The Big 3 on 84 GMC

[Floyd341]

Gotta question about doing the big 3. The cable from battery to my Alternator is just going to the Alnernator Bracket, it isn't going to the Alternator? Then Ground to Frame, and then Ground to Engine Block? It has me stumped because it's an older truck, and there isn't a cable going to the Alternator, just the bracket. What do I do?

[RooTxBeeR]

Follow the other wires off of the alt and see where they end up.

Edit: That one off the battery tot he alt bracket, is connected to ground right?

[Miguels]

for ground?

for ground not many have that run to it you have to add it.. if you mean power yes it has one but it like 8 gauge or smaller.. if you havent upgraded the alternator the big 3 wont help.. i think those came with a 65a maybe 85a alternator..

[rockFord_Expedition]

Gotta question about doing the big 3. The cable from battery to my Alternator is just going to the Alnernator Bracket, it isn't going to the Alternator? Then Ground to Frame, and then Ground to Engine Block? It has me stumped because it's an older truck, and there isn't a cable going to the Alternator, just the bracket. What do I do?

You have to have a charge lead coming off of your alternator.

So for aftermarket electrical stuff this is how you want to do big 3. Pay close attention.

• Add to existing charge lead from alt + to batt +
• Battery neg to frame. As short of a run as you can manage.
• And alt case to frame.

The last one is where alot of people fuck up. The idea is to allow for the most efficient flow of electrons to and from the alternator. So an engine ground isnt the most efficient way to do it although in a few circumstances a ground to the alt case is a PITA. Kepp all of your grounds (including amp grounds etc) on the same side of the vehicle.

[RooTxBeeR]

for ground?

for ground not many have that run to it you have to add it.. if you mean power yes it has one but it like 8 gauge or smaller.. if you havent upgraded the alternator the big 3 wont help.. i think those came with a 65a maybe 85a alternator..

Big 3 will always help regardless if it's a stock alt or not. As long as you are not exceeding what the alt can put out. I had a stock 60a alt in my civic, but all I had was a mbquart 500 watt amp, which I bet probably only put out less than 400 watts. So when I did big 3, was a huge change is idle and charging voltage.

[rockFord_Expedition]

for ground?

for ground not many have that run to it you have to add it.. if you mean power yes it has one but it like 8 gauge or smaller.. if you havent upgraded the alternator the big 3 wont help.. i think those came with a 65a maybe 85a alternator..

Doing the big 3 might not help achieve higher voltage etc. but it can certainly take some stress off of the alternator.

OP, the idea of the big 3 isn't to make your alternator more powerful, its to bring out the maximum potential of what you have.

[Floyd341]

So, Alternator pos to Battery pos

Alternator bracket to frame

Battery neg to frame

Is this the correct order?

[RooTxBeeR]

So, Alternator pos to Battery pos

Alternator bracket to frame

Battery neg to frame

Is this the correct order?

Yup.

[rockFord_Expedition]

So, Alternator pos to Battery pos

Alternator bracket to frame

Battery neg to frame

Is this the correct order?

The order that you do them in doesn't matter. Youre going to do it all in one shot anyways. And that's the bare minimum I would do. I usually do an engine to frame and frame to firewall (to help oem components in the dash) in addition to that.

Also, remember you are adding to the stock wiring, not replacing it.

[Floyd341]

What do you mean not replacing it? Current wires are I think 8 gauge. I want to go to 4 gauge. Also, my work uses the copper hammer on style terminals, will that be sufficient for the upgrade, and heat shrink the ends.