Fuel – which should you use and why

Last updated on November 25th, 2021 at 09:13 am by Bill Tsouvalas

A lot of people might get quite disoriented when asked this question given the different types of available fuel for use. Over the last few years there has also been the introduction of more fuel types than ever before. Car owners who are not pretty enthusiastic when it comes to car maintenance may get confused when opening the fuel flap of the car.

Some cars might state “Unleaded Fuel Only” or “Premium Unleaded Only”. That’s pretty confusing for some people, are you with me? And the worst part is that the consequences of getting this aspect wrong can be quite harsh in the long run. The wrong fuel can mess up your engine, and you’ll end up paying thousands of dollars for repairs. How to avoid that? By being informed.

At the moment, the offer concerning automotive fuels is the following.

Standard unleaded petrol (ULP)

Standard unleaded petrol is octane rated at 91. In some states, it has been eliminated from the fuel market, and E10 will replace it in the future. Still, the majority of cars in Australia run on ULP. This fuel type matches the “Unleaded Fuel Only” sticker inside your fuel flap.


E10 is a fuel mix encompassing 10 percent ethanol. The majority of modern cars run on E10, some older cars as well. If you are uncertain of the type of fuel you should be using, you could discuss this aspect with the vehicle manufacturer. Some cars that are older might not be equipped with E10-proof compounds inside the fuel system. In this situation, the use of this type of fuel can lead to the breakdown of these incompatible materials. Afterwards, your fuel filters and injectors will be imminently affected.

Premium, 95-octane unleaded petrol (PULP)

This fuel type is the entry-level fuel in most markets, which doesn’t encompass 91-octane. In the case in which your car requires “Premium Unleaded Only”, as you can notice inside the filler map, this is the type of fuel you should opt for. Using 91-octane or E10 can result in serious engine damage in the long run. Also, this kind of fuel is the cheapest from the two PULPs.

Premium 98-octone unleaded (PULP)

Premium 98-octone unleaded is required by a couple of exotic cars, which present forced induction or direct injection. Pay attention if your filler map states “98-octane unleaded only” – it is strongly recommended you don’t use another petrol type because your engine can suffer from harsh damage.

E85, a combination of up to 85 percent ethanol

The composition of this type of fuel might vary by place and season. At the moment, E85 is accessible for purchase only in a couple of selected Caltex servos under the name of “Bio e-Flex”. The only cars that can run on this fuel are those designed especially for it. In more exact terms, if you have another type of vehicle, the odds are you won’t be able to turn on the engine using this fuel.

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