Why are there 92, 95, and 98 gasoline? What are the differences between using different types of gasoline? How to know what type of gasoline to use when refueling in different countries? How to choose the right gasoline? Engine compression ratio, driving needs, and different atmospheric pressures and temperatures can all affect the choice of gasoline!

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The Meaning of Gasoline Octane Rating

There are three common types of unleaded gasoline in the market: 92, 95, and 98. Their octane ratings are 92, 95, and 98 respectively, which means that each type of gasoline has a different ability to resist knocking in the engine.

The classification of gasoline is mainly based on its octane rating, which is an important indicator of gasoline’s knock resistance.

The higher the octane rating, the stronger the gasoline’s ability to resist knocking. This is because high-octane gasoline can burn stably at higher pressures and temperatures, thereby reducing the risk of abnormal combustion (i.e., knocking).
The octane rating of 92 unleaded gasoline is 92, with the lowest knock resistance; 95 unleaded gasoline is slightly higher, at 95; while 98 unleaded gasoline has the highest knock resistance, at 98.

The Impact of Knocking

Knocking refers to abnormal combustion occurring in an internal combustion engine, which usually leads to abnormal vibrations and noise inside the engine. This situation often occurs when the engine is climbing or accelerating.
If low-octane gasoline below the vehicle’s design requirements is used for a long time, it may lead to engine damage, such as piston damage or valve damage. Therefore, choosing the right type of gasoline is crucial for maintaining vehicle performance.

Comparison of 92, 95, and 98 Gasoline

Gasoline Type	Octane Rating	Knock Resistance	Suitable Engines	Advantages	Disadvantages
92 Gasoline	92	Low	General naturally aspirated engines	Cheapest price, good fuel economy	Lower power output
95 Gasoline	95	Medium	Most modern gasoline engines	Balanced performance, good fuel efficiency	Moderate price
98 Gasoline	98	High	High-performance engines	Highest power output	Most expensive, poor fuel economy

Choosing the right type of gasoline is crucial for protecting the engine and enhancing performance, so vehicle owners should make informed choices based on their vehicle’s needs.

Octane Rating Calculation Method

Reference for standard oil

Isooctane (octane rating 100) and n-heptane (octane rating 0) are used as benchmarks.
The octane rating of gasoline is determined based on its comparison with these two substances in a standard engine.

Testing Method	Abbreviation	Main Features	Octane Rating Range	Usage Regions	Formula
Research Method	RON	Tests simulated under moderate speed and driving conditions, widely used in Asian countries.	Typically 92-98	Asia, Europe	-
Motor Method	MON	Tests simulated under high load and high-speed driving conditions, values are usually 8-12 lower than the research method.	Typically 80-90	USA, Canada, Europe	-
Anti-Knock Index	AKI	The rating used in the USA and Canada, which is the average of RON and MON.	Typically 87-93	USA, Canada	$$ \text{AKI} = \frac{\text{RON} + \text{MON}}{2} $$

Are There Different Octane Ratings of Gasoline in Different Countries?

Country/Region	Octane Rating Indication	Common Octane Rating Types
USA	Anti-Knock Index (AKI)	87 (Regular), 91-92 (Mid-Grade), 97-98 (Premium)
Canada	Anti-Knock Index (AKI)	87 (Regular), 91-92 (Mid-Grade), 97-98 (Premium)
Brazil	Anti-Knock Index (AKI)	E25 (85% gasoline + 15% ethanol), E100
Mexico	Anti-Knock Index (AKI)	87 (Regular), 92 (Premium)
Europe	Research Method (RON)	95 (EuroSuper), 98 (SuperPlus)
Germany	Research Method (RON)	95 (Super), 98 (SuperPlus)
France	Research Method (RON)	95 (SP95), 98 (SP98)
UK	Research Method (RON)	95 (Premium), 97 (Super), 99 (Ultimate)
Italy	Research Method (RON)	95 (Verde), 98 (Super)
Spain	Research Method (RON)	95 (Sin Plomo), 98 (Super)
Japan	Research Method (RON)	91 (Regular), 95 (High-Octane), 100 (Premium)
China	Research Method (RON)	92, 95, 98
Taiwan	Research Method (RON)	92, 95, 98
Hong Kong	Research Method (RON)	95, 98, 100
Australia	Research Method (RON)	91 (Regular), 95 (Premium), 98 (Ultra)
New Zealand	Research Method (RON)	91 (Regular), 95 (Premium), 98 (Ultra)
South Korea	Research Method (RON)	92, 95, 100
Russia	Research Method (RON)	92 (Regular), 95 (Premium), 98 (Super)
India	Research Method (RON)	91 (Regular), 95 (Premium)
Singapore	Research Method (RON)	92, 95, 98
Malaysia	Research Method (RON)	95 (Regular), 97 (Premium), 100 (Racing)
Thailand	Research Method (RON)	91, 95, 97
Indonesia	Research Method (RON)	90, 92, 95, 98
Philippines	Research Method (RON)	91 (Regular), 95 (Premium), 97 (Super)
Vietnam	Research Method (RON)	92 (Regular), 95 (Premium)
UAE	Research Method (RON)	91 (Special), 95 (Super), 98 (Ultra)
Saudi Arabia	Research Method (RON)	91 (Green), 95 (Red)
South Africa	Research Method (RON)	93, 95
Argentina	Research Method (RON)	95 (Super), 98 (Premium)
Chile	Research Method (RON)	93 (Regular), 95 (Extra), 97 (Super)

Different countries have their own characteristics in the way gasoline octane ratings are indicated and calculated, but they all revolve around the core indicator of knock resistance. Choosing the right gasoline is crucial for engine performance and longevity.

How to Know What Type of Gasoline to Use When Refueling in Different Countries?

When refueling in different countries, choosing the right type of gasoline is crucial. This not only affects vehicle performance but may also impact engine longevity.

Based on your vehicle needs and driving habits, making a reasonable choice of the appropriate type of gasoline can ensure smooth vehicle operation and extend its lifespan.

Suitability and Characteristics of Different Octane Gasoline for Vehicle Types

Octane Rating	Measurement Method	Suitable Vehicle Types	Characteristics
87	AKI	General vehicles	Suitable for daily driving, lower price
91	AKI	General vehicles, performance vehicles	Provides better performance and combustion efficiency
97-98	AKI	High-performance vehicles	Suitable for performance vehicles that require high octane
E25	AKI	Flexible fuel vehicles	Uses ethanol blended fuel, suitable for Brazil
E100	AKI	Flexible fuel vehicles	Uses ethanol blended fuel, suitable for Brazil
91	RON	General vehicles	Suitable for vehicles in Japan and Asia
92	RON	General vehicles	Suitable for vehicles in China and Asia
95	RON	High-performance vehicles	Provides higher performance and combustion efficiency
98	RON	High-performance vehicles	Suitable for performance vehicles that require high octane
100	RON	High-performance vehicles	Provides the highest performance and combustion efficiency

How to Choose the Right Gasoline

Improper use (such as using the wrong fuel) may not cause immediate serious damage, but long-term use can have negative effects on the vehicle. Therefore, it is very important to understand the correct type of fuel required for your vehicle.

1. Check the Owner’s Manual

The manual for each vehicle usually clearly states the recommended type of gasoline to use.

2. Consider the Engine Compression Ratio

Compression Ratio	Recommended Gasoline (AKI)	Recommended Gasoline (RON)
Below 8.5	87	92
Between 8.5 and 9.5	91	95
Above 9.5	97-98	98-100

3. Driving Needs

If you often engage in high-intensity driving (such as high-speed driving or frequent acceleration) or long-distance travel, choosing high-octane gasoline may help enhance performance and stability.

4. Operating Environment

In different environments (such as high-altitude areas), changes in air pressure and temperature can affect combustion efficiency, and adjustments to the type of gasoline used may be necessary.

Environmental Conditions	Recommended Gasoline Octane Rating	Explanation
High-altitude areas	92 or lower	As altitude increases, air density decreases, combustion efficiency decreases, and the risk of knocking decreases, so lower octane gasoline can be used. For every 1000 meters increase, the gasoline octane rating can be reduced by about 1 unit.
Low-temperature environment	95 or higher	In environments below -20°C, gasoline may become viscous, affecting vaporization and ignition. Using higher octane gasoline can improve ignition performance and reduce starting difficulties.
High-temperature environment	95 or higher	High temperatures may lead to increased fuel volatility, and using higher octane gasoline can prevent knocking and improve engine stability.
High-humidity environment	95 or higher	High humidity may lead to uneven fuel mixing, and using higher octane gasoline can improve combustion efficiency and reduce black smoke emissions.

Choosing the right type of gasoline not only depends on the technical requirements of the vehicle but also needs to consider the current environmental conditions. Adjusting the octane rating of gasoline used in different environments can effectively enhance engine performance and extend its lifespan.

Therefore, it is very important to understand the local environmental conditions and their impact on gasoline requirements before driving.

What to Do If You Don’t Know What Gasoline to Use? Is Using Higher Octane Gasoline Safer?

Not necessarily better; for low-compression engines, using gasoline with too high an octane rating may not bring significant performance improvements and may increase fuel costs.

Therefore, choosing the octane rating that suits your vehicle’s needs is the ideal approach.

If you are unsure what type of gasoline to use, you can first check the owner’s manual to understand the recommended octane rating. Using higher octane gasoline usually provides better knock resistance, but it may not be suitable for all vehicles.

Choose the appropriate fuel based on your vehicle type, engine compression ratio, and driving needs to ensure stable engine operation and extend its lifespan.