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Old 10-26-2005, 07:45 PM   #21 (permalink)
klamathpro
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Default Re: Detonation vs. Pre-Ignition

Quote:
Originally Posted by Import Power
Your summation is incorrect. One of the main jobs of a sparkplug aside from igniting the mixture is HEAT REMOVAL from the chamber. It is this HEAT (along with pressure) in the chamber that causes detonation. The colder the plug the more heat (and faster) the plug can pull out of the chamber and move it to the cooling system for removal. This chamber cooling is what colder plugs are all about. And this is why colder plugs lower chances of pre-ignition detonation induced by a heat spot caused by the plug itself.


Colder plugs also pull heat off thier tip faster which does help pre ignition as well.
Mind telling me how a colder plug can "pull heat" away and into the cooling system? Colder plugs simply eliminate the plug from being a source of heat, not draw heat away or remove heat. The spark plug has many points of heat spot potential and that is why a colder plug works well in preventing pre-ignition and detonation induced pre-ignition.

What I was saying was the fact that true detonation occurs away from dead center usually rules out the plug as being the main culprit. This is because the gases have moved away from the center of the chamber after the explosion. However that hot plug could pre-ignite the next cycle which would occur at or near the chamber's dead center. Which is why I never noticed a reduction in knock by going to colder plugs because our knock sensors detect true detonation and not pre-ignition. Detonation simply occurs away from the spark plug. As quoted under pre-ignition: "A glowing spot somewhere in the chamber is the most likely point for pre-ignition to occur. It is very conceivable that if you have something glowing, like a spark plug tip or a carbon ember, it could ignite the charge while the piston is very early in the compression stoke." Which is where a colder plug benefits.

I'm not saying there isn't a benefit to having colder plugs, heck I bought two sets off of you. I'm saying that colder plugs cannot draw heat away and cannot cure knock problems. Retarding timing reduces knock. But colder plugs sure help with pre-ignition and detonation induced pre-ignition and you can count on me buying them again in the future.
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Last edited by klamathpro : 10-26-2005 at 07:56 PM.
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