What Octane Gasoline Should Be Used for a Compression Ratio of 9.8?

[SanCharles]

If it is a naturally aspirated engine, a compression ratio of 9.8 is relatively low, and 92 octane gasoline can be used. Some turbocharged engines also have a relatively low compression ratio, but the temperature and pressure inside the cylinders of turbocharged engines are higher during operation, making them very prone to knocking. Therefore, these turbocharged engines require the use of 95 octane gasoline. Additional Information: Knocking Concept: Knocking is an abnormal combustion phenomenon in the engine. During the compression stroke of the engine, the piston moves upward to compress the combustible mixture. At this time, due to the high temperature and pressure, the combustible mixture ignites spontaneously. The burning combustible mixture pushes the piston downward, while the piston is still moving upward, which can cause damage to the engine and reduce power while increasing fuel consumption. To avoid knocking, higher octane gasoline should be used, as this type of gasoline has a higher octane number and better stability.