I used NGK Iridiums for a few hundred miles but car would backfire/pop WOT from time to time so I went back to Greddy ISO 8 racing plugs which are F---- $80.00 but have been great so far, I wonder if the METH keeps em clean or is bad for em, anyone have a comparable IRDIUM plug that is close to Greddy's but cheaper?

 

yep..thats the weakness of iridium is that they are hard to gap. I did gap mine but slowly and with a feeler gauge to get em to .032. Either way im gonna switch to the "8" NGK Copper Plugs when I get retuned next week for a 3bar map and race gas.

 

Does NGK make a heatrange 8 plug with resistor? I have not been able to track down any.

But the NGK Heatrange 8 Iridium plugs seem to be the way to go

 

I've been running Denso IK24s in my car for over two years now (installed when the Comptech SC/AC was installed). I've had no issues at all and the eight plug checks have shown nothing out of the ordinary - which reminds me another check is due.

Here's a little excerpt from a pdf that I downloaded from AEM's website:

The spark plug gap on forced induction engines should be reduced REGARDLESS of the type of ignition system. We have read many instruction manuals for aftermarket ignition systems that recommend that the plug gap be opened up for better flame propagation. Although this recommendation may have had some merit when vehicles had carburetors, it does not apply to modern engines with electronic engine management systems. The smaller gap on forced-induction engines requires less spark energy to arc across the ground and the electrode and has a lesser tendency to misfire under the extreme pressures of a racing engine combustion chamber. Also there are spark plugs made with exotic fine wire highly conductive center electrodes that require less energy to fire such as the Denso Iridium that are well suited to racing conditions. The following is a chart of gap sizes for various engines on gasoline:

Naturally Aspirated up to 11.0:1 CR 1.1mm (.044

 

nice find

 

I used to have my ngk iridium's gapped to .028 and never had a problem. I decided to change my gap to .022 since im running 28 psi and now it runs funny. Im not sure if its the gap change causing it or the retuning and new o2 we tuned off of that could be bad.

 

well which part or what number are the iridium used for boosted s2000?
Stefce

 

You can look here for starters:

http://www.densoproducts.com/resultsSearch...CFRKAxgod43cC3w