So I changed my alt to a 145 amp unit I got from car-part.com. Im also getting rid of the Optima battery since they havent held a charge (I have to jump start my truck ALL the time) since a few weeks after I got them. Im putting in a new battery as well. The alt to reb box wire is only 8 gauge and the wire from the neg battery post to ground is pretty small as well. They suggest (Big 3) upgrading these as well as a wire that goes from the chassis ground to the alt mounting bolt. How many have done this?? Is it worth it? I dont have a crazy sound system, just MB quartz components, 2 JL audio 12W3 and 2 MA audio amps. I also have HID (which are supposed to use less power), Electric fans, and thats about it. Is it worth it?? What size wire and fuses, etc??

 

So no one has done the Big 3 upgrade? I went and got some 4 gauge wire and connectors. Also got gold plated top mount battery terminals. Probably going to take a shot at doing this next weekend. Anyone have any tips or pics? Ive seen the post about it, but it looked like it was on a Civic and most of the wires were pretty easy to get to for them.

 

The wire from the alt is actually a fusible link. It has thicker insulation and smaller wire. It acts as a fuse incase the alt fries out. I asked a gm parts person if its the same on both the 105 and 145 and they said yes. If you decide to upgrade the wire to the red box you will need to install a mega fuse as close as possible to the alt. They come in increments of 25 so probably a 175 would give you a pretty good protection for 145 alternator. Wire gauge should probably be 4 gauge. That should be fine or you could go bigger( smaller number). If you do that, then you need to make sure that the cable from the red box to the battery is the same gauge. Our ground wires should also be the same size from the neg to engine block. A ground from the alt to where you bolt the neg to the block couldn't hurt. All this will make your electrical system work easier.
If you decide to do it, try using welding cable because of ease of routing, and price. It can be found for under a $1 a foot in 4 gauge. Also use good quality lugs.

 

I didnt know that Thank you! Im glad I didnt jump into it. I got 4 gauge wire and good connectors, but had no idea that I would need to run a fuse there. I'll take some time and look over everything before I tackle it. I only bought 10ft of insulated cable and it was $20. Have you done this upgrade? If so do you have pics? It looks like I would have to do alot of cutting and crimping in awkward positions to get everything setup correctly. So are you saying that I should run 4 gauge wire from the neg to the block and then another 4 gauge from the same bolt on the block to a bolt on the alt?? There is only one place on the actual alt to attach a wire and that goes to the red box. Would I notice any benefit from this or is this just a "its better" mod??

 

The fuse is just a precaution. If some reason the alt spikes out, Its alot better to take out a $4 fuse than the vehicle.
I havent done this mod yet. I am currently adding a second battery using 2 and 4 gauge, and will upgrade the stock charging system after that. My dual battery has gotten a little more expensive than I initially hoped, but I will never have to go back and redo anything. Try to either use your exisiting cable for lenght atleast.
I really wouldn't worry about a ground cable from the alt. Its a steel motor, and aluminum brackets all conduct very well. This is your choice. I would just redo the factory cables in a heavier gauge cable.
I have heard that upgrading the charging and starting cables and ground cables have helped. It will make the electrical system work better. You are using and charging more current than what the system was designed for.
I have read some web pages on other truck sites that people have done this on older body styles, but have yet to see one on the nbs. My biggest suggestion is plan this out. It has taken me almost 3 months of planning and getting everything together. I found everthing online, and it ended up being cheaper overall, plus available. Ebay is my friend now.
Good luck.

 

By not doing the chassis ground though, people experience the dreaded alt. whine in the speakers (I know it can be caused from other things [like running RCAs along power wire, or poor amp ground] but typically it has been solved here).

I have done wire (0 gauge) and battery upgrades (yellow top) ...haven't done the alt, but at night I can't turn it up all the way (most likely I'll just add a second yellow top and have it next to the amps in cab).

 

Thank you very much! I thought that wire was a fusible link, and have asked around here quite a few times, but nobody has ever responded. I've heard of people doing the "big 3" upgrade and not fusing that wire...that's just asking for trouble...