pro mag dropping rpm

Discussion in 'PSI Superchargers Tech Questions' started by ProMod83, May 9, 2014.

  1. ProMod83

    ProMod83 Member

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    Hey guys had some issues dropping engine rpm. We changed coil, points box, grid, crank trigger, efi box, battery, plugs no luck. We think maybe its the mag or a phase problem. The car burns out clean at 7500rpm stages and leaves clean then about 2seconds into the run drops rpm. We tried running the mag off its own trigger and its way worse acted like it was on a rev limiter from the second I let go of the tb. Has anyone seen anything like this before.

    Weird thing is it seemed less of an issue with a big launch retard and got worse the more timing we added.
     
    #1
    ProMod83, May 9, 2014
  2. Mike Canter

    Mike Canter Top Dragster
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    You never said anything about changing plug wires of coil wire. First thing is to replace the coil wire. Seeing what you have already changed you can eliminate everything but the wires.
     
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    Mike Canter, May 9, 2014
  3. ProMod83

    ProMod83 Member

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    Mike, first thanks for I the reply. I didn't mention the coil wire or plug wires because we didn't have those with us to change. Short of the mag and wires we changed everything else. I did think maybe the coil wire being it sees more than the plug wires but I figured it would be more random but maybe once cylinder pressure gets up it labors.

    It was dropping laying car over then actually accelerating through the spot but it has now gotten worse where it lays over so hard the run is done.
     
    #3
    ProMod83, May 9, 2014
  4. ProMod83

    ProMod83 Member

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    I just removed the mag from the mag drive and the coupler on the bottom of the mag as a slight bit of play it feels like in the key way. I tried to remove the aluminum coupler but it will not release the shaft maybe it jumped and squashed the key way.
     
    #4
    ProMod83, May 9, 2014
  5. Mike Canter

    Mike Canter Top Dragster
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    I have had that coupler wear and all it does is change the timing some when you come up on rpm if running on the mag. Does not come into play if on the crank trigger. If it has slack then you should still replace it
     
    #5
    Mike Canter, May 9, 2014
  6. SullivanPulling

    SullivanPulling Member

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    Brass gear

    Check the brass gear on the mag base shaft. It may be worn or the shaft may be bent. We have had the same thing happen and the brass gear was worn from a bent shaft. Just something to check pretty easy to see if that's your problem.
     
    #6
    SullivanPulling, May 10, 2014
  7. kosky racing

    kosky racing Comp Eliminator

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    quick fix

    Send to electramotion if there a problem they will find it send them everything box and coil
     
    #7
    Last edited: May 10, 2014
    kosky racing, May 10, 2014

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