Why So Many Plugs?

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Jul 31, 2012 | 11:52 AM
  #1  
Now that I'm in the right forum, can anybody tell me why there are so many plugs in the 3rd gen. 4.7l, and if using all platinum plugs instead of half-n-half would make a difference in performance and economy?
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Jul 31, 2012 | 12:01 PM
  #2  
Less wasted fuel..one ignites before at TDC and one ignite just after TDC
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Jul 31, 2012 | 12:23 PM
  #3  
Quote: Now that I'm in the right forum, can anybody tell me why there are so many plugs in the 3rd gen. 4.7l, and if using all platinum plugs instead of half-n-half would make a difference in performance and economy?
Welcome to the forum. I'm not sure about mixing and matching. Mine only has 8 plugs. I do know that my truck hated platinum plugs. I would stick with whatever the manual recommends. Someone with dual plugs will chime in I'm sure.
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Aug 2, 2012 | 08:23 AM
  #4  
Whats this with dual plugs...is that an 08+ thing? Never heard of that before...
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Aug 2, 2012 | 10:00 AM
  #5  
More power,less emissions. It is very common especially on German cars like a Mercedes Benz V6 and other Chrysler motors like the Hemi
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Aug 2, 2012 | 01:15 PM
  #6  
2008+ have them. Also called a waste spark as it does a 2nd burn to help clean up the emissions.

As to the what brand to buy? I would also suggest staying with whatever the manual recommends. I think one set has a lot longer service life than the other but not sure the exact details, should say in the owners manual.
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Aug 2, 2012 | 06:17 PM
  #7  
2008+ V8s have dual plugs, correct. The V6s never had them.

The lower ones are platinums simply because Chrysler considers them harder to get to. Therefore they made them last longer without changing. For replacement of these or the uppers, I'd recommend either copper or iridium. Platinums don't conduct as well, and if you do more than the lowers in platinum, you may regret it in reduced performance and MPGs.

For brands, NGK, Denso, or Champion are what I've seen recommended around various forums. I purchased Champion iridiums for my upcoming spark plug change myself, because they were rated highly by HEMI owners and were cheaper than NGKs. Some have decent luck with Autolites. Stay away from Bosch, those are designed for smaller European engines.
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Aug 3, 2012 | 06:27 AM
  #8  
And I imagine that it is either too expensive to convert our engines to that, the gains wouldn't be worth it, or it's just not doable ???
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Aug 4, 2012 | 08:19 PM
  #9  
All of the above. You would need a 2nd ign system and the wiring/computer to support it.

The gains are mostly for emmissons.
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