How would napa have counterfeit plugs? This just doesn't make sense to me.The one in the pic above looks like a counterfeit? The numbers are hard to read an off-center. If I remember right that was one of the signs. I had about 4 sets that looked just like the ones you show off-center numbers and just didn't look right. I threw them out bought new ones and checked each one before I left the store with new ones. Not saying this is your case suggestion only. Need to cover myself don't want the misinformation police to call me out.
This sled is modified with a silber turbo currently at 5psi. I was not boosting heavy at the time and these plugs never saw any det. I did not have them in long enough to put them through any torture. As i mentioned with mine, my old plugs have withstood a bunch of boost (up to 10psi) and several incidents of det on hard wot climbs. I had to put them back in on the hill and they are still going strong once again. Its poor workmanship imo.Are all the failures on modified sleds? Just asking because detonation can break plugs for sure.
In theory its just subject to fouling more so than the projected electrode. That's the only difference.Bosch plugs have historically been pretty good, and I've never had an issue with the ones I've run. Unfortunately, while they make them in the correct size, they don't make them cold enough: seems they only make them in heat ranges appropriate for four-strokes. Not sure about Denso. They cross-references the IW27 to the BP9ES, and it'd probably work, but it's got a non-projected electrode. I can't find a projector-tip plug in the right heat range from them either. Can't think of anything a non-projector plug would hurt, but it's possible you'd lose performance.
except when it happens to 5 different local sleds from stock to piped to turbo? (Running NGK plugs)its's not the spark plugs..
it is DETO!! Period! Need more octane!!
Or a different head~