technessjoka

is there a diagram or some tutorial online where i can make my own battery harness for an fc? or can anyone help me out with this? i cant seem to find a stock battery harness and im running out of affordable options so is it possible to make your own battery harness?

LunchboxCritter

iTrader: (9)

Yes it is possible to make your own harness. If you still have your original harness, just take it with you to a store that sells wire (parts store, audio store, etc.). Tell someone in the bay that you need to make a cable like that, they should be able to get you together.

If you don't have the original harness, then you may want to consult the FSM (factory service manual), for some guidance to where all it goes. You can find the FSM by following the link below.

http://www.rotaryheads.com/PDF/2nd_gen/

The Wildchild

iTrader: (1)

like just the + and the - terminals off the battery or all the wires that run with the + and - wire? and yea both can be done but if you want to make the whole harness your gonna need all the plugs and a lot of wire

SirCygnus

iTrader: (1)

not really. its the simplest circuit in the system.


here we go!!

4 gauge wire from battery 12v+ to starter 12v+
12 gauge from alternator post to the 12v+ on the battery.
4 gauge wire from 12v- post to ground on the strut tower, then on to the starter BODY where it it bolted with a starter bolt.

then there is a wire for the fuse box, but i dont know much about how thats routed.

also, i dont recommend using speaker wire, or going to the speaker store and getting battery terminals. they are useless.

http://rjminjectiontech.com/?p=22

that is the proper set of items to get you where you need to be and never have to worry about the wires again. remember, leave 6 inches of slack on both ends just in case.

technessjoka

thank you everybody you all have been very helpful

Akagis_white_comet

iTrader: (4)

SirCygnus, are you trying to catch the poor guy's car on fire? 12-Gauge for the Alternator output wire?? 12-gauge maxes out at 58 amps, below the s4 alternator's marginal rated output of 70 amps. Also, according to electrical guru Aaron Cake, using the starter post as a distribution point will introduce electrical noise into the circuit.

technessjoka, I'm sure that SirCygnus was trying to help, but using 12-gauge for the alternator output wire is the shortest way to catching your car on fire. Using wire that's too small will MELT the insulation right off of it, and then it'll short out against any nearby surface. The current draw from a Taurus E-fan on low will melt the insulation right off of 12-gauge. Ask me how I know.

Personally, I'd go with 4-gauge as a minimum to ensure that you have enough overhead capacity. 6-gauge would work too, but I'd go with 4 so you don't have to redo it when your alternator craps out like most FC ones do and you're looking at a FD or Taurus one. When I swapped to a FD alt on my 87 GXL, I used 5 feet of 4-gauge battery cable from Napa. And when it came time to go up to a Taurus Alternator (130 amps!), the 4-gauge is still beefy enough to handle it. I have 5 amps of headroom right now,so the alternator would have to max out (and burn out before the cable is pushed beyond the safe limit.

As for the battery being moved to the hatch now, bigger is better. What I'm using is 3-gauge THHN 90c copper building cable, rated for 158 amps

For reference on ampacity and wire size, please look here http://www.powerstream.com/Wire_Size.htm

If you're still stuck, I recommend reading Aaron Cake's how-to on battery cables. Another good article is on rotaryresurrection.com

SirCygnus

iTrader: (1)

hm... interesting. after looking at how thick that cable is, i retract my 12gauge comment. lol

dave007

iTrader: (1)

Yeah.. factory s4 alternator charging cable is 8 gauge. I upgraded mine to 4 gauge.

SirCygnus

iTrader: (1)

nice to know man. thanks. i have no tools to measure the gauge of wires. im sure my father does.

rotary#10

iTrader: (38)

Yo folks rule of thumb for electrical wire size.
Smaller size is Larger wire diameter.
Larger size the smaller the wire diameter.