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Upgrading to powermaster 100amp alt

RobsRR

RobsRR

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So i did the mad electric mod on my 71 RR a few years ago. I now want more output at idle (added ac and elect. fan for condenser .) So now Upgrading alternator to powermaster 100 amp.
I used a 10 gauge wire as recommended in the mod. Powermaster calls for an 8 gauge up to 6 feet. Would you guys recommended redoing and replacing. I dont know if i will ever draw that much output?
 
This is the problem with this upgrade. YOU don’t think you need the wires To support The total amps, but you WANT a 100 amp alternator. Well the swap needs to be done completely. OR possibly meltdown the wiring. And then possibly the car burns up. Your choice.

When the regulator goes bad, when the battery goes bad, when a relay goes bad, when connections get high resistance, when something happens to make 80-90-100 amps and. You are unaware that’s when the wiring goes poof on you.

Just like using an ARP bolt and not following the torque numbers.

Why are you smarter than the people who made the parts?
 
And if your battery is not in its original position in the front, moved to the trunk?, you need to up the wire size further. Make sure you have good grounds and maybe add some too. The return path, ground, needs to be just as if not more burly.
 
Ok will do just wanted to be sure.
 
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re
 
I still find ppl miss the deal on this.

If you car sucks out 30, 40 or 50 amps, alternator will provide just 30, 40 or 50 amps no matter if 1000 amps capable. AMPS ARE NEVER PUSHED IN by the source, BUT SUCKED IN by the devices.

Don't you conect a 1.5 or 2 watts bulb ( 57 or similar ) with a 16 gauge wire to your 150 or 200 cranking power batt and nothing happens ? however you use a 4 or 2 gauge wire for the starter motor using the same battery!!!!

SOOOO... more than the alt output ratio against the wire thickness, think on what your car will suck out from it. I bet your car even with discharged batt won't need more than 50-60 amps ever. 70 just if batt is discharged and gets recharged while driving around ( and with A/C, lights on, wipers etc... )

the deal with high output alts is no more than get LOT of juice coming out from it while iddling to save from a discharged batt situation. For a while higher max output is the alt rate, this will be proportional at iddle
 
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Yes in retrospect that is what i was thinking too. So I think if you look at the diagram i posted it would be best to just upgrade the black wire from the alternator to the starter relay and the wire from the starter relay to the battery. I could go 8 gauge with a 12 gauge fusible link. Car is mostly stock batery in original location.
 
Where are you sourcing the fans? AC is not a problem. You won’t need more than 10 anywhere. 12 gauge fuse link will blow up when a big damage was already made. Don’t go bigger than 14.

But everything will depend on where you source the fans.

And I don’t like the MADelectrical job
 
Nacho-RT74 said:
Where are you sourcing the fans? AC is not a problem. You won’t need more than 10 anywhere. 12 gauge fuse link will blow up when a big damage was already made. Don’t go bigger than 14.

But everything will depend on where you source the fans.

And I don’t like the MADelectrical job
Click to expand...
 
The fan is sourcd at the starter relay and has its own relay. Wired on a temp switch comes on only with ac.
So I think you are saying not to change anything.
What dont you like about the mad electric mod?
 
If you source the fans straight from alt stud, won’t need a wire thicker than 10 running between alt and batt. I’m not saying you can’t run an 8 wire, just that is not really necesary even with a discharged batt because the power to the fans will be splitted of straight from the source. NOW, if you source the fans from batt or alt stud post, 8 is better, because in this case the power for the fan is running together with the power sourcing the rest of car and charge the batt when needed.

I bet fan wires are 14 or maybe even 16.

I don’t like MADelectrical mod because several reasons:

1- they say the main splice is being moved out of the cab, which is FALSE. They are just “replanning” an already existant junction point, but the main splice is unvariable still into the cab, feeding lights switch, fuse box, ign switch and getting the former ammeter wires.

2-they talk about the bulkhead and ammeter failures, but never explain certainly the REAL reason of those failures: a poor rated alternator output from factory (maybe they don’t know that either). Althought the bulkhead failure was to come sooner or later with a powerfull alt on black wire anyway, but more later than sooner.

Also the next reason for these failures is everybody sourcing INCORRECTLY all added accs to the batt post. That’s totally INCORRECT on cars with ammeter, but they don’t talk about that either! Just keep blaming underrated amms and bulkhead terminals.

So they blame the amm from the begining instead explain how really works and read the ammeter and fix whatever needed to be fixed. With the mod they post, the low rated alt is still there and you still will have a discharge status at iddle no matter what gauge you use, amm or voltmeter.

3-I’m a stockish guy AND at the same time I preffer an ammeter over a voltmeter.
 
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Nacho-RT74 said:
If you source the fans straight from alt stud, won’t need a wire thicker than 10 running between alt and batt. I’m not saying you can’t run an 8 wire, just that is not really necesary even with a discharged batt because the power to the fans will be splitted of straight from the source. NOW, if you source the fans from batt or alt stud post, 8 is better, because in this case the power for the fan is running together with the power sourcing the rest of car and charge the batt when needed.

I bet fan wires are 14 or maybe even 16.

I don’t like MADelectrical mod because several reasons:

1- they say the main splice is being moved out of the cab, which is FALSE. They are just “replanning” an already existant junction point, but the main splice is unvariable still into the cab, feeding lights switch, fuse box, ign switch and getting the former ammeter wires.

2-they talk about the bulkhead and ammeter failures, but never explain certainly the REAL reason of those failures: a poor rated alternator output from factory (maybe they don’t know that either). Althought the bulkhead failure was to come sooner or later with a powerfull alt on black wire anyway, but more later than sooner.

Also the next reason for these failures is everybody sourcing INCORRECTLY all added accs to the batt post. That’s totally INCORRECT on cars with ammeter, but they don’t talk about that either! Just keep blaming underrated amms and bulkhead terminals.

So they blame the amm from the begining instead explain how really works and read the ammeter and fix whatever needed to be fixed. With the mod they post, the low rated alt is still there and you still will have a discharge status at iddle no matter what gauge you use, amm or voltmeter.

3-I’m a stockish guy AND at the same time I preffer an ammeter over a voltmeter.
Click to expand...
 
1.So Nacho you make some good points. I think I will go to an 8 gauge wire from the alt. to the starter relay and from there to the battery. Given this don't I need to go with a #12 fusable link? If I dont then will there be any benefit in going to the heavy wire, #8. I certainly don't want to make it where if I do have an issue it cause some thing to burn up and go poof!
2. Did I see somewhere you posted a fix using relays so ac/heat blower wires at the fan switch don't get hot. If so can you share!
 
If you are already making the MAD mod but with 8 wire, you could get 12 fuse link to the main source as you thought but keep 16 running to the cab as they mention however I still preffer 14 fuse link even using 8 gauge wire. Try with 14 and if you get some problem ( which I highly doubt ) can upgrade it to 12 anytime.

Yes I used a 6 relay setup on my car all spreaded around into the cab and being sourced from the ammeter stud, alt side. These relays are low and high beams, low, mid and high AC blower speeds and Heater speed ( which is diff from the AC speeds ). Installed light relaus into the kick panel area, heater and high speeds around steering column area and low and mid speeds just over the AC box. Making this distribution what gets saves is the harness itself from being cut, but just removing the terminals from original plugs and using a jumper wire ( same color than the one installed ) to replace the one being removed. This make the relay upgrade invisible. Will search the pics and post

This the basic diagram what I can get deep into it if required:

relay upgrade underdash2.jpg


The deal is save the heat from blower speed switch ( their contacts are poor ) because on 73/74 this piece allways get heated able to melt the plug. Can't tell if is the same situation with 71/72s since switch on these is different. I'm searching the pic of how it looks the harness and the relays being hidded.
 
here is the job made ( same for all 3 locations )

pic one... how it looks the A/C harness, totally stock, uncut, same colors.

pic two... I pull out the harness abit and relays appear.

pic three... I run the 12 gauge red wire taking the power from amm. Used bullet kind terminals on each location to splice the power for each pair of relays. If I need another relay around, just cut the male end, add another wire for the new relay and attach a new male bullet end.

Relays are held up by the AC box bracket nut on firewall, same as the ground for them.

Sorry the low quality pics but were taken with an OLD Nokia 6275, way before the smartphones were a normal deal.
Imagen226a.jpg
Imagen227a.jpg
Imagen228a.jpg
 
The reason why the relay setup is spreaded in that way is because the max AC speed doesn't come from resistor box but straight from blower switch, so I decided to balance the load for the red wire feed all around making just ONE relay will be activated at the same time on each red end for the relays.

There is one exception on this, and is the blower low speed is BY DEFAULT allways ON as soon you turn on the AC. You can unplug the speed lever switch and the blower low speed will keep sourced ( at least on 73 and lates ) with just turn on the AC. This doesn't really matter selecting mid and high speed because by OHMs LAW the load will go throught the less resistance available. So you can select the mid speed and both relays on AC box area will be activated but actually just one of them getting the load to feed the blower with mid speed
 
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Wow thank you so much for your time to post all of this. My ac controller is out of a 73. Glad to know I am not the only one with hot fan blower wires. I will have to read your post several times and definitely would like to implement it.
 
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Modern cars are designed with the alternator power lead connected directly to the battery for a very good reason. This design doesn't just allows for the most amount of power to be delivered directly to the battery. This design uses the battery to act like a damper between the alternator and the rest of the car power system which will reduce AC whine and provide a cleaner DC signal.

Our old car were wired the way they were just for the ammeter. There's no special reason and the factory didn't care about clean DC power. It's not like they had to worry about digital radios and sensitive computers components.

Thus, the best thing to do is run an 4awg cable directly from the alternator to the battery, than 8awg from the battery to the starter relay. This will provide 200 amps to the battery and 80 amps to the car. The DC power will be clean and AC whine will be minimize. Doing this is an absolute must if you ever plan to install EFI or a good car audio system.

But... that is not factory looking at all. If you want a more factory look, I would recommend running no smaller than 8 awg wire from the alternator to the starter relay, and 8 awg from the relay to the battery. You will need a 12 or 14 awg fuseable link at the starter relay on the alternator wire. However, this will only support 80 amps to the car and 50 amps to the battery.

The down side is the DC power won't be very clean and you might gave an alternator whine in your speaker. But it will look factory. You could run a 6 awg wire instead of 8 awg but that would be hard to make it look factory. 6 awg cable would support 120 amps to the car, and 80 amps to the battery.

Also, one last thing. You want fine strands! Don't get that thick strand stuff for Autozone. Order cables from car audio place. You also want 100% pure copper. More strands more means more copper in the same about of space which can support more amps. The 4 awg I bought for my car has 1000+ copper strands that are thin as human hair.
 
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