How to Choose Between Premium and Regular Petrol

Choosing which petrol to put in your car can be a tricky business, particularly now there seems to be so much choice on offer between different companies. We all know that premium petrol can be expensive, but do many of us really know the difference between premium petrol and it’s cheaper rival regular petrol? Here’s how to choose between the two.

Difficulty: Moderately Easy

Instructions

1. Learn the meaning of the term "octane rating". A petrol’s octane rating means the measurement of its ability to resist "engine knocking:, which happens when the fuel in the engines cylinder explodes instead of burning like normal creating a small shockwave. If a petrol has a higher octane rating, it will be more resistant to engine knocking. A petrol’s Road Octane Number (RON) is a combination of different ratings for different aspects of the gas, and is used to distinguish regular petrol (which usually has a RON of 95) from premium petrol (around 98 RON).

2. Know that for many cars, filling them with premium unleaded as opposed to regular unleaded will make no noticeable difference to their performance and will be an unnecessary expense as practically no engines require petrol with a higher rating than 95 RON. Unless you are driving a high performance sports car, or using your car to race, there’s usually no need to choose premium petrol.

3. Decide if your car does actually warrant the use of premium petrol. Some cars with turbocharged engines, or racing engines with high compression require premium petrol as standard. Most high value cars, sports cars and cars from sports brands (for example a BMW or Coupe) will benefit from being filled with premium petrol, allowing them a greater performance and quicker acceleration, although it’s by no means a necessity.

4. Decide whether the other benefits of premium petrol are worth the extra expense. Premium petrol is known to cause less pollution and maintain a cleaner engine through the detergents it contains.

5. Learn the different names for premium and regular petrol so you can choose between them at your regular filling station--not all companies use the same terms. For example, the premium petrol in BP garages across the country is known as BP Ultimate.

6. Look for the most expensive petrol on offer if you want to choose a premium petrol. Premium petrol will always be by far the most pricey petrol available, costing an average of 10 pence per litre more than regular petrol, which will add a significant amount to the average tank full.

Tips & Warnings

• The terms "premium" and "regular" nowadays only apply Unleaded petrol, since Leaded petrol was taken off sale from all national filling stations in January 2000. However, it is still possible to fill your car with Leaded petrol if required at a small number of licensed, specialist filling stations.
• Don’t fill your car with premium petrol in the hope that it will increase your car’s miles per gallon. Your car will use petrol at the same rate, if not faster, if filled with premium unleaded.
• Don’t be fooled by UK petrol companies advertising the Research Octane Number of their petrol instead of the Road Octane Number, who are using the former to exaggerate the petrol’s octane rating. Most use the Road Octane Number (which is an average of the Research Octane Number and the Motor Octane Number) which is the rating you should use to compare petrol from different suppliers.