NGK T6 Plugs Or TR55 Plugs?
12-29-2009, 08:53 AM
#21
I have always used whatever plugs came stock in my bolt on or cam only cars. I tried the NGK TR-55's in this car and they were fine.......for about 4000 miles. It then started to have an inconsistant high RPM miss which later went to a dead miss at all RPM's. Pulled the plug and it looked fine. Replaced it with a stock Delco plug and the miss went away. I'm going back to what GM recommends, AC Delco Iridium 41-110 at .040. Went iridium because I don't enjoy changing plugs on this car and the iridiums will last longer, not for any performance increase. Now I know NGK and Delco are somehow related but Delco and NGK just tell me they sometimes use the same plants. The deciding factor for me was putting a tr-55 next to a stock delco. The ground electrode sticks down farther, the center electrode sticks down farther and is fatter on the NGK. Does that make a real world difference, I don't know. I'll leave that up to the experts, but I've never had a stock plug give up on me in 4000 miles so I'm going back to Delco's. NGK tr-55 is what is recommended for your application and is highly endorsed by most on this board, I just didn't have good luck with it.
