Need to replace plugs - cooper,Iridium, or Plat?

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I'm replacing (long overdue) plugs in my daughter's 2011 Kia Soul 1.6L, I believe the OEM plugs are copper, Champions I believe but I haven't pulled them yet to be sure. Anyway, assuming the OEM spec is indeed copper, should I stick to them or is there a performance or mpg benefit to going to Iridium or platinum plugs? I'm inclined to stick with OEM spec unless there's a reason not to. I'm not real worried about the life span, I can live with the 30k interval of copper plugs if need be, I'm more concerned about function and having all the parts play nicely together.
 
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I used iridiums in my copper application and didn't notice any real differences. They did last longer, but considering I do them myself, it's not super critical. Also, they are 5 times the cost, and they did not last 5 times the interval.
 
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First, figure out what the OEM plug really is. You've posted, but are not sure of what you're working with. That's a bit of a waste of time and effort. Unless there is a solid, valid reason to do otherwise... replacing with the same plug is an excellent idea.
 

OVERKILL

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Originally Posted By: Olas
Copper is a better conductor than other plug metals, and places marginally less strain on coils. Only downside is life..
True, but even "copper" plugs don't have copper firing surfaces, they are steel. The steel tipped plugs erode faster than the precious metal tipped plugs but are, as you mentioned, easier on the coil(s). Whether that's of consequence or not entirely depends on the application and of course a good rule of thumb is to always go by what the manufacturer specs.
 
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Most Plugs are ALL copper core, so that shouldn't enter in the equation. Inconel/Monel (a tough SS alloy) is the STD plug. the link mt silv04 shows a dual GND electro side firing plug. Im going to look at the NGK site ... though I bet they use Champions or denso. OP, How do you know you are over due? What is the interval in the manual? 30, 60, 100k?
 
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Im seeing CHamp RER8MC. That a cold plug for a smogger. Good show KIA! Most Asian engines run too hot a plug and the car runs poor or kills and glazes the plug when pushed. SCHOOLING: Most Plugs are ALL copper core, so that shouldn't enter in the equation. This materal selection has NOTHING to do with conductivity of electrons only HEAT transfer ( like Cu bottom cooking pans. This is a HIGH TENSION system and does not require low impedance wires or conductors - this is a fundamental misunderstanding of high voltage theory by most laypersons. Inconel/Monel, a tough SS alloy, is the STD plug metal (on a good std North AMERICAN designed plug - not NGK std junk smile
 
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MoreCowbellAz

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Originally Posted By: ARCOgraphite
OP, How do you know you are over due? What is the interval in the manual? 30, 60, 100k?
The manual states a 30k interval, and since it's my daughter's car there's a good chance they're the original plugs which means there's like 88k on them. At minimum they have 40k. I'll be curious to see what they look like when they come out. I've read online they'll probably be Champion brand, and I can get those at Napa for $2 so that's probably what I'll do. All the parts store want to sell me the Iridiums which is why I asked my original question, I didn't see a need but maybe there's something I need to know. I'd like to have the new plugs in hand when I pull the old, so I'm thinking ahead.
 
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If they are an easy changout run the std Champs; If you have to remove the upper intake manifold and runners use IR of the correct heat range. #8 is cold for a Asian plug - almost in the turbo.SC range smile
 
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MoreCowbellAz

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Incidentally, as I'm sure a lot of you folks can relate to, maintaining your kid's car is a challenge when you don't see it very often (my daughter was in college out of town). So I've been methodically going through all the maintenance items now she's local again; oil/filter changes, air filter, cabin filter, ATF, plugs, PCV, etc. She's a good sport too, she comes out to help so she at least knows a little more about her car. Oddly, it's good dad/daughter time.
 
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Originally Posted By: OVERKILL
Originally Posted By: Olas
Copper is a better conductor than other plug metals, and places marginally less strain on coils. Only downside is life..
True, but even "copper" plugs don't have copper firing surfaces, they are steel. The steel tipped plugs erode faster than the precious metal tipped plugs but are, as you mentioned, easier on the coil(s). Whether that's of consequence or not entirely depends on the application and of course a good rule of thumb is to always go by what the manufacturer specs.
If the plugs are hard to get to, it's worth getting a longer lasting version. I don't like the shrouding of the spark multiple ground electrode plugs cause.
 

MoreCowbellAz

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The plugs look pretty easy to get to on this engine. I'll probably do the PCV too while I'm in the vicinity, hopefully that's not a pain. It's surprising how little info there is out on the net for some of the normal maintenance items. Maybe it's because the young hamster people don't worry about such frivolities.
 
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A 1.6L 4 cylinder front wheel drive should be easy to change. If it is standard steel (copper) plug then you can use anything equal or above. Conductivity of the arc should be the same regardless of the electrode material, and plug should have resister matching the factory spec so debating "which material" is more conductive means nothing. The only thing that makes the biggest difference is the tip sharpness, which is related to the material. Precious tip may have finer tip that's easier to spark for the same gap because they are more durable. This is the biggest difference between fine wire racing iridium that last only 30k and the long life iridium that last 120k.
 
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Originally Posted By: MoreCowbellAz
The plugs look pretty easy to get to on this engine. I'll probably do the PCV too while I'm in the vicinity, hopefully that's not a pain. It's surprising how little info there is out on the net for some of the normal maintenance items. Maybe it's because the young hamster people don't worry about such frivolities.
you need to post in the appropriate place. e.g try posting here. http://www.kiasoulforums.com/29-how-diy/ otherwise, perhaps indeed the intersection of young hamster people and shadetree mechanics is low. I would also say to be careful to consider your source. I've had it before that some guy's DIY skipped a step or did something not quite right. I'd pay to get the right info if kia offers cheap service manual access, or even 3rd party like alldata instead of relying on hamster people.
 

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Originally Posted By: PandaBear
A 1.6L 4 cylinder front wheel drive should be easy to change. If it is standard steel (copper) plug then you can use anything equal or above. Conductivity of the arc should be the same regardless of the electrode material, and plug should have resister matching the factory spec so debating "which material" is more conductive means nothing. The only thing that makes the biggest difference is the tip sharpness, which is related to the material. Precious tip may have finer tip that's easier to spark for the same gap because they are more durable. This is the biggest difference between fine wire racing iridium that last only 30k and the long life iridium that last 120k.
But it doesn't jump from the tip, it jumps from the sharpest (and closest) edge. This is why the edge wears off the steel tipped plugs, not the centre. The resistance (usually carbon) in a resistor plug is there to suppress EMI IIRC and has very little to do with the energy required to jump the gap which of course corresponds with gap width. I believe one of the other advantages of the finer tipped precious metal plugs is that the tips are better (due to their size) at "self cleaning".
 
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Originally Posted By: ARCOgraphite
Im seeing CHamp RER8MC. That a cold plug for a smogger. Good show KIA! Most Asian engines run too hot a plug and the car runs poor or kills and glazes the plug when pushed. SCHOOLING: Most Plugs are ALL copper core, so that shouldn't enter in the equation. This materal selection has NOTHING to do with conductivity of electrons only HEAT transfer ( like Cu bottom cooking pans. This is a HIGH TENSION system and does not require low impedance wires or conductors - this is a fundamental misunderstanding of high voltage theory by most laypersons. Inconel/Monel, a tough SS alloy, is the STD plug metal (on a good std North AMERICAN designed plug - not NGK std junk smile
Yeah, sure, NGK is "junk" - you're not very persuasive. The best plugs I have ever used in my German bike are NGK, and NOT than the nineteen electrode Bosch stuff.
 
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