95-Octane vs 98-Octane – Which is Better?

You realised that your car is out of fuel and you’ve head to the nearest petrol kiosk to top up on petrol. Standing beside the petrol pump with 3 types of fuel to choose from – which one is the better petrol for you?
Most drivers may assume that the higher the number on the petrol tap, the better the fuel quality. However, as mentioned in our previous article: The Cost of Different Types of Petrol for Rental Cars, car rental service users can note that the 98-Octane fuel cost about ~18% to 29% more than its neighbouring 95-Octane fuel, while costing ~19% to 31% more than the 92-Octane fuel!
However, the million dollar question lies: Is paying more for the expensive fuel justified?
Why are some oils costing more than others? Rather than the colour of the pump, customers of car rental services should instead take note of the number beside the Octane. Here is all you need to know about the 2 most popular fuels in Singapore and how they compare to each other.

Research Octane Number

In the world of processed fuel, the Octane Number measures the knock resistance of gasoline. Ranging between 0 – 100, it describes the fuel behaviour when it combusts in the engine. Generally, a higher octane number denotes the better the fuel’s resistance to pre-ignition. With greater resistance comes an increased efficiency of the fuel and thus provides better performance of the engine.


Now, one may ask how the Octane Number affects the rental car.
Put simply, one of the benefits of the 98-Octane petrol is its greater knock resistance. Knock resistance is the fuel’s ability to not self-ignite and burn uncontrollably while fuel is being compressed in the engine. Ever heard the ‘knock’ from your engine before? It’s the pinging sound heard when the petrol is unable to resist the high compression pressures and explodes unexpectedly. Repeated knocking of the fuel due to lower octane levels could result in serious damage to the inner linings of the engine. With 98-Octane, the fuel is better able to burn in a relatively more controlled manner as compared to its counterparts.
Additionally, higher octane fuels contain additives that help clean the internal components of the engine. This helps keep the engine quality healthy while allowing the engine to run at higher compression levels. It also reduces the number of major maintenance required for the car as the car’s engine is protected with the use of the right petrol.
Thus, for long term car rental customers, it is certainly a point of consideration in using the 98-Octane, as it protects the engine of your car, and minimizes the need for heavy overhaul of the engine during maintenance.


Well, it depends. With better fuel efficiency through controlled combustion, less 98-Octane fuel is used as there is less fuel being wasted during incomplete combustion. Thus, this increases the mileage between pumps. This saves petrol costs over time, ideal for long term car rental customers.
While it may be true for some drivers, this rule of thumb does not apply to all. This is because the fuel efficiency also depends on driving habits and behaviours like driving at a constant speed. Aggressive driving habits like speeding, breaking or sudden acceleration of the car causes the engine to work harder, burning and wasting more fuel, regardless of the type of fuel pumped. To achieve optimal fuel efficiency, it is best to drive cruising at a constant speed. Additionally, depending on vehicles type, the recommended speed range for optimal fuel efficiency would be at 56km/h to 80km/h.
A rule of thumb: instead of looking at the speedometer, it is sometimes useful to glance at the tachometer, which measures how hard the engine is working and aim for the lowest revolutions per minute (rpm) while having enough power to maneuver the car smoothly.
To obtain more information about fuel efficiency tips, read ‘8-Fuel Efficient Tips For The Singaporean Driver’ to maximize the value of your petrol.


In terms of the environmental benefits of using higher octane fuels, the effects have also been rather mixed. In general, fuel efficiency depends more on the engine’s performance, rather than the fuel quality. The better the rental car engine’s performance, the more fuel efficient and better the environmental impact of using the fuel.
For a 98-Octane fuel to be fuel efficient, the engine has to be high performing enough to combust the fuel effectively, leaving little remnants and residues behind. Placing the 98-Octane in a below-average engine would actually cause the reverse effect as the engine may not be able to sustain the right temperature and pressure to combust the fuel, leaving behind incompletely combusted fuel. Therefore, for environmentally-friendly users, it is best to check with the car rental company on the specified type of fuel that is recommended by the engine manufacturer of the car rental vehicle.

So, In Summary… Which Fuel is Better?

In summary, the fuel efficiency of the 95-Octane vs the 98-Octane are rather comparable. The 98-Octane fuel is generally more efficient, allows for greater engine protection and reduces the environmental impact only if the engine of rented cars are equipped to handle the higher quality fuel.
For better performing engines, using the 98-Octane would allow you to be more fuel efficient and allow the engine to function optimally. Using the 95-Octane for these vehicles, would undoubtedly damage the engine in the long run, due to its incomplete combustion. For regular performing engines, using the 95-Octane fuel would be equally beneficial. The boring, but more important piece of this fuel justification puzzle, is actually the driver’s car safe and responsible driving habits.

What Car Rental Companies Recommend?

Most car rental companies typically recommend customers to refuel their rental car tank with at least 95-Octane fuel. 95-Octane fuel is the standard type of petrol that is suitable for almost all types of vehicles and is suitable for travels on local roads. The 98-Octane fuel is advisable for cars with engine capacity well over 2000cc as it reduces engine damage of these high-end cars. To know which of your rental cars might need the 98-Octane fuel, car rental service customers can find the recommended Octane rating for your car on the inside of the fuel cap. Alternatively, car owners can find it also in the car’s manual. When in doubt, you may also contact BizLink Rent-A-Car Pte Ltd. and our sales associates will do our best to respond to any of your queries during the course of your rental period.

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