detonation?

[Anaema]

anyone know anything about what affects detonation? i know there are alot different factors, but i dont know how each one affects detonation, and i would like to know.

 

[Peewee]

Fuel burning too hot is what causes this.
Effects are that it can melt alloy in extreme cases, otherwise just destroy pistons/head gaskets.

Most common cause is running too lean, usually from dirty injectors or a fuel pump gone bad (or running too much boost)

Other causes are old/poor fuel with poor octane rating.
Fuel too hot.

 

[MWP]

You forgot the all important ignition timing Peewee.
Having the ignition too far advanced is the most common cause on NA cars.

 

[Toysrme]

Incorrect ignition timing, incorrect cam timing, incorrect compression, lean conditions, hot charge temepratures, hot fuel system temperatures, hot combustion chamber temps, carbon buildup, incorrect spark plug heat range.


In a nutshell... Sparking too soon, artificially high compression, high charge, fuel, or temps of anything inside the chamber that the atomized fuel touches.

 

[Anaema]

ok, i think i understand all of that, except for how the cam timing causes detonation.

 

[Toysrme]

Peak effective compression ratio, and combustion temperatures change. Also, some vehicles have a cam driven distributor, or ignition system - which is self explainitory.

 

[Anaema]

well, i read something on the Internet(or maybe it was a Car and Driver article), but it said that holding the intake valve open a little bit toward the beggining of the compression stroke can... and now i just forgot the rest of it. anyway, it was a little along those lines.