Another spark plug thread (copper vs iridium)

[blabarre]

So I have a 2011 5.7 hemi with 113k miles. I spent several hours last night researching spark plugs through the various threads out there. Didn’t really see anything recent about this so I thought I’d post this. I have been reading about the 2009-2013 trucks require the copper plugs because in 2014 they upgraded coil packs even though the part numbers for the packs are the same, but the 2014-present 4th gens use iridiums. Of course I’d prefer the iridiums for the longevity but I hear these hemis are very peculiar when I comes to plugs.

Also have seen on rock autos website that for the ngk copper plugs, that it has a footnote that states fca says that the iridiums are acceptable now to use... my question I guess, can I use the ngk iridiums ix? Seems like there have been a few people running them with no misfires..


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[Doodoo972]

Hy Blabarre, I'm in the same case with my 2012. The last car owner give me a set of iridium plugs but I couldn't find a clear answer: is my truck will run fine with these iridium ?
So I bought a set of copper and put it in and I still have the iridium set... maybe I could use it the next time?

 

[crash68]

Thought I remembered reading that you needed to change the coils if you wanted to run iridium plugs if your truck originally came with copper plugs.
I bet @Tach_tech would know the answers to your query

 

[blabarre]

Thought I remembered reading that you needed to change the coils if you wanted to run iridium plugs if your truck originally came with copper plugs.
I bet @Tach_tech would know the answers to your query

I’ve been reading the same but I’ve seen where some people with 2011s have run the ngk iridium ix without changing the coils and they said they had no issues. Was hoping to see if others had experience with this.


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[Wild one]

I’ve been reading the same but I’ve seen where some people with 2011s have run the ngk iridium ix without changing the coils and they said they had no issues. Was hoping to see if others had experience with this.


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I'd close up the gap slightly. They call for .043" gap on the trucks originally equipped with iridium plugs,if you're running them on a pre-iridium plug equipped truck,i'd close the gap up to probably .039"/.040". The bigger the gap,the more coil output and saturation time needed to generate a stronger spark to jump that gap,by closing up the plug gap,you take some of the load off the coils,and the older coils will have enough juice to generate a good spark

 

[Tach_tech]

So to add more confusion to this. I spent some time going through the service manuals/parts info and the coils don’t have a part number change until 2016. In 2013 there is two listings for plugs, older part number SPLZFR5C11 which is used in older than 2013 as well, and the newer part number SP143877AA which is 2013 and newer.

I always thought both the plugs/coils changed 2013/2014 to the newer coils and iridium plugs but now I’m not sure of the coils.

Realistically you could probably run either and you shouldn’t really have any issues.

 

[DAK2]

Actually the plug you want is the NGK92145 (LZFR5CI-11) not the iridium IX. I have the 92145 in my "11". I did not change coils.

 

[Doodoo972]

Thanks DAK2, so if it worked on your "11" without changing the coils it will do fine on my "12" ! Rather be sure before changing the plugs because it takes a significant amount of time and patience.

 

[blabarre]

Actually the plug you want is the NGK92145 (LZFR5CI-11) not the iridium IX. I have the 92145 in my "11". I did not change coils.

That’s awesome. Did you have to gap them at all? And didn’t change coils?


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[DAK2]

Standard gap and no the coils are the ones that came on the"11". I never run with MDS on.

 

[blabarre]

Standard gap and no the coils are the ones that came on the"11". I never run with MDS on.

Do you have a programmer? Is that how you run without mds? Also, would I need to not run mds in order to run the iridium plugs?


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[DAK2]

No I don't have a programmer, I either set ERS 5 or tow haul mode, as that shuts MDS off. I have run that way since about a month after I bought the truck in "11". I have a flowmaster 40 delta flow muffler on it and it sounded like S**t running on 4 cyls. I don't see any reason why you can't run with MDS on it's just my option not to.

 

[gears49]

Just to clarify, mine is a 2017 Ram with the Hemi. Do I understand correctly that I have Iridium plugs from the factory? If so, at what interval is it recommended to change them? Thanks in advance for your answer.

 

[blabarre]

Just to clarify, mine is a 2017 Ram with the Hemi. Do I understand correctly that I have Iridium plugs from the factory? If so, at what interval is it recommended to change them? Thanks in advance for your answer.

From everything I’ve read, yours come with the iridium plugs and it’s 100k interval.


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