Alternator Conversion: 12SI vs. CS130

Discussion in 'Interior/Electronics' started by Central Scrutinizer, Jan 11, 2012.

  1. Central Scrutinizer

    Central Scrutinizer Member

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    Hey guys

    My stock alternator just died, and I am having some trouble deciding what to do here, I have researched this thoroughly and need some advice. I have decided to convert to a 3 wire GM style alternator, I bought this kit. I have read that it will fit a CS130, or a 12si. I am trying to keep this fairly cheap, and would like to get as many amps as possible, while keeping it reliable. I will be running two compressors, and two audio amps (they are fused for 160 amps total), with no AC. I am not looking to constantly push the amps to the limit, just occasionally. Right now I have four options:

    1) Buy a 94 amp 12si for an 86 v8 buick regal (~$90), and this pigtail ($12). $102 total

    Pros: Cost, Availability
    Cons: Reliability? Enough amps? Remove factory harness

    2) Buy a 105 amp CS130 for an 88 v8 chevy caprice (~$75) and an adapter from alternator parts.com (~$30 shipped). I was told there were no CS style alternators that had V belts, it sure looks like a v belt in the pic...will this one work? $105 total

    Pros: Cost, Availability, Clean install
    Cons: Enough amps? Reliability? Correct Belt?

    3) Buy this HO alternator with this pigtail. This alternator was tested a few years back, and put out 100 amps at idle, 150 on the highway. $184 total

    Pros: Power, Reliability?
    Cons: Cost, Remove factory harness

    4) Buy this CS130 140A HO alternator ($162.99) with this adapter (~$30), and this pully ($7.99). $200.98 total

    Pros: Clean install, Reliability?
    Cons: Cost, Change pully

    Here are my questions:

    -Is the reliability of the 12si and the CS130 on par, or is one much better than the other?

    -Do I actually need more power, or will I be fine with one of the 100 amp options?

    -Am I missing anything? I would hate to buy these parts and find out something isn't compatible.

    Which route would you guys go?

    Thanks in advance :waytogo:
     
    Central Scrutinizer, Jan 11, 2012
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  3. TRUCK ACTION

    TRUCK ACTION Grand Toyotaholic

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    Read my post on the subject.
    I just went with a billet cased 12si, 150 amp,100 @ idle w/ a plug connector from the GM plug to my stock plug, keeping it 3 wire ,as want the charge lite.:cool:
     
    TRUCK ACTION, Jan 11, 2012
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  4. Central Scrutinizer

    Central Scrutinizer Member

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    HA, I got a good amount of info for the swap from your post! I was hoping you would respond, where did you buy your 12si from, and where did you get the plug?
     
    Central Scrutinizer, Jan 12, 2012
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  5. Litneon

    Litneon Super Moderator Staff Member

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    Two things to keep in mind when selecting the power rating of the alternator are, first - your audio system will rarely pull anywhere near the fuse value of the circuit, both amps together for a normal volume might pull 30-40 amps (might), and secondly - don't plan on using the full output of the alternator, maxing out the load can cause premature failure and over time, the load that the alternator can carry will go down.

    That being said, it's a balancing act. I have a Fluke clamp on amp probe that measures DC current. When I checked the load on my truck before changing alternators, I measured 47 amps at 13.7 volts. That was with the electric fan, a 185w x 4 RMS amp for the mids and highs, a 1200w RMS monoblock for the sub, the AZ OB2 compressor, and all of the lights running. The amps are both Jonah Lomu series Fusion Audio blocks that are class D efficiency.
    Turned up the audio system itself will pull about 200 amps +/-... This is why we have a battery, and I rarely turn it up that loud.
     
    Litneon, Jan 12, 2012
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  6. TRUCK ACTION

    TRUCK ACTION Grand Toyotaholic

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    Thought I had this in the original post.
    Any way here you go,got the alternator & plug from Quality Power,909-794-1600, $303.75.You can pull their site up.
    Good price & great service & shipping!
    I made a new top bracket & had to remake the spacer @ the lower bracket that fits into the alterator.
    All is working very well & looks killer! :cool:
     
    TRUCK ACTION, Jan 12, 2012
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  7. Central Scrutinizer

    Central Scrutinizer Member

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    That's a little more than I was looking to spend, I do agree it looks killer. I would love to keep this under 100, 150 tops.

    Liteon, sounds like a fairly similar amount of power I am going to need, what size did you go with?
     
    Central Scrutinizer, Jan 14, 2012
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  8. Central Scrutinizer

    Central Scrutinizer Member

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    And can anyone speak to the reliability of the CS vs the 12si?
     
    Central Scrutinizer, Jan 14, 2012
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