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new alternator

Discussion in 'GM Electrical Tech' started by reggiecab2000, May 1, 2012.

  1. reggiecab2000

    reggiecab2000 Rockstar 4 Years 500 Posts

    Hey guys,
    i am just curious as to getting some good aftermarket alternator brand suggestions that dont empty my wallet. I do not know my exact alternator right now although if i wasnt being lazy i could just look at it to find the amperage it is rated at, but i believe it is most likely a 105A alternator. I currently have, and have had for a few years now, approximately 1300 Watts RMS in my system plus 4 off road lights totaling 460W, i have ridiculous voltage drop when bass notes hit, although things seem to be working fine i would still like to see how much it would hurt to invest in a better alternator. possibly a 140A? just looking for anyone who knows of good/reliable brands to look at that arent ridiculously priced.
  2. Enkeiavalanche

    Enkeiavalanche Rockstar 4 Years ROTM Winner 5000 Posts

    If you have the 2 amps listed in your sig you are running about 750 RMS to your subs and about 35-40 RMS per speaker.. Get rid of the Cap unless you want to hook it up to your Lights. It will be more usefull there.. You can get a better Battery And if you want a Alt that will do the trick Ohio Gen is the only one I would go with.. Not the cheapest BUT the Best......
  3. reggiecab2000

    reggiecab2000 Rockstar 4 Years 500 Posts

    why do you say 750? are you compensating for the output at perhaps 13.4 volts? i know some people say that most amps are rated at RMS @14.4r volts, and its usually less if the voltage isnt 14.4V. which i completely understand your point then, but do you believe that much less?
    i have everything wired down to 2 ohms, so according to a "perfect" world i should have 1000 RMS for the subs and 75X4 RMS for the speakers at 2 ohms? if there is another restricting factor im not including please let me know. and of course i would rather have extra power than not enough. but i definitely dont have the funds to even spend more than 300 for an alternator...
  4. Enkeiavalanche

    Enkeiavalanche Rockstar 4 Years ROTM Winner 5000 Posts

    When I was in the Biz full time I had all the test Eqm you can think of.. And we tested Tons of amps.. If you did bring them down to 2 Ohm then at the Voltage that the GM trucks give Your M1000 is at about 850-900 and the 300 at about 45-50 RMS.. But as I said I have seen many Alt's out there. I have seen many people buy the cheaper units I have seen many of them Buy new units within 2 years.. You don't need much If you can get the GM 145 Amp one Get that it will do you fine and a good Battery..Get rid of the Bandaid (Cap)
  5. reggiecab2000

    reggiecab2000 Rockstar 4 Years 500 Posts

    well seems like you got quite the experience then!
    yes i have been looking for the gm 145A but apparently it is a pain in the arse to find online! even so with the prices im seeing for the 130A, its looking pretty expensive...and i have heard of ohio gen although it does not seem their website is working right... definitely too much money though
    I have one other alternator i have found then that i could ask your opinion about,

    DC Power
    OEM series 190A alternator
    what is your opinion of these? or suggestion of this one vs. the OEM 145A i cannot seem to find lol

    it seems that google often compares dc power and ohio gen
  6. SurrealOne

    SurrealOne Former Member ROTM Winner 1000 Posts

    I own a DC Power Engineering 240 Amp alternator (see my signature). I've had it in since September of 2011 and it's going strongly. Great customer service prior to the sale, too...
  7. sstoner911

    sstoner911 Epic Member 5+ Years 1000 Posts

    If you have $300.00 now I would set that aside and save another $200 or so and get 220 alt. DC power has some options for your truck in the $300.00 range..180 amp Alts.
  8. reggiecab2000

    reggiecab2000 Rockstar 4 Years 500 Posts

    stoner the only two for my truck in the $300.00 range are a 185A at $249 and a 190A for $269
    and thanks for the opinion surreal.
    aside from my system and lights i do plane on having my LS1 efan swap done by summers end as well, and i am not sure exactly how much amperage those fasns will use up running constantly.
    would yall say 190A max: 140A idle is sufficient or do i have to step up to the $440 price range for a 220A max: 165A idle alt.???
    thats about $140 for only 30A more..
    thanks for the insight.
  9. sstoner911

    sstoner911 Epic Member 5+ Years 1000 Posts

    If it was me, go for the 220 and be done with it. Then you won't have any regrets not doing it.

    Go big or go home as they say!
  10. SurrealOne

    SurrealOne Former Member ROTM Winner 1000 Posts

    1300 watts from stereo + 460 watts from lights = 1760 watts peak from aftermarket accessories (not including truck's electrical draw).

    Afermarket Accessory Amps = Aftermarket Accessory Watts/Volts = 1760/12 = 146.6

    Your truck can draw about 90 amps max with all OEM electrical items running, so 90+146.6 = 236.6 amps should be your rough target if you want enough amps to provide overhead for your peak draw. Realize that you will rarely hit peak, so there's some built-in overhead, already. I like having more than enough (so that I can add accessories later without having to rethink it all) so I'd meet or exceed 236.6 if it were me.

    I think this rough math places your mark in the 220 to 240 amp range. Again, if it were me I'd err on the side of more, not less. You can cut it down if you don't crank the stereo while running the lights.

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