Compression influence on plug choice?

[Dan355]

Basically wondering if you would use different plugs for your compression ratio? Or doesnt it matter? What about in a blown application, Different plugs again?

Cheers

[cohn]

no the plugs shouldn't change for different compression ratio's as a direct influence, the only difference in plugs would be heat range, a plug works optimum at a certain temperature, and the plugs temperature is determined by the distance between the centre electrode to the pocelin and tothe thread of the plug, this will determine how fast the plug disapates heat.
But in saying that, when the compression ratio is change for power appplications, then the combustion temperatures wiull be different anyways, so yes in that fact.

[Dan355]

no the plugs shouldn't change for different compression ratio's as a direct influence, the only difference in plugs would be heat range, a plug works optimum at a certain temperature, and the plugs temperature is determined by the distance between the centre electrode to the pocelin and tothe thread of the plug, this will determine how fast the plug disapates heat.
But in saying that, when the compression ratio is change for power appplications, then the combustion temperatures wiull be different anyways, so yes in that fact.

Thanks thats what i thought.........Im going to get new plugs tomorrow just wondering what would be best. If there all the same and dont need a specific type then thats all i need to know.

Cheers

[immortality]

lets look at this from another angle, pre ignition/detonation comes about from compression Vs heat Vs time. so if you increase the compression then it will take less time & heat before you reach the pre ignition/ detonation phase. if you have increased the compression by only a small amount i wouldn't worry about changing the plugs, ifyou have gone up by more then a little bit i'd suggest going one or two steps lower in the heat range and then monitor the plugs for fouling etc.