Blown BBC Ignition upgrade

Discussion in 'PSI Superchargers Tech Questions' started by Sartistic1, Jun 18, 2014.

  1. Sartistic1

    Sartistic1 New Member

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    I run mud and sand drag, blown alc 572 and my current combo is making 22psi and my problem is the car lays flat, change timing, fuel, clutch adjustments but the power hits a wall at 22 psi. The theory I'm working on right now is that my Promag 12 just isnt enough. If I change pulley config to achieve 19 psi, it starts to pull but just not as hard as it should, at 22 the car launches hard and just pretty much stops pulling at 7000 rpm. Just hoping to get input from anyone with experience with this, I don't have anyone close I can borrow a bigger mag from to rule this out and its a bit expensive to be wrong about it. I just had a disappointing weekend when it hit me that I ran into this once before with a msd 6 on a blown alc motor, did 11 psi and that was the barrier.
    This is my first post so I should apologize for not being familiar with posting.
     
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  2. pnconcepts

    pnconcepts Member

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    What do you gap your plugs at? Assuming .018 tighten them up to .014....... or buy a Pro Mag 44 I know a guy who has a used Chevy Generator.
     
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  3. Sartistic1

    Sartistic1 New Member

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    Im at .015, was thinking of trying it a bit tighter. Do my symptoms sound like it could be not enough power at the plug? I know the guys with the 20's and 44's have a much more powerful exhaust note.
     
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    Last edited: Jun 18, 2014
  4. summitcb

    summitcb Member

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    I had the same problem, compression and boost were too much for the MSD 12 mag. I changed up to a MSD20 and the problem went away. I eventually stepped up the motor again and needed a MSD 44. I would recommend upgrading to a MSD 44 and never worry about enough spark again. The MSD 44 does require some extra pcs, separate coil and shut off solenoid that take up a little more space, add a MSD 7730 timing controller and away you go even on less than perfect tracks.

    Steve
     
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  5. Sartistic1

    Sartistic1 New Member

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    Thanks for the feedback. Ive seen some 44 systems used for around 2k.
     
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  6. SoDak

    SoDak Active Member

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    We run BBC's, SM IV's, 30 psi, .016" gap and won this last weekend running 8-9,000 RPM going down the track (tractor pulling).

    I wonder about your fuel system getting rich at this RPM (we had that years ago) and we've also run into similar symptoms when intake valve springs started to get too weak (it was only a couple of them).
     
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  7. Comax Racing

    Comax Racing Member

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    I agree with this ^^^^^^^^. I used to run a SM III with 27psi, it would pull all the way down track at close to 8000rpm. .015 gap No issues with spark.
    Plugs were always lit.

    Corey
     
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  8. Blownbudget

    Blownbudget Member

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    I very much dout you are at the limit of a pro mag 12 at 22psi !!!,have you had the mag and points box checked out ???,I've run a lot more boost than 22psi with super mags and pro mag 12's never had any issues other than when I've been way out with the tune ups fuel system wise !!,if it was me before spending your hard earned money on a replacement ignition system get the one you have checked out first
     
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  9. Bjs344

    Bjs344 Member

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    For what it's worth, my 7al2 keeps them lit through 8500 at 21 psi with .013 plug gap. I've got 6-8 runs on a set of plugs, but know guys that HAVE to change them at 2-3 passes.
     
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  10. Wildcatracing

    Wildcatracing Member

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    BBC ign

    we run a MSD-10+ on a 532, no probs up to 38 psi so far
     
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  11. Sartistic1

    Sartistic1 New Member

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    Thanks for all the imput, talked to msd and i think im going to have my box checked out before the next race. its the 8105 not updated to 8106 so it could be causing my issues, never had it checked before, only the mag.
     
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  12. BUTCH

    BUTCH Member

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    what do your plugs look like after a pass?
     
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  13. summitcb

    summitcb Member

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    I must add that I was running 32 lbs of boost on 427 BBC before I had problems.
    Actually I didn't even know I was dropping cylinders on the top end until someone at Racepak looked at one of my runs and told me. They had me tighten from .018 to .016 and look at the Racepak again and it was better but not perfect. I switched up to the MSD 20 and the rpm line was smooth. I have since built a 540 with a Fowler K11 and that set up required a 44. So I have paid for three different mags and I wish I would have listen to the experience of others in the beginning and bought the MSD44 first. It would have been overkill for the first motor, good for the 2nd motor and required for this last motor.

    Steve
     
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  14. cheyenne

    cheyenne Member

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    ??????

    How much timing are you running with the Pro Mag 12?
     
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  15. buzillamini

    buzillamini Member

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    If you think you may be having ignition issues call Spud at FIE. he will get you set straight. a 44 mag is overkill unless you are running nitro.
     
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  16. jody stroud

    jody stroud ZOMBIE Top Dragster

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    Every good running TAD and TAFC run 44 amp mags and none run on nitro ( except the injected A Fuel cars ) . Quit spending good money trying to buy something that is supposed to be "just as good " as a mag 44 and get the real deal. Bob Wyman was working on a 46 amp mag until the nhra found out about it and told him it would not be legal. Voltage may be the same but it's the amps that make it so effective at lighting a charge. Hell you could weld with 44 amps and a 3/32 welding rod.
     
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  17. Blownalky

    Blownalky Top Sportsman

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    Not to mention all the blown alcohol Pro Mods. Oh yeah, the turbo guys too.
     
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  18. summitcb

    summitcb Member

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    Cheyenne

    Not sure if your question was for me but I run 32 degrees, depending on track I will take some out a launch and 5 out at the shift.

    Steve
     
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