I tried doing a search regarding colder plugs and i got a million results, but they where all related to colder plugs when running nitrous or forced induction. From everything i have seen it doesn't seem like n/a guys change there plugs from the stock heat range, im wondering if there is a point when you are supposed to. Do they go to a colder plug with a more built engine? i have slightly higher comp pistons in mine and head work. The reason im asking is because im getting a little bit of detonation but its only between 4000-4500 but before that and after that to 5700 its fine, but my a/f ratio seems fine (but it is off the stock sensors because i don't have a wide band) and so does my timing, my iat's are a little high but at this point i don't really have any way of lowering them. i do have a exhaust leak by the header but i wouldn't think that would cause detonation, even though the detonation is comming from the bank where the leak is. Im wondering if i need to go to a colder plug or if i should be looking somewhere else. I ran some log files and

 

Bump!

 

i dont think colder plugs should be used on n/a. i have went to a bunch of plugs. iridiums and all. i wound up going back to the good ol tr55's and have had the best luck. i am running tr6 but i am running the juice to.

 

and it looks to me like one slow 02 sensor to.

 

I was taught that the rule of thumb was to go a step colder per every 100HP you add. My problem with that is from the 4.8's 270hp to the LS2's 400hp, the plugs are the same. It certainly will not hurt to go with a colder plug but I doubt it will cure your problem. A leak in the exhaust system "should" cause an o2 sensor to read lean which "should" in turn tell the pcm to add more fuel.

Your LT trims are equal at 3.9% which suggests that your exhaust leak isn't an issue. You're slightly lean, so I'd suggest trying to adjust your fuel tables to put you in -2 to 0 LT trim range. Hope this helps, good luck.

 

the one on bank 1? which bank is passenger side? that's the side of the engine my detonation seems to be comming from...i can tell its definately only comming from one side maybe only one cylinder of the engine

 

The other thing that i was thinking was going to a 180 stat instead of the 195, my short term fuel trims at normal driving are like -1.3 on each side.. would a colder thermostat help at all? Also why would the pinging only be in a 500 rpm range? maybe its a rattle im hearing but i highly doubt it, has anyone ever had a leak that sounds like pinging... because i have never heard one that does

 

also if i had o2 sensors that where slow what kind of problems could that cause? (they do have 90k on the sensors)

 

ok. I have been searching around for what people have done to solve detonation and i saw a member make this suggestion. He suggested going to a 180 stat, and then he also said to decrease the plug gap by .015 and maybe go to a step colder plug. What do you guys think? it seems like my a/f and timing is right so im thinking this might remedy the problem, the detonation im getting is pretty light

 

i would throw in some tr55 and leave them gapped at .50 like they come. the 02 sensor that is slow is the rear 02 pass side.yay at 199 i would go to a cooler stat. a 180 is going to run near 190. a 160 is going to run near 180.