Private Pilot Licence · Practice

The key difference between detonation and pre-ignition is:

• A.Detonation only occurs in jet engines under very high combustion temperatures and pressures
• B.They describe the same combustion event — both cause the same knock and are remedied identically
• C.Pre-ignition is harmless and produces no abnormal pressure or temperature in the cylinder
• D.Detonation = uncontrolled combustion AFTER the spark; pre-ignition = the mixture ignites BEFORE the spark (a hot spot)