I installed the Ngk bkr6e plugs on my stock 06 cobalt ss sc on friday and gapped them at
.040(edited). The car Idles a lot smoother and so far the irratic idle with the stock plugs hasnt reared it ugly ass head yet. The car sounds a lot smoother throught the rpm range when you get on it and it is a lot easier to take off in first gear. I have switched to ngk v power plugs in my last 3 vehicles and each time they ran smoother. The LS1 had a lot of spark knock with the stock plugs and the ngk's cured it and my z71 never had any issues with them.

 

I did the same thing to my car and have had a similar experiance.

 

Is the .40 too fat? or does that sound right to everyone. I wanted to switch mine out and was not sure how far to gap them?

 

My manual said the stock gap is .039, so that's what I set mine to. I have some BKR7E plugs to put in when I up the boost, those will be set much tighter, like .028-.030.

 

So the BKR6E at .40 is good. I guess thats what I'll go for then.

 

Well techically it should be .040 but yea it will work fine.

 

.040 is what I measured the stock plugs at with the fold out feeler gauge. The new ones were gapped at .035 out of the box and I changed them to match the stock plugs.