I have had Denso IT-22's in for about 1,000 miles now and i checked #5 and #3 yesterday. The electrode's were brownish, the porcelain white (not chalky or anything), and the base blackish. I then got out my old TR6's and they looked pretty similar. Then the stock plug's and they looked a little different, the electrode was similar but the porchlain had a slight brownish color, and the base blacker than the other two. I compared these because i was concerned about the white porchlain on the Denso's. The truck idles fine, runs strong, and the plug's have no sort of visible deposits on them. I think i'll Dyno soon and see what it tells. I have about all the bolt-on mod's including header's/cat's, #6 pulley, and Superchip. If anyone has a picture of what's considered a good burning Denso IT-22 that would be interesting to see. (I gotta get a digital camera, sorry no pic's)

 

I don't know if you will see much on the dyno. The Denso's do hold up to a lot of abuse and high boost levels.

 

John, I pulled a couple last week on my truck. Just like you described, except 20k miles.

I did notice that they had opened up a little. .003" from where I set them.

 

Here are plug readings from Denso but they don't show the Iridiums :

http://www.densoiridium.com/howtoreadusedplugs.php

Dan

 

LOVE MINE
408 rwhp and not a problem,only question how often o you change them??

 

The time to read a plug is IMMEDIATELY after a full power pass, not after driving back to pits or around town. This is especially true with blowers since cylinder pressures are much higher under boost. Reading plugs is also difficult with octane boosters and/or unleaded fuels.