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What Spark Plug Gap?

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Old Sep 10, 2002 | 01:01 PM
  #1  
JR-CRUZN-C5's Avatar
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Default What Spark Plug Gap?

There seems to be some controversy over what gap to use on the C5 after market plugs being used i.e. NGK, Champion, etc. is it .35 - .45 - .55 - .60.
The tech at NGK told me .55 the chevy engine builders feel .35 - .45.
So what do you guys think!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!! !!!!!!

JR
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Old Sep 10, 2002 | 03:14 PM
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Default Re: What Spark Plug Gap? (JR-CRUZN-C5)

I put mine between .55 and .60 :)
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Old Sep 10, 2002 | 03:16 PM
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Default Re: What Spark Plug Gap? (CMilVette)

depends if you have a power adder... Stock gap is .060. I gap mine around .045 with N2O
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Old Sep 10, 2002 | 07:22 PM
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Default Re: What Spark Plug Gap? (JR-CRUZN-C5)

I'm running stock. NGK's came @ 57, running great.
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Old Sep 10, 2002 | 07:23 PM
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Default Re: What Spark Plug Gap? (TexasRedY2K)

.060 for stock gap plugs, for every 50 HP OVER stock HP level, whether it's nitrous, N/A or FI power, decrease the gap by 0.004 per 50 HP OVER stock.
So 150 Nitrous shot on a STOCK (showroom stock) car would be a decrease of 0.012 = 0.048 gap. If you added 50 HP in N/A mods and 100 in Nitrous, 0.004 x 3 (3 multiples of 50 HP) = 0.012 decrease in gap = 0.048 gap size.
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Old Sep 10, 2002 | 07:46 PM
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Default Re: What Spark Plug Gap? (JR-CRUZN-C5)

I'm running .057, no problem. :)
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Old Sep 10, 2002 | 08:49 PM
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Default Re: What Spark Plug Gap? (carpe dm)

I run the stock NGK TR 55's gap of .057, but after reading about plugs on http://ls1.com/index_faq.html#601 will probably try the .050 gap they recommend. Check out the article pretty informative! :yesnod:
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Old Sep 11, 2002 | 10:31 AM
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Default Re: What Spark Plug Gap? (JR-CRUZN-C5)

Here is a bit more fuel for the fire!!

NGK says .55, Vinci Hi-Performance says .50, Finish Line Performance says .45, Opel engine builders say .35 and on and on and on!!!!!!!!!

Plugs to consider: NGK TR6 @ .55, Champion RS12YC @ .50

JR :blueangel:


[Modified by JR-CRUZN-C5, 2:33 PM 9/11/2002]
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Old Sep 11, 2002 | 10:41 AM
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Default Re: What Spark Plug Gap? (JR-CRUZN-C5)

Running NGK TR55's at a .057 gap in my coupe.
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Old Sep 11, 2002 | 10:35 PM
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Default Re: What Spark Plug Gap? (JR-CRUZN-C5)

JR-CRUZN-C5, it has been stated that NGK does not recommend changing the stock gap of their plugs by more than plus or minus .010, they recommend you change which plug you use instead. Read posted article above in my prior post at ls1.com.
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Old Sep 12, 2002 | 01:23 AM
  #11  
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Default Re: What Spark Plug Gap? (Xssesive)

I called NGK talked to a tech, described my mods. he recomended TR6 gapped at .55. What do make of that?????????????????????????????

JR :U
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Old Sep 12, 2002 | 10:57 PM
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Default Re: What Spark Plug Gap? (JR-CRUZN-C5)

Just telling you what I read, bro. Why does he want you to run a colder plug? I plan on changing plugs next year back to same NGK plugs but gapped a little tighter at .050 . One of the other guys said he was getting timing retard until he closed the gap and then it went away.
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Old Sep 13, 2002 | 10:31 AM
  #13  
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Default Re: What Spark Plug Gap? (Xssesive)

My C5 is over at FLP getting Vinci Heads & Cam installed I tend to like what they say about the plug gap issue (.045) although Roger Vinci is running a 9 sec. 06 using .050 with N02. They are going to dyno my car with amoung other things a .055 gap and TR6 plugs. (I am currently running the Champions gapped at .050 with no problems!

JR
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Old Sep 13, 2002 | 02:48 PM
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Default Re: What Spark Plug Gap? (Xssesive)

Just telling you what I read, bro. Why does he want you to run a colder plug? I plan on changing plugs next year back to same NGK plugs but gapped a little tighter at .050 . One of the other guys said he was getting timing retard until he closed the gap and then it went away.
i had the same problem on my '01 and after calling ngk i found the 50 hp rule.
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Old Sep 13, 2002 | 05:07 PM
  #15  
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Default Re: What Spark Plug Gap? (C5Noir)

What is the theory behind slimming the gap .004 per 50 hp? What is the gain? Knock control? Burn?

I want to do this now that I have the S/C, but pulling the plugs to do it, ugh.

F
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