No, the RXXXX series NGK plugs are "racing plugs" and all non resistor plugs. I do run the R5671A-10 in my TA car and they work great. I use the R5671A-8 in my street car and they work good as well and I have no radio interference. I have heard the R series can cause interference with some radar detectors (though mine works fine).

Yeah you are quoting stock numbers which I'm unfamiliar with but I think sparkplugs.com can interchange the numbers for you.

 

Could you elaborate this abit? I was of the opposite understanding.
The iridiums have a much thinner electrode and its area for transfering the current/spark is much smaller thus making the spark more intensive for a given electrical tension. The electrode in iridium plugs can be thin due to the durability of the iridium compared to copper.

Problem with plugs overall during high flow E85 conditions are that the spark is too weak for good ignition. In my mind, (without any reference experience) it would be better to keep the thinner electrode.
However, the reasons I have heard for people going copper is that they are easy to regap (to smaller gaps), and thus compensating some for the inferior sparkcapacity of the stock ignitionsystem in their high hp setup. (Not talking about the S2000)

 

^^If I had problems with the 7173's because they were non resistor plugs, wont I have problems with these too? I had spark blowout gapped to .023", rough idle and driving blips with the 7173's. Will I have the same problems with the 4554's? They are the same, 4554 is the R5671A-8. I went back to the BKR8EIX iridiums gapped at .030" and all the problems went away but these are resistor plugs.

 

Everywhere I read when I do a search for "iridium or copper spark plugs for best spark", they all say the coppers will generate the best spark. I'm not too sure on what to believe though.

Maybe someone that knows more than I do can comment on what would be better for e85 and 700+ whp, copper or iridium? I've also heard stories of people breaking off the tips of the iridium NGK plugs with high horsepower setups but I dont know how credible that is.

 

I think we all need to find and always use the best resistor plug and stay away from the non resistor types.

This is some good info from NGK. http://www.ngksparkplugs.com/techinfo/spar...faqresistor.asp

With that said, which resistor 8 plug is the best for our car and 700+ whp?

 

I would def. make sure the plugs were resistorplugs. Your problems are pretty similar to those described here:
http://www.ngksparkplugs.com/techinfo/spar...faqresistor.asp
I guess the same problems would appear on any other non-resistor plug.

Again, I do not have experience on this subject more than trying a few different resistor coppers and E85 and then moving to the bkr8eix. The coppers I tried were slightly gap-changed and did OK, but the iridiums just did better.

Edit: Lol, you beat me to it with the link.

 

I have also heard about the problems with breaking platinums or iridiums. The 2 tuners I have spoken to about it, both claims the breaks happened during tuning conditions. The iridiums have improved over time aswell from what I have heard.

Just thinking from a rational perspective, I am guessing that a thin electrode plug with a suitable gap (Do not ask me what "THE gap to have" is at those conditions) would work best. Pretty much basic physics.

Hopefully someone from full Blown or similar can chime in here, think they did some nasty setup with their dual walbro hanger and E85.

 

Actually regardless of the tip size the arc will only be between the very sharp corners of the electrode. The only advantage to iridium plugs is longevity. There is no way having a non resistor plug would cause misfiring. Sounds like you might be running to rich? I can't really think of a good reason you would have had a problem with those plugs that was solved (only?) by changing plugs to iridiums... I run non resistor plugs in both my cars like I said and my TA car runs on strait ethanol (which would only misfire worse) and it never misses.

Knock or detonation can break the tip off an iridium plug, I've seen it on dozens of cars.

 

If you are worried about a "hot" spark, upgrade your ignition.

The plugs you are running are fine. I ran those same plugs on 100% ethanol with no problems at all.

I've seen plenty of issues with non resistor, copper plugs, to stay far away from them.

You aren't going to get a solid answer on this topic of (this plug vs. this plug), everyone has their preference.

 

I'm not buying the electrical interference from a non resistor plug causing problems with anything but your radio or radar detector (i'm really not even buying the radio). I have 4 separate logging/control modules on my car and a beacon and have NEVER even had a glitch. They all run on a CAN bus which is notoriously susceptible to noise. That said I posted a part number for a 8 heat range copper plug with a resistor above