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spark plug gap question

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Old 12-29-2007, 09:13 PM
  #1  
Ecstasy
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Default spark plug gap question

for those who have motors with no power adders, what do you gap your spark plugs at, im curious to see what the different answers are because they recommend 0.054 for our cars and to me that just doesnt seem right, im debating on going with 0.043. but i wanted to get some info first. so what do you gap your spark plugs at?
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Old 12-29-2007, 09:25 PM
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POISND U
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Default RE: spark plug gap question

.052 to .056

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Old 12-29-2007, 09:29 PM
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Default RE: spark plug gap question

Why doesn't the factory recommended 0.054" sound right? [/align][/align]With the COP system there's a ton of voltage available (40kV+), far more than enough to ionise a 0.054" gap at any chamber pressure you'd ever see in an n/a engine...[/align]
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Old 12-29-2007, 09:41 PM
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Default RE: spark plug gap question

well i know, im just saying, im going to stick with 0.054 but i was debating on doing 0.043. i just put accel coil packs on which are 42,000volts.
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Old 12-29-2007, 09:56 PM
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Default RE: spark plug gap question

I say gap them at 43 like u said my dad and his friend were getting on me cause I gapped them at 54, I will be re-gapping them to 44 one of these when its warmer out
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Old 12-29-2007, 10:01 PM
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Default RE: spark plug gap question

well the only reason i asked is because my friends 99 gt, he gaps his plugs at like 0.034.
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Old 12-29-2007, 10:12 PM
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Default RE: spark plug gap question

It takes a maximum of about 25 kV to ionisea 0.050"gap on a properly operating sparkplug, at the highest chamber pressure you'll ever see in an n/a engine. [/align][/align]I have never measured the actual voltage on my Mustang as I do not have a calibrated inductive pickup for the COPs. However on my old supercharged (12 psi) '90 Miata running a 0.036" gap the highest ionisation voltage I ever recorded was about 24 kV; and that was at WOT, full boost,at 5k rpm or so. Usually it was well under 20kV.[/align][/align]Ignition voltage is hardly ever an issue with DIS and COP ignition systems until you get into crazy boost and compression ratio ranges.[/align]
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Old 12-29-2007, 10:16 PM
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Default RE: spark plug gap question

yea i mean i know all of that i was just curious as to who uses what gap. like i said my friend had a 99 gt ran 12.90 in the 1/4, had stock heads, cam & lower intake. he gapped his at 0.034 and it ran great, when hed gap his at 0.050ish it wouldnt run as good, thats why i asked.
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