timing signal

Discussion in 'PSI Superchargers Tech Questions' started by cheyenne, Aug 2, 2016.

  1. cheyenne

    cheyenne Member

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    Is it better to run a crank trigger or just on the Pro Mag? this is a BBC on alky with a PSI c blower and a Pro Mag 12 amp and #8106 box & coil. Any help would be good.

    The reason I ask this ? is I did a rebuilt on the motor and went to an KB block and know the crank trigger won't fire up the motor. But the mag does. It is an MSD crank trigger with flying weights. I'm using a 16v battery.


    Thank you
    Jim
     
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  2. jody stroud

    jody stroud ZOMBIE Top Dragster

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    Not spinning fast enough for the trigger to pickup signal. Switch to 24 volt or live with having to crank on mag and then switch to crank trigger to make the pass. It's a common thing to happen.....
     
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  3. Mike Canter

    Mike Canter Top Dragster
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    Make sure the crank trigger air gap is around .045 to .050. Best to use a zip tie as a feeler gauge. Figure this on a 2500 hp motor one degree of timing change is around 75 to 100 hp so the problem with a mag drive is timing jumping around maybe more than one degree whereas a crank trigger will be right on
     
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  4. cheyenne

    cheyenne Member

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    Mike
    So I guess the answer is buy a #7990 from msd so I can start on the mag then switch to the crank trigger.
     
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  5. Mike Canter

    Mike Canter Top Dragster
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    That is correct. Both MSD and Electrimotion sell them.
     
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  6. cheyenne

    cheyenne Member

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    Thank you Mike I will order one. It just puzzles me why now it won't start on the crank trigger it did for two years before the block change.
     
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  7. Mike Canter

    Mike Canter Top Dragster
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    Either your stripes in the blower are new, or your starter is different or starting to fail or the battery is getting weaker. Make sure that crank trigger air gap is down around .045".
     
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  8. mogenss

    mogenss Member

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    Have you guys tried to use a relay or solid state relay wired to the onboard starter button so when you are on the starter button the timing is coming from the MAG and when you release the starter button it switches to the cranks trigger (could also be delayed).

    Just thinking KISS when things are heating up in the staging lanes :)
     
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  9. cheyenne

    cheyenne Member

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    Ok I bought a #7990 and the leads are to short can I add on to them with no problems?
     
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  10. overkill69

    overkill69 Member

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    Try not to extend leads or add connections in the trigger circuit. It's very sensitive to rf noise.If you do ,get up to speed on shielding.
     
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