exracer28

I was working on a 30k C6Z06 and 5 0f the plugs lost the Iridium tip. Street car without any track use and the gap on the 3 plugs that still have the tip is 0.040 but the 5 without the tip have a 0.080 gap. I thought that the Iridium tip plugs were reported to be more durable but I think that I will be looking for a non-Iridium plug. I don't know if this is a production issue or design so replacement will be a non AC plug. I do have pictures if anyone wants me to email the pictures just let me know. Now I am going to pull the plugs on my other cars and check them.

C7/Z06 Man

Maybe try a Denso Iridium or NGK Iridium. I think one of those companies make the plug for GM but could be wrong so If you find out than try the other companies first and another thing to keep in mind is that GM's spec. maybe different then the companies own plug for the car.

You might also want to consider trying a step colder plug.

CI GS

I've seen this happen before with GM Iridium plugs, but only when I was using a big hit of N2O. Have to say that I didn't notice any difference in performance though. Just found a huge gap from the nubs being gone off the ground strap when I pulled the plugs to read them. The Densos are what the big power turbo guys use. But, they're not cheap!