# which spark plugs should I use?



## purposebuiltsleeper (Feb 28, 2013)

I'm not sure which spark plugs to use in my current application to get the best performance. I'm currently running an aem cold air intake with a stock tb and stock intake manifold, slp diablosport tuner, comp cams xfi rpm camshaft, lifters, pushrods, valve springs, kooks 1 3/4" longtubes, catless mids, and slp loudmouth.

I bought bosch finewire but I don't want to put them in if there's something out there that's better for around the same price. I think i paid 7 or 8 bucks each for them. Spark plugs are kind of my weakness and I haven't really spent a lot of time looking into which ones would be the best ones to use with my set up.


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## rickm (Feb 8, 2012)

man, im gettin old...


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## silversport (Mar 23, 2007)

if you have an '04-'06 GTO, I would recommend the stock Iridiums...honestly I've never seen any boost from plugs other than they seem to work better because they're new...

Bill


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## svede1212 (Nov 1, 2005)

Get copper NGK TR55s and gap to around .050. They are cheap and work extremely well. Replace them every 25k or so


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## 68OldGoat (Nov 23, 2009)

> Get copper NGK TR55s and gap to around .050. They are cheap and work extremely well. Replace them every 25k or so


I have used copper plugs in one of my prior cars and Svede is right they work great but don't last very long (tips deteriorate rather quickly). The stock Iridium's will last at least 3 times longer than the copper so the cost of replacing the coppers 3 times to 1 change for Iridium's is the question.


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## silversport (Mar 23, 2007)

svede makes a good point of course...I was thinking of ease of use..set it and forget it...but I know a LOT of the Corvette guys using the same engines have used those NGK TR55s with great success...

Bill


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## svede1212 (Nov 1, 2005)

The metal of the plug is used to conduct electricity. Copper is only second to silver in conductivity and why it is superior. The trade off is longevity but it is a cheap and easy maintenance item.

To wit:
Copper Spark Plugs vs. Iridium and Platinum: Understand for Top Performance - CarsDirect

On the conductivity chart Iridium's conductivity would be less than mercury

Electrical resistivity and conductivity - Wikipedia, the free encyclopedia


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