New alternator and mad mod question

[Sonny]

‘70 Belvedere 440. No ac, stock AM radio, no power windows or seats, mech fuel pump.
All new stock wiring harnesses.

1. I am running 2 12” electric fans pulling about 17 amps each. I’m pulling power straight from the alternator stud to the fans thru breakers and relays. Stock alternator at 65 amps max., but at idle with fans on voltmeter reads 11 or so. Lights on it’s even worse. Back to 12-14 volts cruising.

2. Considering upgrading my alternator to powermaster 95 amp (65 amp at idle). Also going 1 wire alternator and removing Mopar VR and both field wires. Which leads to question #3 below:

3. Should I do “Mad Mod” and upgrade wire from alternator to stater relay to 8 gauge wire? (I already bypassed the ammeter). “Or” with fans powered straight from alternator should I leave stock harness as is and just add alt and remove stock VR?
Thanks!

 

[Frankb]

No do not do the Mad Mod. Yes run the big wire from alt to starter relay or directly to battery. 8 gauge is fine. 6 is better. I did mine to start relay. You are correct to run fan power directly from alt. Another way would be to run 6 gauge wire from alt to a power distribution buss. This gives you options if you elect to add more electrical components in the future. You can only add so many terminals to the alt before things get tight.
Frank

 

[Sonny]

No do not do the Mad Mod. Yes run the big wire from alt to starter relay or directly to battery. 8 gauge is fine. 6 is better. I did mine to start relay. You are correct to run fan power directly from alt. Another way would be to run 6 gauge wire from alt to a power distribution buss. This gives you options if you elect to add more electrical components in the future. You can only add so many terminals to the alt before things get tight.
Frank

Thanks! So leave the smaller stock black wire from alternator to bulkhead connector as is(connected)?

 

[Nacho-RT74]

Well on the first instance I wouldn't bypass the ammeter, but after say that and since you already decided it, in your case this is what I would do:

On this setup, I would feed the fans relays either from firewall junction or alt stud

 

[Sonny]

Well on the first instance I wouldn't bypass the ammeter, but after say that and since you already decided it, in your case this is what I would do:

View attachment 957889

On this setup, I would feed the fans relays either from firewall junction or alt stud

Thanks!

 

[Fran Blacker]

Nacho are the green lines on alternator grounds?

 

[Nacho-RT74]

You mean on diagram? nah, thats because I constantly edit same diagram and didn't deleted completelly. I don't specify what kind of alternator do you have on diagram ( although it comes from a dual field alst diagram I made ), just show the output wire. Being single wire, ( internal regulator ), single or dual field, the wiring between alt and batt ( and ammeter ) gets the same setup.

 

[matthon]

What I did in a nutshell.
New wire directly from alt to starter relay with a fusable link.
Remove original black wire going alt to bulkhead, note where it is plugged into bulkhead.
Disconnect ammeter and terminate red wire (I did this on one car, my other iirc the power seat was connected to the black side so I just spliced those two together).
Take original red wire from starter relay, remove from bulkhead, connect to where the original black alt wire was connected.

 

[Nacho-RT74]

Oh, and BTW... you can leave the existant wiring on engine harness ( VR and stock alt output wire ), just not use them right now. You don't know if will be useable later. Isolate the ends and done.

getting the firewall juntion will get you power buss for both sides of firewall

 

[Sonny]

Oh, and BTW... you can leave the existant wiring on engine harness ( VR and stock alt output wire ), just not use them right now. You don't know if will be useable later. Isolate the ends and done.

getting the firewall juntion will get you power buss for both sides of firewall

I’m planning on repurposing the blue VR wire for switched power to my fan relay. Currently stealing power from my windshield wiper motor

 

[rrTor-Red]

‘70 Belvedere 440. No ac, stock AM radio, no power windows or seats, mech fuel pump.
All new stock wiring harnesses.

1. I am running 2 12” electric fans pulling about 17 amps each. I’m pulling power straight from the alternator stud to the fans thru breakers and relays. Stock alternator at 65 amps max., but at idle with fans on voltmeter reads 11 or so. Lights on it’s even worse. Back to 12-14 volts cruising.

2. Considering upgrading my alternator to powermaster 95 amp (65 amp at idle). Also going 1 wire alternator and removing Mopar VR and both field wires. Which leads to question #3 below:

3. Should I do “Mad Mod” and upgrade wire from alternator to stater relay to 8 gauge wire? (I already bypassed the ammeter). “Or” with fans powered straight from alternator should I leave stock harness as is and just add alt and remove stock VR?
Thanks!

You need to get a hold of member 'crackedback'. He makes a harness that will be beneficial to you. DO NOT DUE THE MAD electrical, it just looks like a hack job

 

[Sonny]

Attached is the diagram I modified with my plan. Does this look correct? How does splice #1 get power now that the blue wire from the VR is removed?

 

[Sonny]

Attached is the diagram I modified with my plan. Does this look correct? How does splice #1 get power now that the blue wire from the VR is removed? View attachment 961305

Note I was going to take the red wire from ammeter and use it to power my gauge pod. Ammeter is bypassed.

 

[Nacho-RT74]

I preffer to bypass the bulkhead before the ammeter! Bulkhead is the weakest point of the system allong with the pooorly rated alternators installed from factory, not the ammeter.

use the old amm red wire to feed the gauge pod ? but from where ? you need a switched source for them, if now will be sucking power allways

 

[Sonny]

I preffer to bypass the bulkhead before the ammeter! Bulkhead is the weakest point of the system allong with the pooorly rated alternators installed from factory, not the ammeter.

use the old amm red wire to feed the gauge pod ? but from where ? you need a switched source for them, if now will be sucking power allways

Thanks for responding.
Since I was going to remove the original black alt feed wire, I was going to move the 14ga link (that attaches to starter relay) from its bulkhead slot to the old alt feed wire bulkhead slot to power the wires under the dash. Then, remove old ammeter red wire from bulk connector and run it to feed my aftermarket gauge pod basically making a dead end harness out of the old ammeter wires. No?

 

[Sonny]

Thanks for responding.
Since I was going to remove the original black alt feed wire, I was going to move the 14ga link (that attaches to starter relay) from its bulkhead slot to the old alt feed wire bulkhead slot to power the wires under the dash. Then, remove old ammeter red wire from bulk connector and run it to feed my aftermarket gauge pod basically making a dead end harness out of the old ammeter wires. No?

sorry, I meant completely remove red ammeter wire then use black ammeter wire end (that was on ammeter) to power gauge pod (volt meter and temp).

 

[Nacho-RT74]

Thanks for responding.
Since I was going to remove the original black alt feed wire, I was going to move the 14ga link (that attaches to starter relay) from its bulkhead slot to the old alt feed wire bulkhead slot to power the wires under the dash. Then, remove old ammeter red wire from bulk connector and run it to feed my aftermarket gauge pod basically making a dead end harness out of the old ammeter wires. No?

Can you ? yes, is posible. Will require to use a fuse link on the line coming out from alt to starter relay as I think you already shown on diagram to protec that section, and, well the existant fuse link will be reused to protect the cab being linked to the black side of the wiring to feed the main splice.

but as I mentioned, you are keeping the weaker part of the system which is not the ammeter as everybody thinks but the bulkhead. Is true you are saving the Charge/discharge process from bulkhead BUT all the load the car requires is still going by the bulkhead, this time just by one ( previouslly two, the batt and the alt ones ) . You don't have A/C but I guess you have still heater, so the blower is sucking throught that only path, same as headlights, wipers... sure they are not usually working at the same time, but if comes the case, you'll find how the bulkhead affects.

You can try it anyway... if you find later some lack of power you can make the change later without problem

Are you thinking on use relays also for headlights ?

the red wire... well as the diagram I made, if you keep it and get all the wires together, the main splice will be feeded by two paths, the red and the black one.

 

[Nacho-RT74]

sorry, I meant completely remove red ammeter wire then use black ammeter wire end (that was on ammeter) to power gauge pod (volt meter and temp).

the pods require switched sources... either black or red wires arriving to ammeter are originally a batt source ( unswitched ) what would mean the gauges pod will be sucking power constantly. Not a big load, actually minimal thought, but still sucking. You need a switched source for them.

if you think on try to reuse the red wire ( or also the black wire ) originally running to ammeter to feed gauges pod will require to remove the red wire completelly from the Harness and reroute it. Doesn't worth the effort, just use a new wire from whichever switched source you plan on use.

Also if you think on use the black wire end originally arriving to ammeter, will be hot all the time, is still a batt source, not switched, so the pods will never turn off either

 

[Sonny]

the pods require switched sources... either black or red wires arriving to ammeter are originally a batt source ( unswitched ) what would mean the gauges pod will be sucking power constantly. Not a big load, actually minimal thought, but still sucking. You need a switched source for them.

if you think on try to reuse the red wire ( or also the black wire ) originally running to ammeter to feed gauges pod will require to remove the red wire completelly from the Harness and reroute it. Doesn't worth the effort, just use a new wire from whichever switched source you plan on use.

Also if you think on use the black wire end originally arriving to ammeter, will be hot all the time, is still a batt source, not switched, so the pods will never turn off either

Thanks Nacho. Forgot about switched power. I have my gauge pod getting power from switched fuse box tab now. I’ll just leave it there. I was just looking for a safe place to terminate the black wire from ammeter. Guess I’ll heat shrink that terminal end, roll up, and secure safely.
Sonny

 

[Sonny]

Can you ? yes, is posible. Will require to use a fuse link on the line coming out from alt to starter relay as I think you already shown on diagram to protec that section, and, well the existant fuse link will be reused to protect the cab being linked to the black side of the wiring to feed the main splice.

but as I mentioned, you are keeping the weaker part of the system which is not the ammeter as everybody thinks but the bulkhead. Is true you are saving the Charge/discharge process from bulkhead BUT all the load the car requires is still going by the bulkhead, this time just by one ( previouslly two, the batt and the alt ones ) . You don't have A/C but I guess you have still heater, so the blower is sucking throught that only path, same as headlights, wipers... sure they are not usually working at the same time, but if comes the case, you'll find how the bulkhead affects.

You can try it anyway... if you find later some lack of power you can make the change later without problem

Are you thinking on use relays also for headlights ?

the red wire... well as the diagram I made, if you keep it and get all the wires together, the main splice will be feeded by two paths, the red and the black one.

No on the headlights. Didn’t think about that. I live in Florida so don’t use the heat, no ac, now power windows or seats, just stock am radio! With fans hooked to alternator, system should take the normal low beams ok with fans on you think?