do I need to update Alternator
Thread Starter
Instructor
Joined: Sep 2017
Posts: 100
Likes: 17
From: Sioux Falls SD
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
Racer
Joined: Sep 2001
Posts: 352
Likes: 51
From: Austin TX
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.
Melting Slicks
Joined: May 2012
Posts: 2,192
Likes: 343
From: Allenton Wisconsin
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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100 amps is usually more than enough. I have 100 amp with single dewitt fan, amp and subwoofer, and upgraded to halogen bulbs
Race Director
Joined: Apr 2007
Posts: 11,150
Likes: 890
From: South Western Ontario
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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Thread Starter
Instructor
Joined: Sep 2017
Posts: 100
Likes: 17
From: Sioux Falls SD
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; Jul 23, 2018 at 12:54 PM. Reason: spelling
Le Mans Master
Joined: Oct 2007
Posts: 7,445
Likes: 971
From: Tennessee/Rhode Island
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; Jul 23, 2018 at 01:17 PM.