High output alternator recommendations

[Dave_J]

Start at the basics.
1. CLEAN all connectors and ground points. If even 1 strand of the wire is broken at a connector, re-connector it with all strands in the connector.

2. Add a few new ground straps between the engine, frame, dash, gas tank and any other items.

3. Test for voltage drops.

4. UPGRADE wire sizes between all high draw items. The headlights should have been 14 Gauge but the factory used 18 gauge.
In 50+ years of high amp draws the copper has gotten smaller in true gauge, I measured my 65 B-cuda's at 20 gauge. I had been running 55w/100w H4 bulbs for 20+ years and the wires were always very warm.

5. REMOVE every Scotch Loc splice connector. My sons 74 D200 had 4 Scotch Loc's on the 10 gauge feed from the Amm meter and when I removed them, they had cut 7 strands of the 19 strands of the 10 gauge wire.

Anytime you upgrade the amperage output of the alternator you MUST do some mods to the Amm meter wiring. You can totally bypass it, not such a great idea, or do the partial bypass method of picking a large enough gauge wire to do a split load bypass like in the 'Taxi' system above. The higher the amp output, the larger the part load bypass gauge needs to be. Say you want a 120 Amp Altanator, the wire gauge need to allow 40 AMPs to flow thru the Amm meter and also let the remaining 80 Amps to bypass it.

Just as a note. If you go to a 1 wire alternator understand it gets its VOLT reading right at the field brush inside the alternator. If you have a major voltage drop in the wiring harness, the 1 wire alternator will not compensate as it still sees 14.5 volts inside. IMHO, a voltage regulator mounted on the firewall still gives the best true output. You can now get adjustable voltage regulators so you can turn a screw to raise or lower the voltage output.

 

[golden boy]

i ran the 1970 up(squareback) chrysler alt for years . you could buy these from rebuilders with ratings well over the advertised 60 amps. in fact you could rebuild your self using available parts to boost them to nearly 90 amps at one time. went thru 3 or 4 of these in the last ten years. seems like the duty cycle is too high as they wear out quickly. finally got smart and ordered one to fit a 89 mopar v8. rated at 120 amps it is the same Nippendenso that Toyota used with the internal regulator for years except this particular one is designed for the Mopar external electronic regulator and has the v belt pulley. seems to charge more at low rpm. nice part is its available at any parts store .

 

[Dave_J]

This was the BLUE 10 gauge wire coming from the Amm meter of my sons 1974 D200. It had those Scotch Loc's below for taps off for stereos and CB's. So all the amperage for the Fuse Box was being run thru the few unbroken strands. Notice the blackish color of over heating copper?

 

[70dart340]

I agree with pishta. If you have a quality DC amp clamp, you can turn on all the electrical loads, and get a good accurate amp reading load of your alternator/battery.

 

[zakimodo]

Another Powermaster recommendation. I had already rewired my car so the bulkhead wasn't a concern for me. I am using their 90 amp rated alternator with a similar setup to you. Sniper with the in tank pump (FBO ignition) and an electric fan. With the headlights and fan on at idle, the system is able to maintain charge.

 

[Dave_J]

I will say it one more time and this is not POO POO'ing on 1 wire Alternators as they are great if installed correctly.

A 1 Alt wire gets its voltage reading inside the alt. The OEM 3 wire gets its voltage reading at the factory voltage regulator and it will sense low volt in the system more in real world conditions.

But if the car/truck's wiring is the same old CRAP of smaller wire and rotten connectors the voltage drop at what ever is being powered may be REAL low and the 1 wire Alt will not read that.

So, if going to a 1 wire Alt, FIX the crap factory wiring and connectors......
If any one has a 50+ year old wiring harness that is in NOS condition, you have a small gold mine as it is worth a lot. Even the re-pop's are not real cheap and may not be 100% all there for all your needs.

And do not put a 90-120 Amp 1 wire Alt on a car/truck with a 35-40 Amp Alt and Amm meter without doing a Amm meter bypass.

 

[goldduster318]

I would personally recommend going to a Delco 12si alternator, you can buy one with 94 amps that was from a stock location and it has a single v-groove pulley. The brackets are easy, you flip the stock top one, cut off the lower leg, then you buy a GM universal one and weld it together to part of your original. Make a spacer.

For wiring, I would install this kit. It's overkill but its a good kit. You will want the squeeze crimper you use with a bench vise. I changed my car to a MIL spec positive cable and put another terminal on my B+ to the starter as well.
American Autowire 510475 American Autowire High-Output Alternator Connection Kits | Summit Racing

I have only a 78amp 12SI and this will run literally everything at idle (I have a contour fan, Aeromotive A340 Fuel pump, EFI computer) and maintain 12.5V at the dash gauge. That alternator is a basic parts store reman and has been on the car for over 10 years. I think I paid $55 back then. It's still a really low cost system, and if you need one on the road it shouldn't be much trouble to find one.

This was the thread from the original install.
How to: GM12SI alternator on a small block

 

[DrCharles]

I have a CS-130 (105 amp) that I got at a swapmeet for $25, figuring it was a core. Had it tested and it worked perfectly. It's been keeping the battery charged in my Dart for years (fuel pump, Contour fans, headlights, heater blower, etc.) and doesn't take up a lot of room, either.

 

[6pak]

The gauge of the wire from the alternator should be upgraded with any alternator upgrade over stock. Any connectors should be eliminated as I feel slip together connectors do not have the connecting surface area to pass the increased amperage.
Resistance = heat = burned up connections.
My opinion - your results may vary.

 

[70dart340]

The aircraft industry uses good, solid crimps over solder. NASA scientists found out in the early 1960's that solder joints tend to fracture under vibration. All the crimps I did on 747's and KC-46a's were done by the book, regarding wire size, gauge, and barrel type. The correct crimpers also were required. JMO.