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  1. #21
    Join Date
    Jan 2014
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    Portsmouth NH
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    Quote Originally Posted by BonzoHansen View Post
    What if he wired in a 3rd one like gm did on the 4th gens? Then low kicks both fans on at 6v and high both get 12? Would that lower that initial hit?

    Or scrap it and get a DCC controller. Attachment 168027
    That is a great way of wiring your fans! Thanks for posting that!
    1969 Camaro

  2. #22
    Join Date
    Nov 2011
    Location
    Wylie, Texas
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    168
    Country Flag: United States
    Quote Originally Posted by Richard454 View Post
    Here's an old trick for your alternator.


    Put a diode in series at the alternator on the excite/trigger wire. What the diode does is drops the voltage by about .6v. The alternator is tricked into working harder to compensate for the ~1/2V difference it is seeing. Might help you a lot with the voltages your are seeing.

    We use to do it all the time back in the car stereo days....

    Richard
    That trick would work on the remote sense wire of the alternator but I don't think it will work on the excite/trigger wire. Regardless it's not going to work on a one wire alternator that self excites and has no remote sense.

    One way to help determine why the DD gauge does not match the real voltage is to put your meter probe on the ground terminal of DD controller and put the other lead on a known good body ground (preferably away from the controller). If you're seeing anything other than 0V then you now know that there is a grounding issue somewhere in the harness. It's best to do this test while under heavy load conditions when the gauge is misreading.

  3. #23
    Join Date
    Sep 2016
    Location
    Bakersfield, CA
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    247
    Country Flag: United States
    Quote Originally Posted by blitzer454 View Post
    That trick would work on the remote sense wire of the alternator but I don't think it will work on the excite/trigger wire. Regardless it's not going to work on a one wire alternator that self excites and has no remote sense.

    One way to help determine why the DD gauge does not match the real voltage is to put your meter probe on the ground terminal of DD controller and put the other lead on a known good body ground (preferably away from the controller). If you're seeing anything other than 0V then you now know that there is a grounding issue somewhere in the harness. It's best to do this test while under heavy load conditions when the gauge is misreading.
    Thanks! I've never heard of doing that, will do.
    http://www.TheFOAT.com/92GTA
    1969 Pontiac Firebird
    w/BP 461ci stroker kit, 670 heads & XE274H cam. Primer black w/black interior.
    1992 Pontiac Trans Am GTA w/SLP Performance Package. Dark Jade Grey Metallic, grey leather, T-Tops.

  4. #24
    Join Date
    Feb 2009
    Location
    muggy midwest
    Posts
    534
    Country Flag: United States
    I think there are (2) problems. First is them spal fans have to spin 30,000 RPM to achieve their “advertised” CFM-blade/motor design is weak compared to OEM fans, so there’s one reason why the inferior motor design has to pull crazy amperage to compensate-but hey, Spal does a good job with advertising so they must be great fans.

    Second is imo whoever wired your DD volt gauge should have put the sensing wire ahead of all power drawing components-not just tap into a fuse panel IGN bussbar or whatever. You really need to have 1 central junction from which all of your devices pull power from and land that sense wire there too. This way, the gauge will read as fast as the alternators’ regulator reacts to changes in voltage fluctuations. As for soft start fan control harnesses using relays, they exist because I build them but a good DC Controls unit should be able to handle those Spal fans...even your DD controller should too...oftentimes the reliability of a fan controller is directly related to how well thought the installer made the process.
    "...if at first you don't succeed, try again.
    If you still don't succeed, then quit-no sense being a damn fool about it..."
    -W.C. Fields

    HARNESSWORX
    (formerly gmachinz)

  5. #25
    Join Date
    Nov 2006
    Location
    Mountain Springs, Texas
    Posts
    3,069
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    Quote Originally Posted by H2Ogbodies View Post
    I think there are (2) problems. First is them spal fans have to spin 30,000 RPM to achieve their “advertised” CFM-blade/motor design is weak compared to OEM fans, so there’s one reason why the inferior motor design has to pull crazy amperage to compensate-but hey, Spal does a good job with advertising so they must be great fans.

    Second is imo whoever wired your DD volt gauge should have put the sensing wire ahead of all power drawing components-not just tap into a fuse panel IGN bussbar or whatever. You really need to have 1 central junction from which all of your devices pull power from and land that sense wire there too. This way, the gauge will read as fast as the alternators’ regulator reacts to changes in voltage fluctuations. As for soft start fan control harnesses using relays, they exist because I build them but a good DC Controls unit should be able to handle those Spal fans...even your DD controller should too...oftentimes the reliability of a fan controller is directly related to how well thought the installer made the process.
    DD gauges don’t have a dedicated voltmeter sense wire. They just read the power applied to the interface module.

    DD fan controller uses external customer supplied relays

    Don
    1969 Camaro - LSA 6L90E AME sub/IRS
    1957 Buick Caballero - huge project
    1959 El Camino - Ironworks frame
    1969 Mustang Sportsroof
    1956 Cameo - full C5 suspension/drivetrain

  6. #26
    Join Date
    Nov 2011
    Location
    Wylie, Texas
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    168
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    That's true but I would treat the constant power terminal of the DD gauge as if it was the voltage sense terminal and use a dedicated wire from the fuse block otherwise you do risk measuring the voltage drop of a wire that may be powering a high current device like the blower fan.

  7. #27
    Join Date
    Nov 2006
    Location
    Mountain Springs, Texas
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    3,069
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    Quote Originally Posted by blitzer454 View Post
    That's true but I would treat the constant power terminal of the DD gauge as if it was the voltage sense terminal and use a dedicated wire from the fuse block otherwise you do risk measuring the voltage drop of a wire that may be powering a high current device like the blower fan.
    Agreed. My goal was to prevent the OP from going crazy searching for his DD voltmeter sense wire...

    Don
    1969 Camaro - LSA 6L90E AME sub/IRS
    1957 Buick Caballero - huge project
    1959 El Camino - Ironworks frame
    1969 Mustang Sportsroof
    1956 Cameo - full C5 suspension/drivetrain

  8. #28
    Join Date
    Oct 2019
    Location
    PA
    Posts
    4
    Country Flag: United States
    My reply might be a little late, but I had the exact same thing happen with my setup. I'm using a SPAL fan setup with a relay. I'd be running 14 volts and the minute I turn on the fan, it would drop down to 12 volts or a little below.
    I found out my ground wire was way to small. I ran a 1/O awg wire from my - on my battery in my trunk, up to a grounding terminal which holds all my ground points for my components and then used the same size cable and grounded my motor to the chassis.
    Now I have a solid 14 volts at all times.



  9. #29
    Join Date
    May 2019
    Location
    Pensacola,Fl.
    Posts
    26
    I am going to be buying this serpentine setup soon and I don't think they offer a smaller alternator pulley anyway: https://www.cvfracing.com/stealth-bl...ic-water-pump/

    I would suggest you look elsewhere.....Yea nice folks to talk to.

    Lets see.....I broke a engine block due to their instructions being backwards. The stuff just doesn't line up well either.

  10. #30
    Join Date
    Sep 2016
    Location
    Bakersfield, CA
    Posts
    247
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    Quote Originally Posted by Warthog5 View Post
    I would suggest you look elsewhere.....Yea nice folks to talk to.

    Lets see.....I broke a engine block due to their instructions being backwards. The stuff just doesn't line up well either.
    That's certainly not good to hear. From what I can tell, they are the only game in town for an OEM looking serpentine setup on a Pontiac that supports an electric water pump...
    http://www.TheFOAT.com/92GTA
    1969 Pontiac Firebird
    w/BP 461ci stroker kit, 670 heads & XE274H cam. Primer black w/black interior.
    1992 Pontiac Trans Am GTA w/SLP Performance Package. Dark Jade Grey Metallic, grey leather, T-Tops.

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