The original alternator on the vehicle has gone bad and want to replace it with maybe a 200amp alternator. Are there any other electrical upgrade that need to be done to do so? Open to suggestions as well. Thanks

 

The factory alternator wiring will not handle that amount of current. I would change everything from the battery to the alternator. That includes the ground path.

 

Why do you need a 200A?

The stock 130A 3G work very well and is robust as can be.

Agreed, the stock 6awg wiring will not take it. Iraggi (sp?) make some killer alts, price is to be as expected. You are talking an easy $500 by the time you are finished with this project.

 

I'm with these guys above, on a far-from-modern truck, the 130a alternator seems like it would be something I'd use to upgrade to for that era vehicle. Anything bigger was for an ambulance or RV application, and even then, the alternator barely ran the truck and spent more time powering the application.

 

I use a 130a, stock pulley, in my 96, runs the snow plow, keeps the battery (AGM) up. Stock size wiring. No complaints.

Curious what you are using to draw that much?

 

The stock 3g alternators all come with a threaded hole on the rear of the alternator, it uses the same threads as the ear which is threaded (on the 4.9l at least), the v8 bolt down in the opposite plane IIRC so not sure about those. I found a simple metric bolt to attach a lugged cable (a stud would be better but either way), to crreate a dedicated ground. I have seen a google search result say "5/16 thread" but its metric. I have no idea if 5/16 is just close enough or if its wrong, but bring an assortment of decently sized metric fine thread bolts to the case and youll find one that works. I used an old GM sidepost battery cable, which was overkill in gauge. I just ground the end down that goes on the side post and put it on my marine post battery terminal which has a stud. Alternatively, upgrading the stud on thefender could be a fine place for this if you have a sufficient cable to your alternator negative to handle that. This is a great upgrade of the engine ground, the engine ground is pretty bad on these trucks. The alternator ground path is normally the case to the bracket (which corrodes on both sides, insulating electrically), bracket to engine block, which corrodes on on side more than the other, then engine block to starter for the I6, probably the same for V8? Which an aluminum case starter would again have corrosion potential, to a small diameter , long cable. The cable is interupted on the frame where it straps to the frame to provide a frame ground, which exposes the cable to elements and rusting and the copper to corrode, then to the battery.


heres a picture with my ground wire (large black one) running to the back of the alternator.

The thread size, i think, is m8 something, I dont remember its pitch if it was 1.25 or 1.00. I think its fine, but I could be wrong. But if that narrows it for anyone and someone finds out.. let us know.