Spark plug gap

Discussion in 'PSI Superchargers Tech Questions' started by Templar Motorsports, Jun 26, 2020.

  1. Templar Motorsports

    Templar Motorsports New Member

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    I'm sure this has been asked before. When running a Mag you want to gap the plugs @ .016 to .018
    so you don't get a crossfire in the cap at high pressures. With the new stuff out like the MSD Pro 600 and there are no moving parts. Should a person run a bigger gap?
     
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  2. Mike Canter

    Mike Canter Top Dragster
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    I think you should run .015” gap in all blown alcohol applications. The main reason we switched from .018” down to .015” was during staging and launch the engine is so rich that the smaller gap had a better chance of firing in that Super wet high pressure environment.
     
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  3. Ron C

    Ron C Jr. Dragster

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    But, seems contrary to Mags potential energy output. Narrower gap requires less energy build up to jump across gap. The way electricity works, seems a larger gap which would increase the energy level would address the problem better. What am I missing?
     
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  4. Mike Canter

    Mike Canter Top Dragster
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    High pressure super wet environment makes it way harder for the spark to jump a wide gap
     
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  5. Ron C

    Ron C Jr. Dragster

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    OK,...I thought you said staging and launch.....?? Trying to understand something here.
     
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  6. Mike Canter

    Mike Canter Top Dragster
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    Staging and right after launch is normally when it is the wettest.
     
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  7. Ron C

    Ron C Jr. Dragster

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    Trying to understand the physics here. I grasp how electricity/Ignitions work pretty good, including in the combustion inviorment. Narrowing the gap seems contrary to improve the situation at Idle/launch combustion pressures. Logic points to the opposite. Of course, a larger gap might not be conducive as cylinder pressure increases. I see an opportunity here for a new market. Variable gapped plugs.
     
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  8. Mike Canter

    Mike Canter Top Dragster
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    Didn’t say anything about idle. It is for staging and right after launch. You can normally see raw fuel coming out of the pipes during those times which means there is a ton of fuel inside the chamber. All that fuel and the high pressures in the chamber make it hard for the spark to jump the gap so you get a misfire.closing up the gap makes it easier for the spark to jump the gap so reduces misfire.
     
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