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Spark Plugs

8K views 25 replies 15 participants last post by  Jeep Freedom 
#1 ·
Its about time i do my spark plugs and i was just getting everyone's opinion on which spark plugs are worth it i have a 05 GC Limited 5.7. All inputs are welcomed
 
#5 ·
OEM Champions, which the Hemi was designed to use, and CHampion is the #1 spark plug in NASCAR and F1.
 
#6 ·
I've heard to stick with OEM: Champion 570's. I have done them without issue.
 
#7 ·
Good afternoon,

MOPAR OEM or Champion 570's. Have used both and they perform equally well. The '05-'08 5.7L HEMI plugs are changed at 30K miles anyway. Only difference seems to be price: MOPAR = $4 ( :() and Champion 570 = $2 each :))).

Ready for my 4th set of plugs in 900 more miles (about 2.5 weeks' driving). Gap each plug to 0.043" and torque to 13 ft-lb.

One thing I do is tape each plug when it comes out and mark it with the cylinder # and F -or- R so I know where it came from later. You will see that the electrode areas of the MDS cylinder plugs look different from the non-MDS cylinder plugs. I also check the gap of each plug as they come out. Not to record, but to get a feel as to how much the gap has opened over the previous 30K miles. [From experience, it seems ~0.005-0.008" is normal on my 5.7L HEMI.]

Hope this helps. Enjoy your HEMI. :D
 
#8 ·
The OEM Mopars I believe are (the same as) Champion 570's, so no need to buy the plugs from a dealer.
 
#15 ·
Recommend you keep your old plugs.

FWIW, several other threads and forums have reports that the non-copper core plugs (e.g., platinum and iridium) are the cause of 5.7L HEMI engine performance irregularities (stalling and bucking) after ~5,000 miles following installation. IDK if this is true, but why upgrade to something that is changed out every 30K miles?

I am aware that other Jeep engines (e.g., 4.0L I-6, 4.7L V-8, and 6.1L HEMI) use other more sophisticated & longer-change-out spark plugs. However, I have never heard a technical explanation on why only the 5.7L HEMI takes copper core plugs every 30K miles.

Perhaps you've hit on an acceptable substitute for Champion 570's. Please keep us informed. In my case, it's a 30K miles changeout anyway to keep the Lifetime Limited Powertrain Warranty in force, so extended spark plug life is not an option.
 
#16 ·
I just installed a 2 step colder NGK set of 16 in my engine. Im feeling a difference :)
 
#17 ·
....and you have a 6.1L HEMI. Believe the OP has a 5.7L HEMI. They have different plug requirements:
The earlier 5.7L HEMI's use OEM P/N SPRE14MCC4 (Champion 570)
The VVT 5.7L HEMI's use OEM P/N SPLZFR5C11 (NGK)
The 6.1L HEMI's use OEM P/N SPLZTR5A13 (NGK Double-Platinum 4998)
 
#19 ·
I know walt, just wanted to throw in my 2cents. I do believe a few guys running the stock 6.1L plugs and have noticed a little more pick me up.
 
#23 ·
#24 ·
To measure a plug's spark efficiency, you need to monitor it actually firing in a cylinder. At Mich Tech Univ. they have such a setup in their lab for comparing plugs.
http://www.me.mtu.edu/researchAreas/aice/projects/SIImaging.html
We can report our test results concurrently.

From what I've read so far, it's not efficiency that is the issue. It's effective ignition timing and DTC's generated by the PCM. If one changes the inductance or capacitance of the secondary circuit, the voltage curve will change and therefore the breakdown of the dielectric that leads to spark arc across the electrodes.

I'm doing this out of general curiosity. Since the materials of construction among the 3 plugs are likely different, I assume some of the basic electrical parameters will be different also. Maybe not. That's the purpose of the experiment.

For my '08 5.7L HEMI, I will continue to use Champion 570's or OEM SPRE14MCC4, whichever is cheaper at the time. Changeout is 30K miles, irrespective of plug type. Jeep has 86,500 miles on it now and no plug issues; it would take some strong objective evidence for me to consider changing.
 
#25 ·
I ran the Walmart autolite ones from 60k-80k before my build and didn't feel any difference.... but now I am sticking to 570's
 
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