Does higher-octane petrol really make your car perform better?

Should you spend a little more on Ron97 or Ron98, or is Ron95 good enough?

Many drivers believe that higher-octane petrol automatically gives their car more power, better fuel economy or even a cleaner engine. While there is some truth behind these claims, the reality is a little more complicated.

Here's what you need to know before your next fuel stop.

First, what does Ron actually mean?

RON stands for Research Octane Number, which measures a fuel's resistance to engine knocking or pre-ignition.

Engine knocking happens when the air-fuel mixture ignites too early inside the engine, creating uncontrolled combustion that can reduce performance and potentially damage the engine over time.

A higher RON fuel is better at resisting knocking under higher compression.

However, this doesn't mean it contains more energy or is a "higher-quality" fuel. It simply means it is designed for engines that operate under higher pressures.

Does Ron97 or Ron98 make your car faster?

The short answer is: only if your car is designed for it.

Many modern performance cars and turbocharged engines are engineered to run on higher-octane fuel. These engines can take advantage of Ron97 or Ron98 to deliver their intended performance.

However, if your car only requires Ron95, filling up with Ron97 or Ron98 is unlikely to make a noticeable difference in acceleration, horsepower or fuel economy.

In other words, paying more doesn't always mean getting more.

Which petrol should you use?

The simplest answer is to follow your vehicle manufacturer's recommendation.

If your owner's manual says:

• Minimum Ron95 — Ron95 is perfectly suitable, although using a higher octane is generally acceptable if you choose to.
• Minimum Ron97 — You should use Ron97 or higher.
• Minimum Ron98 — Stick to Ron98 or above if specified by the manufacturer.

You can also check the inside of your fuel filler flap, as many vehicles display the recommended octane rating there.

Using the correct fuel helps your engine perform as intended while avoiding unnecessary costs.

Is higher-octane petrol better for your engine?

This is one of the biggest myths among drivers.

Higher-octane fuel isn't automatically better for every engine.

If your car is designed for Ron95, using  Ron97 or Ron98 won't magically extend your engine's lifespan or prevent wear.

In fact, regular servicing, timely oil changes and proper maintenance will have a much greater impact on your engine's health than filling up with a higher octane than necessary.

Does premium petrol clean your engine?

Some premium fuels contain detergent additives that help reduce carbon deposits and keep certain engine components cleaner.

However, these additives are determined by the fuel brand and product, not simply by the Ron number.

For example, one company's Ron95 may contain a different additive package from another company's Ron97. It's important not to confuse octane rating with the cleaning additives included in a particular fuel.

What happens if you accidentally use the wrong petrol?

If you accidentally fill up with a higher Ron than your car requires, there's usually no cause for concern. The car will still run normally, although you may not notice any additional benefits.

If you accidentally use a lower Ron than recommended, avoid making it a habit. Some modern vehicles can adjust engine timing to reduce knocking, but performance may be affected. 

In certain cases, prolonged use of fuel below the recommended octane rating could increase the risk of engine damage.

If you're unsure, refer to your owner's manual or consult your vehicle manufacturer.

So, is higher-octane petrol worth paying for?

It depends on your car.

If your manufacturer recommends  Ron97 or Ron98, then yes, it's worth using the correct fuel because your engine was designed to operate with it.

However, if your car only requires Ron95, choosing a more expensive fuel is unlikely to provide noticeable improvements in everyday driving.

Instead of paying more at the pump, you're often better off investing in regular maintenance, keeping your tyres properly inflated and adopting smooth driving habits, all of which can have a bigger impact on your car's performance and efficiency. 

Frequently asked questions

Can I switch between Ron95 and Ron97?

Yes, as long as both meet or exceed your vehicle manufacturer's minimum recommended octane rating.

Does Ron97 improve fuel economy?

Not necessarily. Unless your engine is designed to benefit from higher-octane fuel, you're unlikely to notice a significant improvement in fuel consumption.

Is higher-octane petrol cleaner?

Not by default. Engine-cleaning properties depend on the fuel brand's additive package rather than the octane rating itself.

Can I mix Ron95 and Ron97?

Yes. Mixing different octane ratings is generally safe, provided the resulting fuel still meets your vehicle manufacturer's minimum recommendation.

How do I know which petrol my car needs?

Check your owner's manual or look inside the fuel filler flap. Your vehicle manufacturer will specify the minimum recommended RON for your engine.

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This article was first published in Motorist.