Electrical Questions / Wiring

Electrical and Ignition

  1. YoungDuster

    YoungDuster Well-Known Member

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    Hey im looking to run my new electrical system next month and I just want to make sure I have everything im going to need to run it properly, Im hoping to run a newer sound system in the car something like 2x110 RMS at 2ohm, 2x100 RMS at 4ohm and a 2x 10in Sub with 300 RMS each at 4ohm with a final impedance of 1ohm, I got a 4500w 5 Channel. D series Amp and the alternator upgrade im putting in will be 140amps will it be enough to run this system, I have a decent battery something like 130min 950 cold crank only 5 months old. What types of wires should I run also with the MAD electrical work around can I still use the Big Three upgrade?, as well as any tips for running the wires should I put fuses in what parts should I need?, the engine harness is being changed to one that will support an Electronic Ignition, don't know if that will affect anything. any help or questions to explain anything more are always welcome thanks guys
     
  2. 67Dart273

    67Dart273 FABO Gold Member FABO Gold Member

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    Once you have done the MAD conversion, that removes SOME of the weak stuff in the car. You have to constantly keep in mind several things..........

    These cars were REALLY under-fused compared to today, and were not "meant" for large power hungry options. Ma knew the ammeter was a problem, as she had what has become known as the "taxi / fleet" wiring which was a "MAD like" mod to relieve the bulkhead

    But that ain't all

    Other connectors and switches deteriorate, and unlike 1970, you can no longer buy solid replacement quality replacements for switches, certainly not OEM

    So be careful of stuff like your headlight and ignition switch. you can relieve the ignition switch by using it to trigger relays instead of operating loads directly. Crackedback offers a nice add-on headlight relay kit on here.

    Be careful where you tap off for your new stereo. Once you get the MAD change done, the starter relay "big stud" is a good place. As said above, if the new system needs key switched components, use a relay, fused separately

    You are going to have to expain what you mean by "Big Three" upgrade?

    If you are referring to only upgrading the ignition, with an otherwise factory underhood harness, that should not affect or be affected

    "As you get into this" I'll probably step you through to be sure the charging voltage is correct. This may or may not get into harness voltage drop issues.
     
  3. YoungDuster

    YoungDuster Well-Known Member

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    Big three is upgrading the wiring from alt to battery and engine ground and chassis ground, to something like 0 gauge, makes the charging greatly more efficient, every thing i read its something you must do if your running any large sound systems but as its easy to do and pretty cheap so i figured why not
     
  4. YoungDuster

    YoungDuster Well-Known Member

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    Here are a few pictures of what im working with if you see any issues or potential issues let me know also any info on what i have here is much appreciated
     

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  5. 67Dart273

    67Dart273 FABO Gold Member FABO Gold Member

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    This may or may not be necessary. and it may be "audio hype" which is rampant

    There might be some consideration. Do you have an understanding of A.C. circuits, impedance, and such? "In basic" here's the idea

    When you are transferring very large amounts of power (high wattage stereo) using very low load impedances (such as 4 and 8 ohm speakers) this starts to require large amounts of instantaneous current, in order to maintain the power. Also, trying to operate amplifier devices at "only" 12V makes this worse, as the devices themselves are subject to large resistance losses, known commonly as "I squared R" which is a reference to the power formula, P in watts = I (current draw in amps squared) X the resistance. This concept holds true, whether tail lights, you house system, or the huge transmission lines across country.
     
  6. YoungDuster

    YoungDuster Well-Known Member

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    Another load of pictures
     

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  7. YoungDuster

    YoungDuster Well-Known Member

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    and the last picture
     

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  8. 67Dart273

    67Dart273 FABO Gold Member FABO Gold Member

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    The photos.....big issue I see is the condition of the bulkhead. You may have problems with headlights and ignition voltage. You CAN rebuild those connectors, you can buy the terminals what are known as "Packard 56" various place. I ordered mine online from an outfit called "clips and fasteners." I believe they were Aweco (spelling?)
     
  9. BillGrissom

    BillGrissom Well-Known Member

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    It looks like your question expanded to "everything about my car". Always tell us what you have. From the photos, I infer a 1971+ A-body w/ small block, manual tranny, and drum-drum brakes.

    With all speakers at max volume (about to smoke), I add up 500W, which would be 42A. Even if you allow 50% loss in the amp, that is only 84 A, which a square-back alternator could manage. Also, you won't always be at max power, unless playing a repetitive rap bass line. Grunge music always has a slow acoustic part where the alternator would be recharging the battery for those "now the part where we play really loud" sections. I think people get carried away in thinking what alternator they need. If your battery stays charged, it is doing its job.
     
  10. YoungDuster

    YoungDuster Well-Known Member

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    ok so would it be better to run a secondary wire from the alternator to the amp itself to power it off the alt not the battery? i do have a basic knowledge of it but i have not practiced in since school 5 years ago
     
  11. YoungDuster

    YoungDuster Well-Known Member

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    Well good news i never listen to rap i just put up all the pictures i had at the moment some are from trying to get my block number an such mainly it was for how my wiring is set up the i have a full replacement for the parts that are damaged and witht he pictures id understand more when someone say see whats in picture 1542 thats where you want to run a wire through*, for example its just easier for me if you reference off something i can see since i dont know everything by name when dealing with electrical
     
  12. YoungDuster

    YoungDuster Well-Known Member

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    early 72 Duster 3 speed auto trans, 318 not sure if LA or Poly because the car is a 340 but the 340 was removed before i purchased and the man was unable to tell me the year of the block
     
  13. YoungDuster

    YoungDuster Well-Known Member

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    I have a full replacement for the bulkhead side since i didnt pull the dash apart to see if it burned any other wiring on the dash side
     
  14. BillGrissom

    BillGrissom Well-Known Member

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    The alternator output stud is already wired direct to BATT+. In the factory, it routes thru the dash ammeter. After the MAD Bypass, it will be exactly direct.

    You don't want to use BATT+ (or ALT+) directly to the amp (unless it has an on/off switch) since those are "always live" so the amp will draw down the battery overnight. You should power the amp via a relay. Actuate the relay's coil by the ACC wire (under-dash) so it turns on with the key. You can't use a standard 40A automotive relay. Maybe need a "solenoid" like the external starter one on 1960's Fords, if your amp as bad as you state. But, read the amp manual for direction.
     
  15. YoungDuster

    YoungDuster Well-Known Member

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    ok ill try and wire it with the key itself so that it starts when the car does if that proves really difficult i can was run a switch in the console
     
  16. YoungDuster

    YoungDuster Well-Known Member

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