Amos

Kellie Amos

26/03/2021 • 5 minute read

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Protecting one of your major assets

For most Aussies, a car is not only a necessity for our way of life but one of the biggest purchases we’ll ever make. As we all know, the financial cost of owning a vehicle continues long after that initial purchase (rego, services, insurance etc).

Since we invest so much money into our vehicles, it’s important to understand which types of fuel will help them run best. In the last few years, a number of new fuel products have popped up making things even trickier for the uninitiated. Fortunately, we’ve put together this handy guide to help you avoid any unnecessary insurance claims and keep your car out of the mechanics.

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Fun fact!

According to a 2013 study from the ABS, 46% of new car owners considered fuel economy/running costs to be their most important consideration when purchasing a vehicle.

Spot the difference: Petrol, diesel & LPG

Majority of the cars you see on the road in Australia will run on either unleaded petrol or diesel. Often, manufacturers will indicate which is right for your car on or near the fuel cap. These two types of fuels are intended for completely different engines, so it’s super important you fill your car up with the right one. Otherwise, they will do some serious damage.

In some cases, petrol cars have been modified to take LPG (liquid petroleum gas) as fuel. However, you’ll be hard-pressed to find many of these vehicles being sold today. Even some service stations have been ditching LPG bowsers because it’s no longer economically viable to have them.

Numbers matter

When it comes to petrol, there are four different types available:

  • 91 – standard unleaded petrol
  • 95 and 98 – premium unleaded
  • E10 – an ethanol-blended petrol (often a substitute for 91)


91, 95 and 98 are the ‘octane rating’ of the fuel and are roughly the same in terms of energy. Octane is essentially an index of a fuel’s resistance to burning inside your engine. When fuel burns this causes mechanically destructive high revs and large throttle openings. So, ensuring you’re filling up with the right fuel will help keep your engine healthy.

E10 is a type of fuel that contains up to 10% ethanol by volume, which is the maximum allowed by the Australian government. These days, E10 is now the ‘base fuel’ at many petrol stations and is occasionally called 94 RON. Below, we’ve broken down some of the key characteristics of the four different fuel types:

91 95 98 E10
– Compatible with most cars
– Available at most petrol stations
– Usually more expensive than E10
– Generally compatible with small turbo cars
– Increasingly hard to find
– Usually much more expensive than 91
– Used mostly by performance cars
– Often available at petrol stations
– Usually a big price jump from 95
– Not compatible with as many cars
– Available at most petrol stations
– Often cheaper than 91

Which petrol is best for my car?

Car manufacturers design their engines with a minimum octane rating in mind and you should always follow their recommendation. If you open the fuel cap on your car you should see a label of some kind, indicating which fuel is okay to use. If you lift up your cap and you see ‘unleaded petrol only’ printed on it – this means that 91 octane fuel would be appropriate for your vehicle. You can also check the owner’s manual for your car to find out which fuel is best.

Ultimately, while you can’t hurt your engine if you use a higher octane fuel than the one recommended, you should never use one that’s lower than the minimum recommendation. Using 91 in an engine built for 95 or 98 could be very destructive.

As a general rule, most of the cars made after 1986 can also run on E10. The Federal Chamber of Automotive Industries has a list of vehicle models suitable to run on E5 or E10 ethanol-blended petrol, so you can refer to that for guidance. If you’re still in doubt, make sure you double check your manufacturer’s recommendation before you fill up your car.

What about the ‘premium’ stuff?

A lot of petrol stations like to talk up the supposed ‘benefits’ of their premium fuels. But do they really make much of a difference? Well, yes, but the benefit may be a lot less than you think. Most modern engines will adapt if you run them on a higher octane fuel than the minimum recommendation. This means you could get either better economy or performance but the improvement is typically minor. Considering the price of premium, higher octane fuels, having your car run slightly better may not be worth the cost trade-off.

What about electric cars?

Obviously, electric cars don’t run on petrol but since we’re on the topic of powering cars let’s run through some of the basics.

Electric vehicles run on large batteries that you can recharge at home or at special public stations. These recharge stations are usually separate from your conventional petrol stations. Although Australia has been pretty slow to take up this new technology, electric cars are on the rise. As a result, it’s likely we’ll see more and more of these public recharging stations popping up around our major cities and service stations. You might even spot a random one in the outback.

Get the lowdown on car insurance

Now that you’ve got a better idea of how to fuel up, make sure you check out some of our other helpful guides! From window tinting to rental excess insurance, we’ve covered a wide range of topics to help you learn how to improve, protect, and insure your car.

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Oiyo is a consolidated online resource, we are not financial advisors. We work with a range of industry professionals and compliance check our articles to ensure factual accuracy. However, we do not provide professional financial advice. Consider seeking independent legal, financial, taxation or other advice to check how the information and ideas presented in this article relate to your unique circumstances.


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Kellie Amos

Written by Kellie Amos

Kellie Amos is a contributing writer for Oiyo. She has a Bachelor of Business in Marketing and a Bachelor of Creative Industries in Creative & Professional Writing from the Queensland University of Technology. Kellie has previously produced content for a range of finance companies, entertainment publications, and fintechs.

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