I bought these off EBay and was wondering if they have any effect to the stock motor?I heard that these are cold plugs.Will it harm the performance if I don't have SC or Turbo?Please help before I do something wrong.....

 

What's the heat range ? 6? If it's 6, then yes, tehy're a step colder and you may not run 100%.

Should have just got coppers.

 

SO I shouldn't bother putting them in?Anyone know how bad it can cause to my motor?

 

I used iridium plugs for about 6 months and they ended up fouling out causing black smoke out the tailpipe under acceleration. I swapped them out for ngk coppers and my car ran much better with no black smoke. I think they are a waste unless you are boosted.

 

same thing happens to me, ever since i installed my iridiums, when i downshift and gun it, a puff of black smoke comes out, i always thought that was normal. i guess i was wrong.