Premium petrol vs normal petrol: Which is right for your car?

Mileage is one of the key criteria when buying a car in India. Be it a petrol or diesel car; fuel efficiency always takes the front seat in a market where the buyers look for value for money. Modern vehicles are efficient and deliver good mileage — however, the quality of fuel matters when it comes to a vehicle's fuel economy. Read ahead as we discuss one of the most common questions among car owners: premium petrol vs normal petrol, which is right for your car?

Premium petrol vs normal petrol:  Which is the right choice for your vehicle?

When you visit a fuel station to refuel your car, you might have read these terms like premium, extra premium, power, etc. These are the names used by different oil companies for the high octane petrol. Premium petrol is different from regular petrol in terms of the octane number. Now, if you wonder what octane number is, we will explain that in the next section.

Before deciding which is the suitable petrol for your car, you need to understand the difference between the two types of petrol. The choice of fuel depends on the make/model of your vehicle. It also depends on the manufacturer’s recommendation for the type of fuel used in that particular car.

There is a common misconception that premium petrol increases performance and fuel efficiency. But it is not the case. However, premium petrol has some advantages over regular petrol. In the following sections, we explain all the details of petrol fuel, and then you should be able to decide for yourself which is a better fuel for your car.

Also, read: Petrol vs diesel car

What is petrol fuel made out of?

Before diving deep into the types of petrol, let’s take a quick look at the chemistry behind fuel production. Petrol comprises hydrocarbons such as naphthenes, paraffin and olefins. These hydrocarbons are produced through a process called the catalytic cracker. The crude oil that contains big hydrocarbon molecules breaks into small molecules in this process.

The tiny molecules are vaporized using a catalyst. After this process, finally, the petrol is extracted from crude oil. Next, additives are added to the petrol to enhance the fuel quality. A good quality fuel does not leave huge carbon deposits inside the engine.

Premium petrol

Premium petrol is a fuel with a higher octane number than regular petrol. Generally, the premium petrol’s octane number stands at 91 or higher. The premium fuel also has additives and detergents to keep the engine free from carbon deposits and sludge formation.  

Now, you may ask what octane number is? It is a number used to measure the ignition quality of fuel. The higher the octane number, the lesser the chances of knocking effect inside the engine. Knocking occurs when the fuel ignites before the spark plug produces the sparks. Hence, it is suitable for high-performance cars with high compression ratio engines.

Normal petrol

Normal petrol is a fuel with a lower octane number than premium petrol. The octane number of regular petrol stands at 87. However, in India, the regular petrol needs to have a minimum octane number of 91. Now you may ask what the difference between normal and premium petrol is? Regular petrol does not comprise any additives. Hence, it costs less than premium petrol.

This type of petrol is ideal for low compression engines. However, it is not suitable for high-performance cars with a higher compression rate as it may cause knocking.

Difference between normal petrol and premium petrol

Below are the major differences between normal petrol and premium petrol.

Extra premium petrol vs normal petrol

The extra premium petrol has an octane number of 93 or higher, and they are generally suitable for high-performance cars. The manufacturers of high-end cars also recommend high octane fuel. Below are the differences between extra premium and regular petrol.

The octane number of petrol and its importance

The octane number of petrol indicates the quality of fuel. The higher the octane number, the better the quality. Here, quality refers to the rate of compression that fuel can withstand before igniting inside the combustion chamber of an engine.

That’s the reason why most high-end performance cars use high octane petrol. The high octane fuel is suitable for engines with high compression ratios. Usage of low octane petrol in a high compression engine will lead to knocking where the fuel burns even before the spark produced from the spark plug.

However, using high octane petrol in a low compression engine does not have any ill effects. Premium petrol has additives, and they help retain the engine's efficiency by keeping the engine’s internals clean.

Difference between octane and cetane number

If you are reading this section, you may already know what octane number is. Now, coming to the cetane number, it is a scale used to measure the fuel quality of diesel. The higher the cetane number, the better the ignition quality of diesel fuel. Refer to the table below for more details on the octane number vs cetane number.

Common types of fuels on sale in India

As mentioned earlier, the Government of India has prescribed the minimum octane rating for petrol as 91. That means all oil companies need to retail 91 octane regular petrol. Below are the common types of petrol fuel available in India.

What’s the right fuel for your car?

The simple way to answer this question is to refer to your car’s owner’s manual. If the manufacturer has recommended the use of regular petrol, stick to it. There’s no point in filling up premium fuel and expecting higher performance. However, premium fuel helps to keep the engine smooth due to the additives it comprises. 

If your car’s engine is designed to work best on normal fuel, the premium or extra premium petrol will not make the car go faster. Hence, it’s best to stick to the manufacturer-recommended fuel.

If you own a premium car with a high-performance engine, premium or extra premium fuel is the best choice. Manufacturers also recommend petrol with an octane number 93 or higher for high compression engines. Hence, the choice of fuel depends on the type of car. With a minimum octane rating of 91 in India, almost all vehicles should work fine with regular petrol, provided it matches the octane rating recommended by the manufacturer.

Frequently asked questions

Below are some of the most commonly asked questions about premium petrol vs normal petrol.

Does premium petrol make any difference to the performance?

No. Premium petrol does not make any difference to the performance as the octane number is similar to regular petrol. However, it comprises additives and detergents which keeps your engine free from sludge and carbon deposits. It results in the smooth functioning of the engine.

Can I mix normal and premium petrol?

Yes, you can mix both regular and premium petrol. Since both the fuels are unleaded, it will not cause any harm to your car’s engine. However, mixing the regular and premium petrol may not extract the best out of the engine if you drive a high-performance vehicle with a high compression engine.

Does premium petrol deliver better fuel economy?

Practically, you may not notice any significant increments in fuel efficiency when running your car on premium petrol. The mileage depends on your driving style, road conditions and traffic. If you drive on a confused urban road, the fuel efficiency will naturally drop even if you use extra premium petrol.

Is it necessary to fill premium petrol?

No. Premium petrol is not necessary unless it is manufacturer-specified. The regular petrol’s octane rating in India is 91. Hence, almost all mass-market vehicles should run smoothly on normal fuel. However, filling up high octane fuel is necessary if you drive a high-performance premium vehicle.

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