What are you folks using for a high outout alternator in your hotrods?

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Jeremiah (jd) said:
I have bypassed the ammeter. In addition, there's a 12 circuit fuse panel with multiple relays under the battery tray. Only the interior lights, turn signals, brake lights and dome light go through the bulkhead connector.

I have the following electrical components to feed:

N20 solenoids
N20 progressive
MSD 7AL2
O2 sensors/AFR meters
Dual electric fans
340 LPH fuel pump
(Future) electric water pump
Electric exhaust cutouts
(Future) EFI ecu
(Future) EFI dash
Lights
Line lock

I'm thinking 130-165A should be plenty. I'm leaning towards this:

Powermaster 8-68529-116 Powermaster Street Alternators | Summit Racing
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I am running that same alternator in my car. If I had it to do over again I would probably go dual groove pulleys as it gets squealy at times with bigger draws and the belt is about as tight as I like it. In addition to the fans, fuel pump etc. I have to have a stereo in my street/strip car to remind me of the "real" street racing days.
 
lead69 said:
I am running that same alternator in my car. If I had it to do over again I would probably go dual groove pulleys as it gets squealy at times with bigger draws and the belt is about as tight as I like it. In addition to the fans, fuel pump etc. I have to have a stereo in my street/strip car to remind me of the "real" street racing days.
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Luckily I have not had that issue. I had an 8 track hooked up for a while until I realized I was bored with most every genre of music aside from a well tuned v8. As far as tension is conceened, I'd like a repeatable, affordable method of checking belt tension.
 
Just installed this one.
www.summitracing.com

Powermaster 8-38529-116 Powermaster Street Alternators | Summit Racing

Free Shipping - Powermaster Street Alternators with qualifying orders of $109. Shop Alternators and Generators at Summit Racing.
www.summitracing.com www.summitracing.com

20250529_150652.jpg
 
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Jeremiah (jd) said:
Luckily I have not had that issue. I had an 8 track hooked up for a while until I realized I was bored with most every genre of music aside from a well tuned v8. As far as tension is conceened, I'd like a repeatable, affordable method of checking belt tension.
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Are you not having slipping issues with the 95amp or the 165amp?, I am running the 165amp on mine. Agree on the belt tension, of course I think the quality of belts (and most all rubber products) now days are crap lol.
 
lead69 said:
Are you not having slipping issues with the 95amp or the 165amp?, I am running the 165amp on mine. Agree on the belt tension, of course I think the quality of belts (and most all rubber products) now days are crap lol.
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95A, sorry my brain wasn't firing on all eight last night. We have the big cruise this weekend so my shop has been very hectic with last minute fixes so everybody can go full fonzi in town this weekend. I agree with your assessment concerning rubber products.
 
lead69 said:
I am running the 165amp on mine.
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Can I ask why? surely 120 would be more than enough to power any ignition and accessories you may use.
I can operate a snowplow all day with heater and stereo on without a hiccup on subzero days with a 160 amp and good battery.
Are you operating a snowplow. lol
 
71Demon540 said:
Powermaster 150 amp 1 wire
13.5-18.5 volts adjustable regulator. 8148 part number. Puts out I think 60-65amps at idle and little over 150 full throttle. Not that it ever needs that many amps. But the smaller units don’t charge enough at idle to do the job.

I run a 16v battery so I have it turned up to 18.5 volts. Charges great. I don’t need to charge at the track on race days.
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This is a relevant point! I pullied the alternator so it's at maximum recommended RPM at my trap RPM. This way it has a decent but barely adequate 'idle' charging output. But then my trap was high @ 8200 engine speed.
 
My 95 amp provides I believe 65 amps at idle.
Between fan and water pump( roughly 30 amps) spark box and fuel pump maybe another 10 amps, it’s proven to be more than adequate.
The key is making sure whatever alternator you run, that the unit is getting excited at a level that isn’t below what your idle rpm is. Otherwise obviously you will kill the battery over time.
I am just now getting to the point the single interstate battery I bought 7 years ago is probably not as stout as it was and needs changing.
 
Most alternators worth a **** should come with a charge graph to show how much current it produces at various RPMs. Here's the one that came with my Bosch 90A denso style alternator. Keep in mind the RPMs on these graphs reflect alternator RPM, not engine RPM.

1749916296293.png
 
A smaller pulley size on the alternator will increase charging output at low speed.
We did this little trick a few times
 
fishmens67 said:
A smaller pulley size on the alternator will increase charging output at low speed.
We did this little trick a few times
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Problem is a lot of the Mopar style alternators the pulley is a pin on deal and a royal pain to get off, or designed to come off
 
fishmens67 said:
Can I ask why? surely 120 would be more than enough to power any ignition and accessories you may use.
I can operate a snowplow all day with heater and stereo on without a hiccup on subzero days with a 160 amp and good battery.
Are you operating a snowplow. lol
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No lol, I went with what several shops recommended since I have quite a bit of amp draw from the fans/accessories etc and then there is the future nitrous setup. The potential exists for being close to maximum output with 120 amp max rated alternator at idle and I like to have room.
 
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B3422w5 said:
Can’t imagine needing more than 100 amps unless you have some huge booming stereo system onboard with big subs or something
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Clearly you didn't see this thread.

60A, straight-up, in addition to everything else in the car. At least when it's hot out.

Actually looks interesting. If there's a spot to put the condenser under the rear of the car, you could put all of the components in the trunk and route cold air through vents in the package shelf, and make a near-invisible installation.

– Eric
 
B3422w5 said:
Can’t imagine needing more than 100 amps unless you have some huge booming stereo system onboard with big subs or something
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A 165 amp puts out around 100 at idle where as a 100 amp alternator typically puts out around 60 amps. Cruising with everything on at night my car would be right at the limit with 60 amps at idle.
 
I had my entire car rewired a few years ago and it was set up to use a one wire alternator , I am using a Powermaster 90 amp part # 75191 as a matter of fact I just had to replace it with a new one . I took the bad one to a rebuilder it be redone to use as a spare and he said he couldn't because evidently the main shaft is machined just for their bearing size and nobody makes a replacement: in other words it would cost more to rebuild it than a new one would cost.

IMG_1126.jpeg
 

Thanks for the additional info.

Now you have me wondering if I should have a snow plow LOL

I called powermaster and asked them if they would rebuild my alternator that is not putting out any juice. They said go ahead and send it in with all of my information and they would hit me up with an RMA number and cost to rebuild it. I'll let you guys know how that process works out.

I dug out the original test cars for my 95A powermaster

Lastly....daaaaaamn you guys have cool cars!!! Keep the pictures coming!

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