LT1-LT4 Modifications 1993-97 Gen II Small Block V8

spark plug gap help

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Old Mar 12, 2010 | 03:04 AM
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Default spark plug gap help

What gap for a NGK TR6 plug on a mild stock LT4 build with CC503 cam? It has full bolt ons and a 11.2 comp. Any help would be great
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Old Mar 12, 2010 | 03:51 AM
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.040 .
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Old Mar 12, 2010 | 04:09 AM
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Sounds good, just out of curiosity what happens when you make a tighter gap? Does the motor idle different or get a better combustion?
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Old Mar 12, 2010 | 09:14 AM
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i gaped mine to .50 on a lt1 build with a 503 and bolt ons
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Old Mar 12, 2010 | 11:15 AM
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From what I understand, in a higher compression engine, the risk of "blowing out" the spark is high. A narrower gap provides less spark area for the intake charge to "hold onto," keeping the spark from blowing out.
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Old Mar 12, 2010 | 11:19 AM
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id go with .035 with the higher compression
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Old Mar 12, 2010 | 02:16 PM
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Originally Posted by SexyTransAm
id go with .035 with the higher compression
thats what my 383 11:1 LT1 is at with my tr6 plugs
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Old Mar 12, 2010 | 03:21 PM
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K I'll go with the .035 gap
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Old Mar 12, 2010 | 04:48 PM
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.035 is not needed for N/A but suit yourself. You want the biggest gap you can run for the best burn. Toitight a gap when its not needed is wasteful. Might as well start retarding your timing like Nitrous guys do too. I don't see what the point of building a N/A engine is if you're not going to optimize it.
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Old Mar 12, 2010 | 05:20 PM
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Originally Posted by gregrob
.035 is not needed for N/A but suit yourself. You want the biggest gap you can run for the best burn. Toitight a gap when its not needed is wasteful. Might as well start retarding your timing like Nitrous guys do too. I don't see what the point of building a N/A engine is if you're not going to optimize it.
My former tuner and retired GM engineer suggested I run .035 gap on my NA H/C build with ~11.5 CR. I trust his word as gospel!

Higher compression washes out spark at high rpms, and dropping the gap from .050 to .035 like he suggested helped drivability and noticeably cleaned up the top end.
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Old Mar 12, 2010 | 06:31 PM
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Im not suggesting .050 though, am I...

Its likely that .040 would have worked well in your case too.
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