Whenever you refuel at a petrol station, you’ve probably seen extra nozzles offering Premium fuel that is branded with something like “Super”, “Momentum”, or “High-performance”.
In most cases, these fuels are not worth the additional cost per litre as the vehicle’s engine management software has been developed to run perfectly on the standard fuels. However, there are exceptions to this.
Even though all vehicles must be able to run on standard 95 RON fuel (RON – Research Octane Number), premium fuels with a higher octane figure (like 98 RON) do have their benefits, but it is recommended only for high-performance cars.
With the higher RON fuel, the engine will run and perform better, with improved fuel economy but your engine needs time to adjust to using it. You will need at least 50 miles on the new fuel to start to feel or see any improvements. However, if you return to the lower rating fuel, your engine may run rough for a while as it re-adjusts.
So in reality, if you want better performance and efficiency from the higher octane fuel, you ideally need to keep using it.
In the case of diesel, things become more interesting. Super diesel fuels usually have more cleaning additives in them. This is very good for the engine as it ensures greater efficiency, which means better fuel economy.
The bonus here is that you can swap between the normal diesel and the super diesel whenever you want without it being detrimental to the engine.
We suggest that if you normally fill up with cheap diesel, then every three or four refills, you use a super diesel. The cleaning additives in the super diesel can help keep your engine in good shape. If you continue to use only cheap diesel, your car may fail the MOT on emissions.
Is it worth paying for the premium fuel?
There is no perfect answer. It really depends on the type of driver you are, your vehicle and the mileage you cover. As mentioned above, if you own a diesel vehicle it’s worth using premium diesel to give your engine a boost now and then. And this is also better for the environment.