Compression Ratio 13:1 - Should I Use 92 or 95 Octane Gasoline?

[ElleDella]

For a compression ratio of 13:1, 95 octane gasoline should be used. Engines with a compression ratio above 9 should use 95 octane gasoline - the higher the compression ratio, the higher the octane rating required. Below is relevant information about the relationship between compression ratio and gasoline octane ratings: The correlation between compression ratio and gasoline octane ratings: The primary basis for selecting gasoline octane ratings is the engine's compression ratio, because the air-fuel mixture generates heat during compression - the greater the cylinder pressure, the higher the temperature becomes. For example, engines with compression ratios below 8 can use 90 octane gasoline. Gasoline's anti-knock properties: After the air-fuel mixture is injected into the cylinder, the piston moves upward to compress the mixture. As pressure increases, temperature rises sharply. If the gasoline's anti-knock properties are insufficient at this point, premature combustion may occur before spark plug ignition, resulting in engine knocking. A car's compression ratio refers to the ratio between the cylinder's maximum volume at bottom dead center and minimum volume at top dead center during the compression stroke. Gasoline octane ratings represent the ratio between actual gasoline's anti-knock properties and those of standard gasoline. Higher octane ratings indicate stronger anti-knock performance.