"Micro-tip spark plugs (Iridiums) were invented as a self-cleaning mechanism. As the current jumps the gap it takes the carbon along with it, thus the self-cleaning aspect. Iridium tips are best suited to do this as they can handle the current with tips as small as .03 and they will not wear away. Let's call the Iridiums the "RE" plugs.

Next up are the Platinum spark plugs. Nice, and better than copper plugs, but certainly not Iridiums. They are the "EQP" plugs and are what we call "FD" plugs. (Spark plugs do NOT go bad in the Renesis as often as people think. As has been stated, as long as the tip and ground strap are not worn so much that they increase the gap too much, they are fine and can be cleaned. Use a plastic-bristle brush and carb cleaner and they are as good as new. I have done this many times with my own plugs. This is axiomatic with spark plugs.) I have tried these plugs in my own engine and I noticed less throttle response and a duller exhaust note.

With an N/A Renesis engine, always use the Iridium plugs. Although it may seem cheaper to use the "FD" plugs, which are either the NGK BUR9EQ and BUR7EQ (which are copper plugs) or the BUR9EQP and BUR7EQPs (which are Platinum plugs), in the long run your performance will lack and you'll end up changing them often enough so as to make the cost equal. With greater grounding area available, the BURs will foul sooner than the REs. Even the EQPs are not quite up to the task of the Iridiums.

In our testing of spark plugs we have learned that with the BHR Ignition System the Iridiums last a LOT longer than do the EQPs (Platinum) and, most notably, the EQ (copper plugs)."