Use $7 plugs or .99¢ plugs w/ EDIS

[dr.occa]

i'd like to get the Megajolt Lite Jr community's thoughts on this "debate".

MSD states that the iridium & platinum plugs are poorer than copper when conducting electricity and that the MSD units will fire the 99¢ plugs up equal to their more expensive counter parts, is this also the case for MEGAJOLT?

Copper is second only to silver when it comes to conducting electricity and silver being at the top of the list.

[brentp]

Much debate on this topic.

As I understand, the stated benefits of the iridium plug are that the ultra-hard nature of this material allows for the creation of a sharp and durable spark plug tip, which presents an easier path for the spark energy to jump. Think of a lightning rod on a building. The rationale is to improve the chances of firing in challenging combustion chamber conditions, such as high boost / compression, anti-fouling, etc.

The difference in electrical conductivity is small between the two:

Copper Electrical resistivity (20 °C) 16.78 nΩ·m
Iridium Electrical resistivity (20 °C) 47.1 n Ω·m

That's in nano-ohms.

Source, wikipedia.

[Oliver Sedlacek]

Resistivity of the electrode material is pretty much irrelevant, as there will be probably 1000 ohms of suppression resistance in the HT circuit. The important material property of the plug electrode is its thermal behaviour and its durability in the harsh conditions in the combustion chamber.