What Octane Rating of Gasoline Should Be Used for a Compression Ratio of 9.5?

[ReidFitz]

A compression ratio of 9.5 should use 95 octane gasoline. For engines with a compression ratio between 8.5 and 9.0, 95 octane gasoline is recommended. If the compression ratio is higher, a higher octane rating gasoline should be used. The compression ratio of an engine refers to the degree of gas compression, which is the ratio of the volume of gas before compression to the volume after compression. Generally, gasoline engines have a compression ratio between 6 and 10, while diesel engines typically have a compression ratio between 16 and 22. If an engine has a high compression ratio, the temperature that the gasoline-air mixture can reach after compression is also higher, resulting in greater energy release during operation and higher power output. Conversely, if the engine has a low compression ratio, the temperature that the mixture can reach after compression is lower, leading to less power output and smaller energy release, thus requiring a lower octane rating of gasoline.