View Single Post
      01-24-2011, 09:04 PM   #67
Ilma
Colonel
Canada
181
Rep
2,840
Posts

Drives: 2008 135i
Join Date: Nov 2008
Location: Mississauga

iTrader: (0)

Quote:
Originally Posted by COBB Tuning View Post
As well as different types of actual events that get covered under the "knock" moniker. Knock and pre-ignition are two very different things

Best regards,
Lance
KEY DEFINITIONS
Detonation: Detonation is the spontaneous combustion of the end-gas (remaining fuel/air mixture) in the chamber. It always occurs after normal combustion is initiated by the spark plug. The initial combustion at the spark plug is followed by a normal combustion burn. For some reason, likely heat and pressure, the end gas in the chamber spontaneously combusts. The key point here is that detonation occurs after you have initiated the normal combustion with the spark plug.

Pre-ignition: Pre-ignition is defined as the ignition of the mixture prior to the spark plug firing. Anytime something causes the mixture in the chamber to ignite prior to the spark plug event it is classified as pre-ignition.

The two are completely different and abnormal phenomenon.
Appreciate 0