Detonation

Pre-ignition is similar to detonation, but is caused when the air/fuel mixture ignites prior to the spark ignition.

Detonation refers to an uncontrolled combustion, which elapses much more rapidly and which generates a shorter-lasting but more powerful pressure on the piston. Detonation can also be caused when the pressure of an expanding (spark plug initiated) flame front causes combustion to begin separately in other areas of the combustion chamber.

Pre-ignition is similar to detonation, but is caused when the air/fuel mixture ignites prior to the spark ignition. Pre-ignition, like detonation, can be caused by excessively high temperature and/or pressure generated during the compression stroke.

• High boost

See also: http://www.streetrodstuff.com/Articles/Engine/Detonation/ http://en.wikipedia.org/wiki/Engine_knocking

Typically, when air and fuel burn in the combustion chamber, the burn is a gradual process, elapsing over a period of a few milliseconds as the flame front spreads from the spark plug which initiated the combustion. Under ideal conditions, the flame front expands uniformly, so that the combustion process exerts a continuous pressure on the piston during the piston’s down-stroke, resulting in a smooth strong twist on the crankshaft.

Detonation refers to an uncontrolled combustion, which elapses much more rapidly and which generates a shorter-lasting but more powerful pressure on the piston. Detonation can also be caused when the pressure of an expanding (spark plug initiated) flame front causes combustion to begin separately in other areas of the combustion chamber. Pre-ignition, which is similar to detonation, can be caused when the air/fuel mixture ignites prior to the spark ignition, due to abnormally high temperature and/or pressure generated during the compression stroke.

The increased heat and pressure of detonation and pre-ignition are be very destructive, particularly to the piston heads and ring lands, making this a leading cause of engine failure in high-performance engines.

• Low octane?
• Lean AFR
• High boost

Typically, when air and fuel burn in the combustion chamber, the burn is a gradual process, elapsing over a period of a few milliseconds as the flame front spreads from the spark plug which ignited it. Under ideal conditions, the combustion process exerts a continuous pressure on the piston during the piston’s down-stroke, which results in a smooth strong twist on the crankshaft.

Detonation refers to an uncontrolled combustion, which elapses much more rapidly and which generates a shorter-lasting but more powerful pressure on the piston. The increased heat and pressure of detonation can be very destructive, particularly to the piston heads, and is a leading cause of engine failure in high-performance engines.

Factors contributing to detonation include:

• High IAT (Intake Air Temperature)
• Excessive timing
• Low octane?