The limit to the amount of supercharging that can be applied is the ______ rise caused by compressing the mixture and the liability to cause ______.

• A. Humidity, Corrosion
• B. Volume, Pre-ignition
• C. Temperature, Detonation
• D. Pressure, Knocking

Answer: (C)

When you boost an engine, compressing the intake air raises its temperature as well as its pressure. That hotter charge is more prone to abnormal combustion, so pushing the boost too far increases the likelihood of detonation. Detonation is the dangerous, explosive combustion that can damage the engine, so the practical limit to supercharging is the temperature rise from compression and the risk of detonation. Humidity and pure pressure considerations aren’t the primary limiting factors in this sense, and while volume changes with compression occur, they don’t set the critical safety boundary like temperature rise and detonation do.