do I need to update Alternator
#1
Instructor
Thread Starter
do I need to update Alternator
I have a 75 C3 that I'm currently replacing the L48 with a 383 motor. I have a Dewitt dual electric fan setup coming and I was wondering if my stock alternator will keep up with it 's charging duties. If not what amp would I need in it's place. Thanks John
#2
Race Director
Take alt or car to get it output tested. Check numbers on alt to see if it is orig to car. Most rebuilts and aftermarket are higher output already.
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gmcman52 (07-23-2018)
#3
CS144 Alt
I would think we soon as you go electric fans, the original 60 (?) amp alternator is going to struggle. Add in headlights and I'd think battery would run down quick.
An easy and cheap swap is a CS144 alternator. Here is a write-up of my install with a minor problem i overcame. Very little invested in this upgrade and definitely happy with the final results. I swapped the alternator because I was fol!owing it up with a fuel injection install. Putting in electric fans soon so have plenty of power available.
An easy and cheap swap is a CS144 alternator. Here is a write-up of my install with a minor problem i overcame. Very little invested in this upgrade and definitely happy with the final results. I swapped the alternator because I was fol!owing it up with a fuel injection install. Putting in electric fans soon so have plenty of power available.
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gmcman52 (07-23-2018)
#4
Melting Slicks
I agree with Matt about the CS style of alternator upgrade, I didn't read his post but if the large wire on your alternator is only 12 gauge putting in excess of more than 100 amps isn't going to last. T
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gmcman52 (07-23-2018)
#5
Race Director
And if alternator is original, either keep it or sell it in the parts section here. DO NOT turn it in for a 5 to 20 buck core...
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gmcman52 (07-23-2018)
#6
Dementer sole survivor
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100 amps is usually more than enough. I have 100 amp with single dewitt fan, amp and subwoofer, and upgraded to halogen bulbs
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gmcman52 (07-23-2018)
#7
Just go to the CS-144. You'll be happier.
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gmcman52 (07-23-2018)
#8
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You 100% need a bigger alternator. Go CS130D or CS144. Upgrade the charging wires to 6 gauge.
Do no try to use a C5 style alternator. It's connects to the PCM and is specific to a C5.
I personally wouldn't bother with any of the increased current 10SI versions because they still have the same limitations (cooling & idle current) that the stock 10SI alternators have.
Do no try to use a C5 style alternator. It's connects to the PCM and is specific to a C5.
I personally wouldn't bother with any of the increased current 10SI versions because they still have the same limitations (cooling & idle current) that the stock 10SI alternators have.
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gmcman52 (07-23-2018)
#9
Instructor
Thread Starter
Thanks guys for all the reply's. The alt is the orig 63 amp that I rebuilt some of the inner works in the 90's
Last edited by gmcman52; 07-23-2018 at 12:54 PM. Reason: spelling
#10
Le Mans Master
CS 144-140 Amp stock amperage alternator. Run a 6 gauge welders wire with an in line high amp fuse from the Bat terminal on the CS144 alternator along side the stock bat terminal wire to the starter. The starter to battery wire on my 78 is sufficient to handle a 140 amp alternator easily.
Last edited by jb78L-82; 07-23-2018 at 01:17 PM.
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gmcman52 (07-23-2018)