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What Is The Best Fuel To Use In Your Car Or Truck And Why?

What Is The Best Fuel To Use In Your Car Or Truck And Why?

Are you paying for premium fuel when you can just use regular? Are you using regular and damaging your engine? No matter what vehicle you drive, you have a choice of fuels, but which one do you pick? Regular, Premium, V-Power or Diesel?

If you own a diesel car, don’t put petrol in it as it will ruin your engine, and vice versa – don’t put diesel into a petrol engine car…

That leaves you a choice of the less expensive Regular petrol (91 octane), the mid-range Premium (95 octane, or the super-grade V-Power (98 octane). These ratings tell you one thing only – the resistance the fuel has to detonation or engine knock.

MYTH – The higher the octane number the more energy that fuel has, therefore the higher the number the better fuel economy – FALSE! All fuel has exactly the same energy content.

MYTH – certain octanes burn fuel faster or slower, hotter or cooler – FALSE! All fuels burn at the same temperature and at the same speed.

MYTH – Certain octane fuels burn cleaner, or more completely – FALSE! A more complete burn has less to do with the fuel and more to do with the fuel to air ratio inside the combustion chamber. So the octane ratings you see at the pump are just that – THE OCTANE RATING OF THAT FUEL. And the octane rating is important, octane is the resistance to detonation or engine knock, and detonation or engine know could cause damage to your vehicle. Turbo-charged, super-charged and high performance engines are more likely to get detonation if you use a lower octane fuel. With forced conduction and higher pressure there’s more heat and more pressure, and that means the fuel is more likely to explode before it’s supposed to, and that detonation (knock) sounds like a tin full of ball bearings bouncing around inside the engine making metallic pinging noises which is not good.

Many cars run perfectly fine or regular fuel. No matter what car your drive, use the manufacturers recommendation on that car. They design and build the car. If they say use premium, then use premium. If they say use regular, then use regular. There are three different methods you can use to find out what fuel your car manufacturer recommends…

  1. When you go to fill up, check your fuel filler cap to see if the recommended fuel is printed on the cap.

  2. Check your owner’s manual.

  3. Check the dashboard of your vehicle near the fuel gauge. It won’t hurt your engine if you use a higher octane fuel. If you use 95 or 98 in an engine designed for 91, that’s ok. However, it’s not acceptable to put in a lower octane fuel than the minimum recommended by the manufacturer. Using 91 in an engine designed for 95 or 98 is potentially destructive. Most modern engines will adapt (slightly) if you run them on a higher octane fuel than the minimum recommended – you will get either better economy or more performance (depending upon how you drive). In practice, the improvement is minimal, and the price of higher octane fuel eclipses the economy benefits.


In Australia we consume 20 billion litres of petrol annually, and most of the crude oil required for that comes from geopolitically unstable regions including the Middle East. Therefore, diluting our energy dependency with 10% locally made ethanol is a positive. But E10 is not a substitute for premium unleaded petrol. If your car requires 95 or 98, E10 is not a viable fuel for it. The majority of cars on Australian roads designed for 91 petrol can accept E10.