Big 3 upgrade questions

[Chewy1576]

Hey all,

My battery cables are shot and need to be replaced. At some point, the wires had been ripped out of the positive cable terminal and hacked back together, and the negative cable is loose on the terminal. I can watch the volt meter on the dash tick with blinkers so there is obviously something wrong with the wiring.

Does anyone that has done the upgrade remember what lengths and gauges they used for the Positive -> Alternator, Positive -> Starter, Positive -> Distribution, Negative -> Intake cables? Also, instead of running the second Negative wire to the fender, how about running it down to the bolt on the frame where the ground strap from the block attaches?

 

[michael hurd]

Can't help you on the lengths or gauges, but on your question about the second negative wire that originally went to the fender, this will form the ground return path for the horn, headlamps, markers and turn signals on the front end.

Attaching it to the motor will work, provided there is a cable from the battery to that spot on the engine, and the cable terminals are touching, so as to have low resistance.

The alternator should get it's own, dedicated ground return path to the battery.

When the signals, high beams and horns are activated at the same time,

8.3w x 4 low power filaments in 2357 signals
28.2w x 4 high power filaments in 2357 signals
65w x 2 for high beams, add in another 110 watts if you have the 4 hi mod.
~60 w x 2 for each horn.

Granted, the high filaments in the signals are only momentary, and without the corner markers bulbs in the equation, this would be momentary pulses of up to 506w, or about 36.14 amps at 14.0 volts ( idle, alternator charging without too many other loads dropping the voltage down )

With factory wiring to the headlamps, you would be hard pressed to achieve more than 12.1V tops.

Keep in mind that factory wiring has a cross linked jacket and is rated for at least 105C temperature, and chemical resistance. Cheap PVC jacketed wire from a parts store is not as durable, and the insulation can melt with high temperatures.

SAE wire sizes ( as used on an automobile ) are anywhere from 5-12% smaller than true AWG sizes.

Ampacity of wire is based on many things, the number of wires in a raceway ( or conduit / convoluted tubing in this case ) and the ambient temperature. When the number of wires increases, wire ampacity drops. When the temperature ( engine compartment gets pretty hot ) rises, ampacity drops.

The length of wire and return path length should be used in calculating voltage drop. There are various calculators online for this.


Beware of parts unknown!!

 

[Chewy1576]

Maybe it would benefit me to keep the negative -> fender wire instead of creating a negative -> frame instead. I want to do the 4 hi mod in the future so it could also benefit to make it a slightly bigger wire. I don't have the truck at home or I would go out and measure them. I will just need to do it when I get it here.


Sent from my iPhone using Tapatalk

 

[largewon62]

My battery to starter cable was in good shape. I ran a piece of welding cable directly to the back of the alt and left the oem negative cable in place. I ran a piece of welding cable from the battery to the block and attached it to the passenger side where the mechanical fuel pumps used to mount, I then ran a piece of cable from there to the frame. I have not had any issues since I did that........I know, all I had was red shrink wrap.

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[mr98z71]

Wtf are you using red for your negative and positive? you will confuse the F$#K out of the next person who hooks it up!

 

[largewon62]

Wtf are you using red for your negative and positive? you will confuse the F$#K out of the next person who hooks it up!

Hey, it was all I had and no one else works on my truck or vehicles. I also have two Buick Grand Nationals that I do not trust to anyone else either.

I would be more than happy to change it out if you would like to send me some.

 

[Bob L]

Anyone that hooks up a jumper cable by just looking at the color doesn't belong under the hood.