MSD promag 12

Discussion in 'PSI Superchargers Tech Questions' started by overkill69, Sep 9, 2007.

  1. overkill69

    overkill69 Member

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    Has anybody made big power with a 12 amp MSD. We are putting out cylinders. Sometimes egt will drop in the middle of the run and recover at higher rpm. We flowed the fuel system and leaned it out a lot hoping it would help. It picked up mph but is still showing cold plugs on 2 cylinders.Our mag is fresh from Laehy. We are considering upgrading it to a 20amp. We've changed the wires and all that stuff.
    The motor is a 540 KB/Olds with high helix@36psi. We use a 7531 digital 7 box for our timing control. Also been thinking about making a lap with no crank trigger or 7531 hooked up just to see if something weird is going on.
    thanks Mike
     
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  2. mark6052

    mark6052 Member

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    enough mag

    You didnt say what you're runnubg for times. I run my car with a mag 4 at 36lbs boost from a HH 14. You should have enough fire power for the boost. maybe the plug gap, or enough grounds to bond the engine to the chassis. I,ve seen too much anti-sieze cause issues. also the mag maybe good but what about the rest of the ignition system? just my 2cnts
     
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  3. altered boy

    altered boy Outlaw Altered

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    sure you've probably considered this... on a promag deal the first sign of ANYTHING strange happening i would change all the plug wires and the coil wire. seen soooo many guys chase 'crazy' issues, spend retarded money and in the end find out a set of plug wires fixed all the problems.

    also... i REALLY wanted a promag 20 and after i started looking for one i started hearing a lot of guys say to stay away from the 20. it's just a hopped up half-breed promag12 (or that is how it was basically explained to me many times) and to either buy a 12 or a 44. is MSD even offering a 20 anymore?
     
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  4. JRB

    JRB Guest

    check that 7531 box out. We ran it on our car, and it was shooting ducks. Then we put our 8973 BACK onto it, and it cleared up.
     
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  5. DQUES

    DQUES Member

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    Msd still offers the 20 amp upgrade . Been using one for 3 yrs ( bought used ) and zero probs with the internals , have had a bad box ( same as a 12 ) . It has been to leahy twice but no probs found with the internals . Please list all of the probs you have heard of with the 20's , I am curious . I have heard the same stuff for years but yet to see anything to support the rumors . Also know many people who have had no probs with their 44 set ups for years but I also know people who carry at least 2 coils , boxes , and generators because they have . Not bashing the 44's , they are the best mag made but they do also fail from time to time .
     
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  6. M Tigges

    M Tigges TAFC

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    We ran a mag 12 from 1999 to 2004 and ran low 80,s @ 240, I remember we were having trouble with our Mag 4 @ E town 1999 and Jay Payne came over and said i got what you need right here!(mag 12), and dont upgrade it to a 20!
     
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    Last edited: Sep 12, 2007
  7. overkill69

    overkill69 Member

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    Thanks for the replies guys. I think the problem is in the 7531 box. Leahy hooked me up with some ideas to try. Sounds like nobody will admit to having success with the 7531 on a promag.
    Mike
     
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  8. WIZBANG

    WIZBANG Member

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    Kind of on the same area, what do you guys use for plug wires ?

    I was told to use the MSD Super Conductors ?
     
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  9. Flyboy68

    Flyboy68 Member

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    Mike how do you get ahold of Leahy? I need to get my Promag 12 and box checked....?

    Josh
     
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  10. overkill69

    overkill69 Member

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    search Electrimotion
     
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  11. Bob Kraemer

    Bob Kraemer New Member

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    Here is Dave's # (740) 362-0251 & link http://www.electrimotion.com/index.htm
     
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    Last edited: Sep 13, 2007
  12. overkill69

    overkill69 Member

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    wires

    I think most everybody runs MSD wires. Keep a log of the resistance values especially the coil wire.
     
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  13. kmans57

    kmans57 New Member

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    Upgrade to 44 from 12, how much timing to decrease?
    Currently running 28° with pro mag.
    Blown alky bbc 548.
     
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  14. Mike Canter

    Mike Canter Top Dragster
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    Timing will remain the same. Both the 12 and 44 have circuits to keep the timing stable during the rpm range. Only the non MSD mags vary timing depending on load
     
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  15. lawnmowerman

    lawnmowerman New Member

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    dont use the re limit chip. i ran 5.70 in 1994 tad ,but had trouble with plug in rpm chips
     
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  16. J.M.J pegasus

    J.M.J pegasus New Member

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    I ran a pro mag 12 on a 548 solid headed new century bbc ..whipple r980 screw high OD..changed everything we could with it...new boxes..plug coil wires..cap and rotor..a different generators..2 more new box...re-wire it,new msd switches,new grounds .016to.012 plug gaps.still would put out random cylinders above 7000rpm with max rpm it would only go would be 7400 and 38+#s of boost..also had fuel system setup by randy anderson..after about 2 years of headaches this past weekend we tossed out the whole mag 12 setup after 2 passes with random misfires and put on a new mag 44 with all new msd gear...turned 8300 rpm made 48#s of boost at 25* timing with APS base setup then corrected for d/a...btw its a dirt/mud drag deal..so Im kinda believer on the mag12 have a limit on cylinder pressure..it being in the high 30s/low 40#s with 10.6/1comp.when it loses its snuff..that based on 3 different generators and boxes..
     
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  17. Will Hanna

    Will Hanna We put the 'inside' in Top Alcohol
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    I can't find specs on a MSD 12's spark energy, but a MSD 20 mag is listed as 240 mj per spark (at the gap).

    I was told the MSD 12 actually puts out less spark than a 6AL box you would put on a street rod.

    As a frame of reference the black MSD 7720 box that many use with a Power Grid system puts out 200-220 mj per spark. An MSD 8 plus puts out 345.

    The MSD Pro Mag 44 puts out over 800 mj per spark (at the gap). I have been told that a mag is measured a little differently than a distributor, and that if measured as a distributor, would measure somewhere in the mid to upper 400's.

    MSD's new CDI coil near plug ignition box that plug n play's with the power grid is capable of 680 mj.
     
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  18. Mike Canter

    Mike Canter Top Dragster
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    This is data that I have on MSD systems

    In order:
    ProMag 44 – 950 milliJoules
    MSD 10+ - 700 mJ
    MSD 8 - 315-345 mJ
    ProMag 12 - 300 mJ
    Digital 7 - 190 mJ
    7AL3 - 160 mJ
    Digital 6 - 135 mJ
    7AL2 - 105 -115 mJ
    MSD-6 - 105-115 mJ

    This was from MSD. That puts the ProMag 20 that Will quoted as being less less than the ProMag 12
     
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  19. Will Hanna

    Will Hanna We put the 'inside' in Top Alcohol
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    For what its worth, if you go to MSD's website right now, it lists the Pro Mag 44 at 800 mJ.
     
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  20. Mike Canter

    Mike Canter Top Dragster
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    #20
    Last edited: Sep 21, 2019

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