Spark plug gap - Why so big?
I was working on a friend's modified 2002 Z06 this weekend, and changing his plugs. He was having a miss and I found one fouled and one heavily carboned (#7).
When I checked gap they were between .055 and .058 on NGK TR55 plugs.
MTI did loads of headwork and he has headers / full exhaust all the bolt ons. He's made a best of 441 rwhp, so it's pretty heavy mods. I think he's running about 11.5:1 compression. Sorry I don't have the exacts, but from what he says that's pretty close.
Anyway... in the 2003 Cobras most guys like myself are running about .040 on the plugs (NGK TR6), and the modded guys over stock boost are running sometimes as low as .035 on the Denso Iridiums IT 20 or 22. Running a gap of .060 like you guys are from stock would never work. It would blow out way too easily.
So why such a large gap on the 'vettes? Don't you guys worry about blowout once you have heavy mods?
I put the new ones in at .045 (ACDelco was only available). The miss was cured, and I'm thinking he should go with Denso IT 20 at about .040.
Am I way off? Why or why not?
Thanks in advance.