[mwebb]

as a long time scope guy , i will say most
(but not all)
of the info in this thread is pure nonsense

what is true is that copper plugs do not last as long as the others
unless
the engine is using a wee bit of oil
then
all three last about the same amount of use / miles

platinum plugs tend to foul easier and stay fouled once fouled
iridium are not much better

copper is the cheapest and electrically the best of the lot , but

the spark plug that was designed for the system by the engineers who designed the system is always the best choice for that particular system

use the OEM recommended brand and part # ONLY for best results

if any one of you can post a scope waveform showing any inaccuracy in this post
do it now -
allow me to save you the trouble
there is no waveform that will invalidate this post

stop this nonsense - use the OEM recommended spark plugs only.
there is no super plug , only snake oil .

or spend the dollars , acquire the skill and learn about ignition , then with your new skills and equipment , out engineer the engineers who designed your system - rots a ruck with that .









the last image shows a "bad " secondary spark waveform 1st caused by leaking valve , 2nd secondary spark waveform is a "good" waveform ,2 cylinders of 8 culled from a much larger file using a high resolution scope .

you can not fool an ignition scope
there are no better spark plugs than those the system was designed around

do not attempt to out engineer the engineers
unless you enjoy chasing your own butt .