Iridium Plugs - ZR-1 Net Registry Forums

jss06c6 · 10-31-2020

This has been discussed in other posts, but wanted to add some pics and history. My '91 is ported, full SW exhaust (headers to tips) and tuned.

I installed NGK TR7ix plugs gapped at .050" about 2,500 miles ago. Had dead coil, so replaced it. Wires were good. Had a slight, but noticeable stumble at low rpm acceleration. Decided to pull plugs. What I found shocked me. Only 2 of the 8 plugs remained at .050. Others were about .058. However #7 and #8 were .068! As others have indicated, batch fire and iridium don't seem to like one another. Moved to NGK 4177 (TR6) copper core. Gapped at .045".

Engine is back to 100%. Picture of #7 attached..20201030_183430.jpg

Sent from my SM-G950U using ZR-1 Net Registry mobile app

10-31-2020	#1
jss06c6 Join Date: Aug 2015 Location: Magnolia, Texas Posts: 884	Iridium Plugs This has been discussed in other posts, but wanted to add some pics and history. My '91 is ported, full SW exhaust (headers to tips) and tuned. I installed NGK TR7ix plugs gapped at .050" about 2,500 miles ago. Had dead coil, so replaced it. Wires were good. Had a slight, but noticeable stumble at low rpm acceleration. Decided to pull plugs. What I found shocked me. Only 2 of the 8 plugs remained at .050. Others were about .058. However #7 and #8 were .068! As others have indicated, batch fire and iridium don't seem to like one another. Moved to NGK 4177 (TR6) copper core. Gapped at .045". Engine is back to 100%. Picture of #7 attached..20201030_183430.jpg Sent from my SM-G950U using ZR-1 Net Registry mobile app