Good Spark Plugs for a 5.7L Hemi??

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64 SRT8 Dart

64 SRT8 Dart

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Hey everyone, I'm going to attempt a complete tune-up on our 2006 Jeep Commander with the 5.7L Hemi. Has almost 82,000mi on it.
Anyone have any ideas about a good spark plug for the 5.7? I want better power and mpg with em.
Also, if anyone knows of any makers of performance mods :burnout: (coil packs, wires, etc, etc), that could be done I would appreciate it!
Let's all keep in mind that my wife drives this to work every day:angel8:
 
I would try out TORQUE MASTER..I used them in 1998 for the first time. I have used them in many many applications since. They are what the E3's and other want to be..they actually hold the patent on the plug...Give a call or email them ... http://www.extremespark.com/
 
Spark plugs aren't going to do much but just keep the engine running smoothly. At most it pick up a few HP from a special plug.

I would just gap the new plugs a little tighter--.050 is good and buy new plug wires--that is a biggie, wires wear out. The plug fires so many times a second that a few misses you never feel but its there.
 
I would go NGK's. I think there is a thread on this in the hemi swap section. As far as mods, MSD makes coils, i am sure predator has ecu/tuners for it. I would look into a cold air for a srt8 jeep, it may fit with a different throttle body boot. Google search headers for it, exhaust is supposed to help the hemis a ton. That is at least a start...

Joe
 
Considering Chrysler recommends plug changes every 30,000 Miles, I think you're doing really well to get 82K out of yours.

The service manual specifies Champion - RE14MCC4 plugs with a .035 gap. Personally, I don't think any spark plug makes a difference except platinum, and the difference platinum make is for the WORSE. I've had good luck with both Champion and NGK over the years.

As far as improvements to the ignition system, don't waste your money. The stock ignition system can reliably fire the cylinders until over 20 PSI of boost. The Hemi Coil on Plug arrangement means that the factory coil is only doing between 1/4 and 1/8 of the amount of work when compared to a coil from a V-8 with only a single coil.

These coils are simply coasting along, even under full throttle at max RPM. I honestly don't think the $400.00 expense of MSD coils would net you a single HP on an otherwise stock motor.

As for bolt-ons, there's a bunch of them. Cold air intake seem to be good for a bit of power, cat back systems help too, but headers seems to help the most. One poster picked up 24 RWHP from a set of aftermarket headers. Cam swaps also unlock a lot of hemi potential.

Best of luck,

Regards,

Joe Dokes
 
Well, we bought it used with just under 61,000 on it. We are the second owners and not sure what the p/o did and didn't do. So, I was just going to do it for the sake of doing it.
The fuel mileage is dropping off a little bit (2-3mpg roughly) and figured doing the plug swap, maybe putting a K&N filter in the factory box might help and bring it back up.
Also, not even sure if the tranny/transfercase/front and rearend lubes have been changed since new??
The thing runs great and makes no noises...this heavy Jeep I would've pitted against the 2004 Mustang GT I previously owned!! Get's up and scoots!
Also, when we first bought it, it got 19mpg cruising at 80mph down the interstate going to Illinois. We plan on heading to IL for thanksgiving....a 1000 mile trip one way....and wanting to get better mileage.
Anyways...thanks for the help everyone!
 
i had a TON of trouble with E3's ion my 2500 ram they showed engine codes and fouled out in less than 10k miles I keep the Stock plug and run a cold air box and bullydog programer
 
Went ahead with the stock Champions. The plugs I pulled out were horrible looking. Factory gap is .045". The electrodes were so worn down that the gap was .060" on most of em. The base of the ceramics also had this orange rusty lookin stuff on em too. I almost wonder if those were the original plugs from the factory....surely if they were changed at 60,000mi like they should've been they wouldn't have worn that much?? There was no anti-sieze on the threads either.
Also, I put a K&N filter in the stock box. Jeep has a little bit more on the low end now.
We'll see what kind of mileage it gets on the interstate in a couple weeks.
Changing the plugs in this thing wasn't as bad as I thought it would be, actually fairly easy to get all the coils out and the plugs as well. Only thing was how long it took.
Anyways, thanks for the suggestions everyone!!!
Oh, about headers. Who makes a set of headers for the Commander?? I've looked on ebay, and have searched in Google but have yet come up with anything. Would like some headers with a set of 40 series flowmasters :)
 
I would run whatever Chrysler says. Gimmick spark plugs are just what the name says. A gimmick to take your money.
 
StrokerScamp said:
I would run whatever Chrysler says. Gimmick spark plugs are just what the name says. A gimmick to take your money.
Click to expand...

Lol, yeah, even the dude at Autozone told me not to run platinums in it but to run the factory copper. Said that the platinums might last a little longer but performance wise...they suck. I was shocked that he knew that much about it....usually it's me explaining stuff to them....no offense to anyone working at Autozone but sometimes they don't hire the brightest stars to work there. That's not saying I know everthing there is to know about these things, obviously, because I asked for you guys' help. But, just sometimes you wonder, really?, how did you get a job here??
There's two chicks that work at the Autozone where I go and I know for a fact they know more about cars/parts/performance than most of the guys, even the manager!! As a matter of fact I usually try to get one of em to help me when I go up there.:notworth:
 
Yeah, the big box parts stores usually don't impress. I have good luck with O'Reilly's around here.
 
Considering the condition, I bet they were original.

Like the quote about gimmick plugs, the gimmick is they take your money.

Regards,

Joe Dokes
 
I see it's an old thread, but I think it is worth updating since 5.7 HEMI will stay with us for another 20 years at least
Regarding materials, platinum or iridium are hands down better than copper. NGK LZFR5CI-11 are the same as OEM NGK LZFR5C-11 but made of iridium, so I would call them the best spark plugs for the 5.7 HEMI.
Also, here is a good article on this topic worth sharing:
Best Spark Plugs for 5.7 HEMI: How to Choose the Proper Ones
 
I put NGK's in mine at about 100,000 miles on my truck 17,000 miles later no issues. If you do the swap yourself you'll save hundreds just be careful with the clips on the coil packs.
 
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