How well do these perform? I heard from ebay, they can give you 34+ HP(which I relize is a joke) but what can they do, and what do they do/what are they?
-Nick
I have never run them but I have found out a couple things. They are good with boost or juice. They are harder than copper or platinum. They offer the benefits of a platinum plug, but they are a better conductor, last longer up to 250,000 miles, and are expensive as hell. Last price I saw was 11.99 each
You can check out the Denso website for more information. In a nutshell, they are a low resistance plug with a very fine tip on them. End result, it takes less voltage to fire the plug and the fine tip creates a concentrated spark. Supposedly, it offers more consistent and hotter spark than even a platinum plug. In turn, it may offer a little more horsepower, little better idle quality, etc. I have a set in my '01 Crown Victoria...replaced my platinums. $12 a plug X 8 plugs...expensive. I didn't notice a difference except for a very slight difference in idle quality. I'm not sure if it was worth all that money. I can think of more productive ways to spend $100.
Side note: I am not sure if these are recommended for "hot" aftermarket ignition systems like those offered by MSD, Jacobs, and the like. The directions on my Jacobs Pro-Street ignition specifically says to use a conventional copper-core plug because it will quickly burn the tips off a platinum or split-fire plug.
something that comes to mind with the "side note" above. these plugs are supposed to be great for boosted and juiced applications, as mentioned. i dont know of many folks using juice or boost that done use an aftermarket ignition.
so i would read up on both ends if both apply.
the cool thing about iridium is that it is super hard and conducts well, so it should last longer (more like platinum), but with good conductivity (more like copper; platinum doesnt conduct worth a poo compared to copper). so iridium should have the longevity of harder materials with the conductivity of shorter lived materials.
i would not leave plugs in anywhere near the intervals suggested. it might be nice on a camaro or something with inaccessable plugs, but the 302 plugs take ten minutes to swap anyhow.
just my two cents.