According to advertising and marketers, fuel additives for petrol and diesel engines can work magic on your car’s performance and emissions. For around £5 a bottle you can add the magic elixir and enjoy greater efficiency and power from your vehicle’s engine.

There are multiple petrol and diesel additives on the market too – concoctions that will increase the octane rating, inhibit corrosion in the car’s engine, provide additional lubrication or remove water from the fuel system. But do they work and will you really notice any difference to the performance or fuel consumption for your car?

The Best Fuel Additives

Before picking up a bottle from your local car care store or petrol station, it’s important to understand what each type is intended for – some are designed to clean your carburettor or improve performance, while fuel additives for diesel engines can prevent congealing in freezing temperatures. Other additives are specifically designed for petrol cars manufactured prior to 1992 to replace the lead that hasn’t been available at petrol pumps since 2000 and still others may be used if a vehicle is going into storage for an extended period.

While many of the above-mentioned fuel additives have a specific purpose, fuel additives claiming to increase fuel- efficiency and performance for any kind of vehicle are bold at best and completely unproven at worst. In fact, independent tests have shown many petrol or diesel fuel additives that claim to remove built-up carbon and dirt deposits from the engine’s moving parts or boost the amount of octane in the fuel, are simply untrue and can even decrease performance and power output.

How to Improve Vehicle Performance

If you’re driving a new vehicle or leasing one of the latest models, a fuel additive is unlikely to make any difference to your car’s performance. If you’re behind the wheel of a highly tuned sports car, like the Mercedes AMG GT Coupe, a higher octane forecourt fuel is a necessity to get the most from your ride.

It’s important to note that car manufacturers don’t recommend fuel additives for a good reason – cars are manufactured with electronic and fuel systems that are optimised to deliver the best mix of performance and efficiency anyway; if your car is under 10 years old a fuel additive won’t make a jot of difference. If it’s older you might notice a small difference, but nothing can ensure performance better than regular servicing and maintenance. Rather than tipping money away with a fuel additive, if you’d like to give your car a boost, try a higher octane fuel from the petrol station’s forecourt and take regular care of your vehicle.