Petrol prices are constantly on the rise, and your choices at the pump are always increasing.
When it comes to your car, does it really matter which type of fuel you use?
Types of Fuel
You have seen the different names and numbers at the petrol pump. But what do they all mean?
The first thing you need to know is simply that fuels vary according to their concentration of flammable chemical octane. In Australia, these are usually 91, 95 and 98 concentrations.
Contrary to popular belief, fuel octane rating does not indicate the amount of energy in the fuel itself. Instead, it refers to how resistant a fuel is to burning under pressure.
In theory, the more resistant, the better – but we’ll get to that soon. First, let’s run through the most common fuel types.
Unleaded 91
This is the standard unleaded fuel type in Australia. Most locally manufactured and Japanese imported vehicles are made to run on Unleaded 91.
Premium 95 or 98
While they go by different names according to which service station you pull into, premium fuel types are generally 95 or 98 octane blends. Most European cars need premium fuels, since higher octane levels are standard in Europe.
E10
E10 contains 10% ethanol. This blend is harmless in most modern cars. However, a handful of newer models as well as any car built before 1986 cannot run on E10 fuels. ‘
Why?
Some fuel systems are built with E10-proof materials, which decompose when ethanol fuel is used, potentially resulting in foreign byproducts in the fuel system. These byproducts may become clogged in the fuel injectors or filter, creating engine damage that will cost you a pretty penny.
While E10 fuels are cheaper at the petrol pump, they typically create less energy than octane fuels. In many cars requiring minimum 91 octane, E10 also increases fuel consumption by around 3%. More often than not, this figure that negates any money saved at the pump.
Still unsure as to whether E10 is a good idea for your car?
Can I put higher octane fuel in my car than recommended?
In short, yes. Putting 95 or 98 octane fuel into a car that only requires 91 octane will not damage your vehicle. But it will only result in negligible changes to performance and efficiency.
Higher octane fuels will be less likely to burn prematurely (i.e. before it reaches the spark plugs) than lower octane fuels, theoretically improving fuel economy and timing. However, in a car designed to run on 91 octane fuel, not much wastage occurs anyway. This means that you are more likely to notice a different in your bank account than your overall car performance.
Can I put lower octane fuel in my car than recommended?
No, no and no again. In an engine that requires higher octane fuels, low octane blends will burn up prematurely, dramatically increasing the heat inside the combustion chamber. If the temperature climbs to a point that the engine can’t handle, extreme stress will also be placed on the internal components in your engine – a combination that can prove diabolical.
At the end of the day…
It’s safest to observe the manufacturer guidelines when re-fueling.
In addition to damaging your engine or wasting your hard-earned money, using the wrong blend of fuel can invalidate your car’s warranty.
Trust the people who built your car – they know their stuff. Don’t risk bigger problems down the track for the sake of saving a few dollars in the short term.
