Most car buyers have ‘mileage’ as the single most important criteria when choosing a new car. This is not surprising if you consider the fast increasing fuel prices. No wonder then that India is home to some of the most fuel-efficient cars ever. With cars getting lighter and developments in the technology world making engines more efficient, carmakers regularly outdo themselves and come up with an improved car with higher mileage. However, a question that often bothers many is which fuel one should choose between normal and premium?
But before we end up answering who should choose the way, let’s first get slightly into the technical side of things. Petrol comprises of hydrocarbons like paraffin, naphthenes, and olefins, which are produced through the catalytic cracker. As this process takes place, the crude oil that is made up of big hydrocarbon molecules breaks into tiny molecules, which are then vaporised using a catalyst. After all this, petrol is finally extracted from the crude oil, and certain additives are then put into it to enrich its quality for not leaving huge carbon deposits inside the engine.
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What is the Difference Between Normal vs. Premium Fuel?
The biggest difference between normal fuel and premium fuel lies in the octane number. The regular fuel boasts an octane number of 87, but premium fuel has an octane number of 91 or even more. Now, the octane number is nothing but a unit to measure the ignition quality of petrol. In diesel, this measurement is done through ‘cetane number.’ Higher the octane number of petrol (and cetane number of diesel), less will be the chances of any knocking issue as the fuel burns in the engine. Another difference between normal vs. premium fuel is the significant difference in the prices. Premium fuel is costlier and, at times, by a pretty huge margin.
Many Indian oil companies, including ICOL HPCL and BPCL, have been advertising premium fuel increases mileage and life of the engine. Most Indian premium fuels have an octane rating of 93-94, while normal fuels have an octane rating of 87. There are select outlets that even offer 97 octane fuel that is used in high-performance cars.
Importance of Octane Number
Basically, the octane number offers information on how much compression the fuel can experience before the combustion takes place. The octane number also gives a measurement of petrol’s quality and heat-bearing capacity. Basically, petrol that has a higher octane number will not combust as quickly, and this is exactly why most performance cars that come with high compression engines need to use high octane petrol in order to work efficiently and offer optimum performance and efficiency.
Here are the common type of fuels on sale in the country-
- Regular Fuel
- HP Power
- BPCL Speed
- BPCL Speed 97
- IOC XtraPremium
- 87 octane
- 87 octane + additive
- 91 octane
- 97 octane
- 91 octane
What about Diesel Fuel?
Like we said, for measuring the quality of diesel fuel, a different unit, called Cetane number, is used. The higher the cetane number, the more combustible the fuel is, and therefore, it performs better. In comparison, in petrol, a higher octane number represents that the fuel resists spontaneous ignition and hence, has less chances of knocking in the petrol motor. Both the units have been developed in a way that the higher value represents a higher quality of fuel. So, a higher cetane diesel won’t resist combustion like higher octane petrol, but they both will be best for their respective use. For diesel vehicles, the recommended centane number value lies between 40-60.
In case you use the octane scale to rate diesel, it would have a value of something between 15-25. The reason for this low value is that diesel requires to be ignited in a different kind of engine. Compared to petrol, it has lower volatility and even lower resistance to know. However, it offers higher energy for the same volume as petrol.
- Octane Number is a measurement of the quality of petrol decided as per its resistance to combust in an engine.
- The Cetane Number is a measurement of the quality of diesel based on how readily it combusts in a diesel engine.
Normal vs. Premium Fuel
In case your car’s manual recommends usage of regular fuel only, then you should stick to that. This is because your car’s engine has been tuned to work best on normal fuel, and you’ll unnecessarily end up burning a hole in the pocket by paying for something you don’t need as putting higher octane petrol in your car will have absolutely no benefit at all. Unlike what’s advertised, it won’t help your car go any faster or offer more fuel efficiency.
In case you hear repeated knocking from a car engine when using regular fuel, you can think of switching to premium fuel, but only after getting your engine inspected for a potential mechanical fault. Most cars these days have knock sensors that can adjust the ignition timing in the interest of optimum performance.
Don’t go by what’s advertised. Putting premium fuel in a car whose engine is tuned to run on normal fuel won’t have any advantage. There will be no extra power generation, and your car won’t go any faster. Also, there won’t be any fuel efficiency gains either.
All cars are tuned to perform at an optimum level on a certain quality of fuel. The carmakers spend a lot of money on R&D to decide what setting is the best. Therefore, one should stick to the manufacturer-specified recommendations and not pay extra for premium fuel in case the engine is recommended to be used on lower-quality fuel. Similarly, in case you own a performance car with a high compression engine, you should stick to the higher quality fuel recommended by the carmaker.
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