MSD PRO MAG REV LIMITER ????

Discussion in 'PSI Superchargers Tech Questions' started by FAT HEAD JOE, Dec 6, 2004.

  1. FAT HEAD JOE

    FAT HEAD JOE racer

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    I NEED TO BUY A MSD POINTS BOX REV LIMITER IS THIS THE PART # I SHOULD ORDER 8147 OR IS THERE A BETTER ONE TO GET ? THANKS JOE
     
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  2. Mike Canter

    Mike Canter Top Dragster
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    That is correct. According to MSD the rev limiter version is the 8147 and that is the latest out there right now.
     
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  3. Will Hanna

    Will Hanna We put the 'inside' in Top Alcohol
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    also keep in mind when putting a chip in, it will actually start hitting about 400-600 rpm before the number on the chip.
     
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  4. Norm Drazy

    Norm Drazy Jr. Dragster

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    Also keep in mind that the MSD 44 with a rev limiter can be a real parts killer if the mag drive isn't torsionally stiff. The armature in the generator has a high moment of inertia (flywheel effect), and wants to keep rotating at whatever speed it was going. When it hits the speed setpoint, it very rapidly switches the ignition off and on as the engine RPM rapidly fluctuates from above the setpoint to below it. During the decelerations, the armature gets ahead by an amount determined by the torsional stiffness of whatever connects it to the camshaft gear. Since there is now more lead than intended, the stage is set for beating things up when it starts firing again.

    Norm Drazy
     
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