bypassing / eliminating factory voltage regulator

Electrical & Ignition

  1. multimopes

    multimopes FBBO Gold Member FBBO Gold Member

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    I want to install an internally regulated alternator that will put out enough voltage at idle to run 2 heavy draw electric cooling fans and any other items like lights, etc. What does one do with the old field wires and voltage regulator wires?? I have seen someone here who did this and left dummy wires going to the old regulator so it didn't leave a void on the firewall. I personally don't care so much about pretty, just functionality. I called Summit to ask about it while looking at Power Master Alts but they didn't know. I did a search for this here and came up with other similar remedies but no soap otherwise. Do the new internally regulated alternators come with instructions on how to do this?? Any help would be appreciated. :)
     
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    • pnora

      pnora FBBO Gold Member FBBO Gold Member

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      I would trim the connectors, open the harness and tape the wires into the harness. You can plug the holes multiple ways.
       
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      • 1 Wild R/T

        1 Wild R/T FBBO Gold Member FBBO Gold Member

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        The regulator & wires attached to it can be eliminated.... The Green wire goes from the regulator to the alternator, it grounds the field... Internally regulated doesn't need it... The blue wire to the regulator is keyed power so it needs to be isolated/insulated from any potential grounds... The blue field wire is also keyed power & will be used to apply switched power to the new alternator.... And the large black wire going to the battery post of the alternator will possibly still be used to carry power from the alternator to the battery... Accept it goes through the bulkhead connector twice plus through the Ammeter... So it has potential for causing allot of problems... Personally I add leave it but add a second 8 ga wire from the battery post of the alternator to the battery post of the starter relay... You should add a 10 ga fusible link to that wire near the battery..
         
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        • threewood

          threewood FBBO Gold Member FBBO Gold Member

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          I just went through this. Installed a Denso alternator. I dummied out the original voltage regulator by welding the connections together and epoxy welding them to an isolator on the vr body.

          Original green wire was reused as was the bolt on alt wire. The only add on was a wire for battery sense (blue) which goes right to the battery.

          Worked great. Mine is 60a and it holds 14.3v at idle, lights on.
          20210104_150811.jpg 20210104_151133.jpg 20210104_160120.jpg 20210104_153306.jpg
           
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          • threewood

            threewood FBBO Gold Member FBBO Gold Member

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            Screenshot_20201227-103550_Chrome.jpg

            Ign = green field wire
            Lamp = not used
            Sense = added blue wire to battery
             
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            • 1 Wild R/T

              1 Wild R/T FBBO Gold Member FBBO Gold Member

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              Okay, yours is a early (69 & older) design so it switches power to the alternator & the alternator field is internally grounded

              The O/P appears to have a late (70 & newer) design that switches the ground through the green wire...
               
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              • threewood

                threewood FBBO Gold Member FBBO Gold Member

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                I'm in for the answer too then. I didn't know they were that different.
                 
              • pnora

                pnora FBBO Gold Member FBBO Gold Member

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                My Power Master has just one wire. The battery wire.
                 
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                • 1 Wild R/T

                  1 Wild R/T FBBO Gold Member FBBO Gold Member

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                  I really don't care for that design... They use an RPM activated switch to excite the field windings... Seen to many fail, I'd much rather have a switched power wire trigger... Especially since there's a suitable wire right there...
                   
                • multimopes

                  multimopes FBBO Gold Member FBBO Gold Member

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                  What internally regulated alternator would you recommend? I like the Power Master ones, look like stock! I was looking at a 75091 on Summit, 95 amp dual pulley.
                   
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                  1 Wild R/T FBBO Gold Member FBBO Gold Member

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                  Powermaster doesn't seem to have any info about that pt# on their website & Summit which usually has a link to the instructions doesn't... Took some looking around but they list that pt # as one wire "capable" which points to it having an RPM switch... On their website they say some of their alternators that are one wire capable are also capable of being triggered by a switched power connection... But I couldn't find anywhere that the 75091 # was mentioned.... No idea... Power Master has a reputation of good customer service you could try calling or emailing...
                   
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                  • multimopes

                    multimopes FBBO Gold Member FBBO Gold Member

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                    Thank you very much for helping me out with this. I had to bug out last night as it was the end of my shift. I got to thinking if there is a Mopar style of alt that puts out enough juice at idle to just keep my factory voltage regulator, I could just do that instead. I have seen the videos of people mounting a small regulator on the outside of the alternator but if the alt doesn't have the capacity at at idle, what's the point? I will be calling Power Master to see what the specs are and what they recommend.
                     
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                    • 72RoadrunnerGTX

                      72RoadrunnerGTX FBBO Gold Member FBBO Gold Member

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                      Why the push to dich the external regulator? There are just as many, if not more, high-capacity OE style isolated field alternator replacement options available as there are internal regulated versions. Check out Tuff Stuff Performance.
                       
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                      • multimopes

                        multimopes FBBO Gold Member FBBO Gold Member

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                        It's not totally necessary to ditch it if it will indeed handle a high load at idle, and I understand that it might be able to. But, according to what I read in the fairly recent past the newer regulars react better. In my post 12 above I stated that. I will check out the "tuff stuff' link as you provided thank you! I am still open to suggestion, up to and including a self installing unit that also makes me beer, LOL. :D
                         
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                        • 72RoadrunnerGTX

                          72RoadrunnerGTX FBBO Gold Member FBBO Gold Member

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                          The voltage regulator has nothing to do with the alternator output capacity. The regulator only sees field current in it's job to maintain a set voltage. You can run any regulator you want with higher output alts. I run a OE reproduction regulators with 130amp alts.
                          I’ve also run Tuff Stuff’s OE external regulator replacement as well as voltage adjustable aftermarket regs.
                           
                          Last edited: Apr 6, 2021
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                          • multimopes

                            multimopes FBBO Gold Member FBBO Gold Member

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                            I thank you sir, I just got off the phone with Tuff Stuff and am ready to purchase a direct (old style) replacement using my original VR. I thank all of you guys for helping me out here on the best Mopar site there is!
                            :thumbsup:
                             
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                            • 383man

                              383man Well-Known Member

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                              Most one wire alt's that I have read about self excite from the magnatism in the rotor once they start turning and then they build up output until the internal reg takes control of the field. I have not heard of an rpm activated switch ? Actually the more I think about it I guess it makes sense as since the rotor self excites and starts trying to put out current maybe the internal reg needs to see so many rpm from the rotor to start controlling the field ? Never really thought about it that way as I just assumed as soon as the field current started flowing when the rotor starts turning the reg would just start to control it. Does kinda make sense for a type of rpm switch in the reg ? I will say I have used two of the Power Master one wire Mopar alt's on my boys car and mine. Its the alt that is a Mopar style alt and I had a problem with the reg going bad after about 6 months on my car. They replaced it and it been fine for about 6 months so far and my sons has been on his car for 2 years and still working good. You can see on this Mopar one they actually send volts to a brush from the reg as one brush is grounded and the other hooked to a wire from the internal reg. When mine stop charging I took the wire from the int reg off the brush it went too and jumped 12 volts to that brush and she went right up to 16 volts and climbing. I was actually going to just isolate both brushes and wire an ext reg to it if they did not warranty it but they did with no problem. Ron
                               
                              Last edited: Apr 10, 2021
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                              • JDmac72chrgr

                                JDmac72chrgr Well-Known Member

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                                multmopes, did you "bypass" the dash "voltmeter/ampmeter" in the engine bay? If no, that my be an idea to lessen voltage drops. Check bulkhead harness for ANY signs of damaged/brittle wires. Common issue if original bulkhead block.
                                 
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                                • multimopes

                                  multimopes FBBO Gold Member FBBO Gold Member

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                                  The bulkhead connection for the amp meter was disconnected before I bought the car. It had a standalone panel with Sunpro gauges for volts, oil pressure, and temperature. All were home runs to the engine. Half of my original cluster gauges were disconnected and still are. The only working ones are speedometer and fuel. As the car was stripped for racing, a big ass tach was mounted on the top of the dash. I have added a vacuum gauge, oil temp and trans temp. also under the dash. Adding insult to injury, my battery is in the trunk!
                                  Meanwhile, back at the ranch; I received the new 130 amp Tuff Stuff alternator and installed it yesterday. Bad news, it doesn't do what they claimed. It is virtually the same as the 95 amp Power Master it replaced. At idle, it is 14.3 volts or so; one fan on drops it to 13 or slightly less and 2 fans to 11 volts. I even increased the idle from around 800 to 1050 and still no soap. It charges both very nicely at about 1300 rpms. Per the instructions and warranty, I had to add a separate 10 gauge ground from the case to the engine. After all my grand expectations and $200.00 later, same sh_t , different day! I will call them on Monday to see what they say. I will most likely need a self regulating alt from somewhere else and bypass the factory style regulator. I was told from several sources the the factory reg. will do the job and that the underlying problem is the fact that the alternator(s) don't have the snot at idle to do the job. :(:BangHead:
                                   
                                  Last edited: Apr 10, 2021
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                                  • MarPar

                                    MarPar If it weighs, it pays FBBO Gold Member

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