msd 7 digital plus functions?
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msd 7 digital plus functions?

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    senior member turbo wog's Avatar
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    Default msd 7 digital plus functions?

    not sure what the left dail is for or the next 2 to the right of it .....or the next two after that also. i just used the basic max rpm . ....my thoughts are that the step 2 is actualy step one for launch ,like 5500 max rpm then it opens up after few seconds after launch then the max is set higher for wot ?
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    senior member turbo wog's Avatar
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    o.k. i read the instructions & have a different question! if the step retard was to be used with a vacuum/ boost switch of sorts that activated at say 5psi of boost (adjustable) what should the max timing be set at? would it be more responsive if i maxed the retard out & bumped the timing say to 40* ,then when at boost or into mild boost the timing drops to 30*? do people already do this with the these or fancier programable ones & how do they do it with this one? i did read about the nitrous activation but i am interested just in the boost appllication, thanks- turbo wog
    Last edited by turbo wog; 07-06-2012 at 09:27 PM.

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    senior member turbo wog's Avatar
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    ttt!!any ignition gurus out there ?

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    Senior Member Hass828's Avatar
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    Quote Originally Posted by turbo wog View Post
    not sure what the left dail is for or the next 2 to the right of it .....or the next two after that also. i just used the basic max rpm . ....my thoughts are that the step 2 is actualy step one for launch ,like 5500 max rpm then it opens up after few seconds after launch then the max is set higher for wot ?
    Just a guess here because I dont have the instructs you do. I would say that dial first needs to be set to #2 for 8cyl.
    The second & third dials are for how much retard you want pulled per lb of boost. If you want 1.5 degrees pulled per lb of boost then you would set the sec dial at 1 and third dial at .5 - you add them together.
    The two step will have a wire that activates it for a transbrake or however you would want it to activate and once again the are added together to get the desired rpms,
    Then you have the last two dials that are added together to arrive at your max rpm limiter.
    Last edited by Hass828; 07-19-2012 at 06:39 AM.
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    Senior Member cyclone's Avatar
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    Set your max timing at the distubutor and use the step retards in the digital 7 to pull timing out when the engine sees boost. The step retards are activated by sending 12v to a wire (pink for step 1) and are active whenever the wire has power. Put power to more than 1 wire and the amount is retard is cumulative.

    You can ramp in and out the retard using the digital 7 to soften the retard activation.


    If this is confusing pm me and I'll explain it over the phone.
    Mike

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    Senior Member ap67et10's Avatar
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    I've never used the 7 box, maybe its a great box, I have no clue. What I do know, is that the idea of setting a mechanical timing to meltdown mode (with boost) then having a single 12v wire to a single (dumb) box as the method of pulling timing back to where you will no longer melt the engine down....well....that seems....risky. Now i'm sure many are thinking "well how is this different than full efi where electronics control everything" yes thats right...with a full blown efi they control everything, which means they have failsafes built in for over boost, overly lean...whatever. its a smart box that controls ALL the other components of the system and creating warnings and safties is very easy because of that total control. If this box gives up the ghost, or you get a corroded connection, or loose connection, or even a bad switch...you can do all this engine building work over yet again. If this were a pure drag boat, I'd have less hesitation, but on a lake boat where its used so much more, and checked much less....I just wouldn't do it.

    I'm sure there will be plenty of people that say how they have never had any problems with this box...great! still wouldn't do it. the consequences far outweigh the benefits in my opinion.


    Andrew
    Last edited by ap67et10; 07-19-2012 at 11:26 AM.

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    senior member turbo wog's Avatar
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    thanks haas, for some reason i totaly missed the step retard function. .cyclone, ramp in & out of boost? soften? .... andrew point taken , i think i would set timing @ 37* & pull 7* out at full boost, (rough estimate) using step retard . i have ran it at 40* & it didn't like it at all.not on purpose, it crept up on me!
    Last edited by turbo wog; 07-19-2012 at 11:29 PM.

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    Senior Member Red Rocket's Avatar
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    Why do you think you need to run a boost retard? Why wouldn't you just set the timing for full boost and run it that way. In a jet boat can't see the need for changing the timing.

  11. #9
    senior member turbo wog's Avatar
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    Quote Originally Posted by Red Rocket View Post
    Why do you think you need to run a boost retard? Why wouldn't you just set the timing for full boost and run it that way. In a jet boat can't see the need for changing the timing.
    to see if i can get a snappier throttle response ,more acceleration & better fuel consumption at cruise.

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