High Output Alternator opinions

[Welder guy]

It uses the existing big block mopar alternator top bracket . The bottom adjustable bracket is a small block bracket. The pipe spacers over the top bolt fit pretty good, I had to modify one to get perfect belt alignment. It’s pretty easy to do. Get the side post alternator if possible. It keeps the power stud /cable and wires out of the way of the valve cover. I removed the wide multi groove-alternator pulley and put the older style single belt pulley on the alternator .

 

[Jengel451]

Had the Tuff Stuff alternator tested. all good. After more digging, the Tuff Stuff Alternator's are pretty much known for being crappy at Low RPM power generation and up until approximately 1200 engine RPM, they mimic OEM specs. Lesson learned on my end, hopefully this helps others.

 

[James Romano]

Had the Tuff Stuff alternator tested. all good. After more digging, the Tuff Stuff Alternator's are pretty much known for being crappy at Low RPM power generation and up until approximately 1200 engine RPM, they mimic OEM specs. Lesson learned on my end, hopefully this helps others.

I've had my share of issues like this... "oh yeah, it'll fit... oh yeah, its great...oh yeah, it's the best" and learned the hard way. Some of the aftermarket stuff is not the answer, modifying OEM sometimes is. Hence my original point of just doing the research, rather than ask for product opinions.

I find in the end, you're happier with you own decision.

 

[PursuitSpecial]

Have you tried using a stock 100A Leece-Neville alternator? Also, you need to ground the alternator and every other powered component on the vehicle with a cable as large as the hot wire as even an ohm or two between the alt and the engine bracket will cause nearly all current to be put through your ground wire. The stock bracketry on a Leece-Neville has enough surface area to do it alone but I would still run a ground.

 

[Milo]

I actually did. After a short chat with Power Master/ TuffStuff and a couple others I found out that in order to get the Mopar armature to spin fast enough I'd have to go down to a really really small pulley and that would make the High RPM range eat the alternator. That and since I'm running the CVF 8 rib. Nobody makes a smaller pulley.

I went down the rabbit hole on Mopar "Wye" windings compared to "Delta" windings of others and why Mopar cases have limitations.....broke me head a bit. Stock OEM setup, it's fine but once you try to make them do modern stuff, we have issues. Another reason why the Modern cars all have very similar looking Alternators, everyone learned.

You could put a small gear reduction in backwards to light that puppy up

 

[Jengel451]

Closing this out. The Powermaster GM SM10 is a beast. At idle it never once dips below 14.1 Volts with Fans and AC blower on High and Stereo going. The fans are working much much better now too, go figure what 2 missing volts will do.

It's advertised at 150 amps. The Dyno card they send with it shows it tested at 110A Idle/ 144A/Cruise and 164A Top End. The Sniper is much happier now too.

Again, this is using the the CVF conversion kit: Black Big Block Chrysler Serpentine Conversion, AC and Power Steering If you opt to go for it, just ditch the Mopar alternator and go with the GM SM10 setup and be done with it. Not to mention I was able to get rid of the Mopar Regulator and associated wiring so it's much cleaner now.

 

[furyusvip]

If you opt to go for it, just ditch the Mopar alternator and go with the GM SM10 setup and be done with it.

Great and timely information, as I have plans of upgrading my charging system. Do you remember the part number and/or have a picture of the new new alternator installed?

 

[Jengel451]

Great and timely information, as I have plans of upgrading my charging system. Do you remember the part number and/or have a picture of the new new alternator installed?

powermaster 57293

Better option but I couldn't use due to the 8 Rib pulley requirement: HPR (Small housing) Powermaster 847296-1 as cast, or 857296-1 Black. it's 180A (145A @ idle)

 

[UGW]

Been following this, since it relates to some upgrades I'm planning. I liked @Welder guy Dodge Dakota suggestion, but all the ones I found had a serpentine pulley. This got me thinking: the old Diplomat cop cars probably had a pretty beefy alternator. The M-body ran into the late 80s, but it was basically a 70s car. (It may be the last car sold in America with a carburetor) I looked it up on RockAuto, and sure enough, they have a 120A Denso alternator with a v-belt pulley and external regulation (3-wire). It's reman, but Denso usually doesn't suck. Seems like this could swap into an old Mopar pretty easily, but of course I haven't tried it.

 

[Big_John]

Been following this, since it relates to some upgrades I'm planning. I liked @Welder guy Dodge Dakota suggestion, but all the ones I found had a serpentine pulley. This got me thinking: the old Diplomat cop cars probably had a pretty beefy alternator. The M-body ran into the late 80s, but it was basically a 70s car. (It may be the last car sold in America with a carburetor) I looked it up on RockAuto, and sure enough, they have a 120A Denso alternator with a v-belt pulley and external regulation (3-wire). It's reman, but Denso usually doesn't suck. Seems like this could swap into an old Mopar pretty easily, but of course I haven't tried it.

View attachment 724932

I have a couple of those on my shelf with vee belt pulleys that I'd make you a smoking deal on. They were used ones that I bought and went through.

I bought one to try mounting in my '70 300. I had it figured out, then went another direction. I'm just trying to clean out some stuff that is laying around. PM me if you are interested.

 

[Gerald Morris]

Hey all, I've been running a Tuff Stuff 130amp alternator, but now that I have added Dual Fans I found its Achilles heal. Low RPM/Idle Charging (or lack thereof). Looking to switch to a GM 10 or 12SI unit.

The question: Who has the best Idle output that you've seen?

NOTE: I have already done all the re-wiring, 1ga feed direct to battery, 8ga Alt Ground. Relay 12v signal wire direct from Battery to regulator, bypass Amp Meter etc etc etc. I really don't need to be versed in what old Mopar did and why, just want honest opinions about GM 10/12SI manufacturers.

AC Car, Convertible Car
Aftermarket Stereo and Amp
Contour Dual fans (this is the one that pushed things over the edge)
Sniper Injection
Hyperspark Box
FI fuel pump
Group 27 AGM Battery (New)

In general, rough math is looking like I'd need somewhere around 95amps at 800 RPM Idle. Mopar Tuff Stuff Alternator is spinning at ~2200 rpm. When sitting in traffic at idle with everything going, it's dropping below 12v until about 1500 engine RPM's then it comes up. Regulator is good, swapped in 3 new ones and all had identical behavior so I know the Alternator isn't up to task at Low RPM.

EDIT: Looking at this Alternator. Seems to have the exact same mounting as the 10/12SI. 145amps output at Idle.
Powermaster 857296-1 Powermaster HPR Small Frame Series Alternators | Summit Racing

Powermaster DEFINITELY kicks in the high current WELL before 1500 rpm bro! Get one. I suppose if you've already committed to modernizing your ride too far, the GM alt will have to do, but you're AWARE that Powermaster makes high current stuff more Mopar-friendly, right? Their 57539 line is rated for 200 amps, and is Old Chrysler friendly enough. My Powermasters kick in just over idle, like, 800 rpm, giving me 14.7 VDC without me loading them with the pusher fan, headlights and defroster fan on high. Mine is only rated at 95 amps, but serves very well.

I'm NOT impressed with (None-too-)Tuff Stuff, after one of their starters bellied up on me in 13 months. I recently got it to spin again, but won't trust it for an actual family vehicle ever again.

 

[Gerald Morris]

Been following this, since it relates to some upgrades I'm planning. I liked @Welder guy Dodge Dakota suggestion, but all the ones I found had a serpentine pulley. This got me thinking: the old Diplomat cop cars probably had a pretty beefy alternator. The M-body ran into the late 80s, but it was basically a 70s car. (It may be the last car sold in America with a carburetor) I looked it up on RockAuto, and sure enough, they have a 120A Denso alternator with a v-belt pulley and external regulation (3-wire). It's reman, but Denso usually doesn't suck. Seems like this could swap into an old Mopar pretty easily, but of course I haven't tried it.

Read some hacks for getting that Denso working w Old Mopars. Supposedly pretty easy, but I'm lazy, and like my Powermasters....