Another alternator upgrade thread

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340Duster247

340Duster247

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I know this has been beat to death , but I just can find the right answer.

I have a 71 duster with a square back alternator. I would like to upgrade it because I now have eletric fuel pump, 2 fans.....blah blah blah and the current amperage just ain't enough.

I wanna upgrade to around a 100amp , but what's the easiest way to do this? I already know I have to upgrade the wiring to batt. By bass amp meter. Ect.

What alternator do I purchase to replace this one.??....or is it easier to take my alternator to a shop and get it rebuilt (if that's even an option?) when I look online for alts. There just seems to be so many different options, so I wanna know what has work best for you guys with the least amount of headache.

Thanks
 
Do you want a stock looking or not?

Plenty of options.

Whatever you buy, make sure it has good charging capabilities at idle. Not the 1000 rpm lag point for most 70's stock mopar stuff.
 
I don't care what it looks like. I just want the easiest and most cost effective way.
 
If all your looking for is 100amps just get a new alternator from RockAuto. They have 100amp alternators for 64 bucks. Anything past 100amps its gets expensive.
 
You will have to upgrade the wiring bulkhead if you think you need 100 amp. Are you running a big stereo amp and extra lighting?
 
Yah as I said above....I already know and am going to upgrade the wiring (bulkhead ect. )
Just wanna know what alternator people are going with where it will fit without a headache. I don't wanna build new brackets or have fitment issues.
 
Both those write ups have great info. I checked rock auto, and the only ones I saw that are 100amps have external fans and don't say if there direct for or not. I've just read posts on here where others have purchased alts. And when they go to install they don't fit.

I'm running eletric fuel pump. 2 fans. Msd digital. mSD window switch. Solenoids. HID headlights. Gauges ect. Last summer the current alt could barley keep up and has now completely bit the bullet.
 
Just out of curiosity when you said your old/current alt couldn't keep up was that at idle or when cruising? Mopars are notorious for not charging at idle. Also, I suggested the ones at RockAuto because they say its a drop in replacement as was the alternator I was going to go with before I got a deal on a PowerMaster 140amp. I don't see why it wouldn't fit though....
 
At idle my lights would turn off.(hid) gauge lights so dim could barley see them.

So you went with a powermaster and it worked great?? Because that would be the answer right there I'm looking for. Do you have a part # or remember what one.
 
So right now at idle my LED head lights will flicker and my voltage at the cig lighter will drop to 12.2 volts or less. I changed the voltage regulator and that did help the upper end of my voltage probs (would go over 15volts while driving) but didn't help me when I was idling at a red light.

The 140 amp is the one I have sitting in a box right now. I haven't had a chance to instal it yet since its been snowing. My spring/summer project is to upgrade the electrical stuff, add an MSD box, bigger alternator and instal a stereo.
 
According to the box of my PowerMaster it should put out 80amps at idle and 140amps max while cruising. It is a one wire style so if looking factory matters it won't fit the bill. But I think you said your not worried about looking factory so if you can swing it the PowerMaster might be the answer.
 
Also my instructions do say the fan MAY interfere with the factory brackets but with some slit sanding on the bracket it will work fine. I would assume this would be the same problem with the 100amp from RockAuto.
 
340Duster247 said:
At idle my lights would turn off.(hid) gauge lights so dim could barley see them.
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I don't know about HID headlamps, but the gage lights getting real dim is a tip-off to other problems. Shouldn't everything run fine off the battery alone? Me-thinks you are getting high voltage drops thru corroded terminals and such. The alternators only job is to keep the battery charged, not provide all the load at idle.
 
Where in the system are your lights/pumps/etc... getting their power from? If it were me I would supply the respective relays directly off the output post on the alternator. That way the original wiring harness only has to carry switching and control loads.

Those Powermaster alternators look like CS series Delco units. Nothing wrong with that but I bet you could get a better price if you just buy a replacement part for an OEM application.
 
C130 Chief said:
Where in the system are your lights/pumps/etc... getting their power from? If it were me I would supply the respective relays directly off the output post on the alternator. That way the original wiring harness only has to carry switching and control loads.

Those Powermaster alternators look like CS series Delco units. Nothing wrong with that but I bet you could get a better price if you just buy a replacement part for an OEM application.
Click to expand...

I used a 130 amp gm 1 wire hanging under the pass. side elephant ear, works great.:coffee2:
 
charger426 said:
$102 isn't that bad. The $240 summit has it for now is crazy.
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What's 138$ in the course of your build?

I'd avoid the powermaster if I were you. I ran one in my last 440 dart and the mounting gave me some hassles. That tuff stuff is a true bolt in. Take yours out and put this one in. The one wire option is very nice too.
 
$138 is still $138 no matter where it goes lol Also, that toughstuff is $245 now...i'll pass of paying that price for the same output as a $65 one from RockAuto.
 
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