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2026. 6. 30. 작업

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What are the various causes of preignition / detonation?

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Most of my knowledge comes from turbo engines. Detonation or preignition is caused by the air/fuel mixture igniting before the spark plug fires. The mixture is typically ignited by a hot spot either in the head, or on some carbon deposits. Turbo and superchargers are more likely to detonate, because of the higher pressure. There is more volume of air/fuel mixture in the cylinder, which when ignited, causes more pressure and heat. Ways to avoid detonation: Turbo/supercharged engines run rich when in boost, around 11:1. The unburnt fuel help absorb some of the heat. Higher octane fuel is more detonation resistant. Alcohol injection - basically raises the octane. Water injection - the water helps absorb heat. Cool the intake charge - cold air intake, intercooler, nitrous. These will give you a denser air charge, and will require more fuel. Colder spark plugs Reshape combustion chamber - make sure everything is smooth. Small parts (corners, edges)heat easier. On turbo/supercharged engines,