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Discussion Starter #1
how do you know what the gap is when installing spark plugs? i know generally you're told how much but is there an equation or formula to figure out what the gap should be depending on what mods you have?
 

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A lot of people here will recommend a .060 gap for NA. .030-something for FI.
I have motorcraft coppers gapped to .060. I feel a little bit of difference on the top end.

What plugs are you using???
 

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Discussion Starter #3
denso's. i have a procharger and they're set at .038 now. i want to make sure that's where they are suppose to be or close enough. i've gotten a couple of different responses though that's why i'm asking.
 

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The Librarian
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Moved to ”Forced Induction Chat”...
More often than not, the recommended plugs for forced induction are the Motorcraft Copper Plugs (AZFS22C or SP-463).
Gap is somewhere between .035-.040 IIRC.
Denso plugs have been known to melt and cause some pretty bad damage...
Use at your own risk...
 

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The rule of thumb is keep opening the gap until you get misfiring then just close it back down a bit.

Generally the lower your boost the bigger the gap. at 19psi I'm running around a .035 to .040 gap.
 
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