Big 3 Upgrade Directions w/ Pictures

[Brandon X]

Here are the directions for upgrading your Big 3 for our OBS Tahoe's with a Vortec engine. Wire measurements are on page two. Any other questions feel free to ask.

http://i53.tinypic.com/2hdqzwo.jpg
What it will look like when finished. The wire closest to the camera is the one you will be replacing first, and the one behind that is the one you will be replacing last. The second wire is over to the right out of the picture.

1. Make sure your engine is completely cool before beginning. Identify the three cables being replaced. Make sure you can reach both ends of all cables.

2. Disconnect your battery, starting with the negative cable first then the positive cable.

3. Begin adding your new cables along side the existing ones. I will begin with the alternator positive cable.

http://i56.tinypic.com/etdrlu.jpg
You can see where the alternator positive post is.

4. Locate the output post on your alternator and remove the nut. This will be located behind it if you are looking at your alternator from the front. Slip the new cable onto the lug and replace the nut. There is no need to disturb the existing cable but I removed mine because it was a little harder to put the nut back on with it on there. Route the new cable to the battery and position it to connect to the positive battery post but do NOT connect it.

http://i52.tinypic.com/5l8cb4.jpg
This is where I have my neg to chassis ground. It should be in the same place on yours but as you can see I have an Optima Yellowtop which has side and top posts. So I used my top post to make things easier, but of course if your battery just has side posts that will work just fine.

5. Locate where the negative battery cable attaches to the chassis. Remove this bolt or screw and the OEM battery ground cable, and clean the mounting area while its off. Make sure there is no dirt, rust, paint, etc. in this location. While you have the bolt removed, we are going to move on to the next step since there will be 2 terminals you will have to have here...

6. The chassis to engine wire runs from where you just removed the bolt, to a bolt on the engine block. I used my alternator mounting bracket since it's easiest. I ran this wire beneath my CAI.

7. Connect your neg batt to chassis ground wire along with the original, and your chassis to engine (alt bracket) ground wire at the chassis side. Route this new cable back to the battery and position it to be attached, or connect it to the negative terminal but do NOT connect it to the battery yet.

http://i56.tinypic.com/208ekuf.jpg
You can see here how at the very right side of the picture how my terminal is connected to the alternator mounting bracket. That main wire you see is the wire you replaced at the beginning, the alt positive to batt positive. Don't worry about that.

8. Now back to the engine ground side of the wire you just connected. Remove the alternator bracket bolt, slip the ring terminal in and put the bolt back on and tighten.

9. Clean your battery posts if you want to (recommended) and reconnect the positive battery terminal first, then the negative one. At this time you should also check to see if all your wires are out of the way of anything that gets hot or moves. Use zip ties if necessary.

10. Now go fire it up and if you followed the directions correctly she should be running like a raped ape!

Good luck!

[brooks93]

whats this do for you. Charge the battery better? allow more amp draw from the alt?

[foreverfalcon40]

Dude! Thanks!

[Brandon X]

whats this do for you. Charge the battery better? allow more amp draw from the alt?

It allows the most current to flow through your charging system basically. If you have dimming problems, this will help you. It's really a must for all big systems.

Yw ff40, PM if you have any questions or if you need my cell for when you go to do it.

[99Yuk]

This is a good writeup, thanks!

What size wire is that? 4?

[Brandon X]

0 gauge wire.

[BlueTahoe2001]

Clean that up with some Wire Loom. Tuck all the wires and that would look sweet!

[99Yuk]

Clean that up with some Wire Loom. Tuck all the wires and that would look sweet!

What? No way! That big red wire looks good. Kinda, if your face, yup, I've done some mods look.

[foreverfalcon40]

I actually need measurements so I can cut wire off the loom at work :) I just can;t take spools of 0 guage wire home lol

[quietfly]

I actually need measurements so I can cut wire off the loom at work :) I just can;t take spools of 0 guage wire home lol

in total for the OBS its about 11 feet of wire. 12 if you want room to route and make things look closer to stock.

[Brandon X]

I'll get some measurements for you ff40.

[foreverfalcon40]

thanks

[foreverfalcon40]

Any measurements yet?

[LazyAssLou]

Great write up!

[Brandon X]

A few people have asked for measurements so here they are. You're gonna need a total of about 60 inches of wire just to be safe.

23 inches for alternator to battery positive.
7 inches for the battery negative to chassis.
30 inches for chassis to engine block.

These are all based off my directions and the measurements aren't exact, but you don't need exact. Hope this helps.

Also, I don't think im gonna be building any big 3 kits once I sell my rims. I figured you have the directions with pictures and you have the measurements, you can just buy the wire and crimp some ring terminals on the ends yourself it's not that hard. And plus I just can't sell my rims for some reason. I got em up for $800 on craigslist and nobody is interested. Might be because winter is coming, or it might be because you got people selling ugly and cheap 22's with tires for $500.

[Biggwaukegan]

You can always use better terminals on the battery. The ones hes using are just ur basic bs ones. Try and find a good set like raptor or something.

[Brandon X]

You can always use better terminals on the battery. The ones hes using are just ur basic bs ones. Try and find a good set like raptor or something.

I don't really see a need in using expensive terminals for the big 3 upgrade. Yeah it would definitely help and the ones I used are just some generic cheapies but I honestly don't see a reason to spend the money on better ones.

[Biggwaukegan]

I understand your take on it. But heres 2 reasons why to go better. Heck 3.
1. More Metal Contacting area. Cant hurt any.
2. Looks. Mine looks cool yours flat out doesnt.
3. Voltage meter built in for quick reading of volts at battery. Not a bad thing to have.


So yea they do the same thing but If you got the dough get the good ones is my vote.

http://www.raptor-online.com/product_individual.php?id=78

[steamroller]

I understand your take on it. But heres 2 reasons why to go better. Heck 3.
1. More Metal Contacting area. Cant hurt any.
2. Looks. Mine looks cool yours flat out doesnt.
3. Voltage meter built in for quick reading of volts at battery. Not a bad thing to have.


1. True
2.:rolleyes: Be sure to add that to your sig
3. Can't see it while you're driving, so the factory gauge will have to suffice

[foreverfalcon40]

I don't see the need to spend the money on a digital volts gauge at the battery. In my truck I have four, that would make number 5. I was at overkill on volts gauges at 3.

The chasis to engine, thats ground aka BLACK wire? I'm getting wire at work, so I'm going have black and red appropiately placed.

[Brandon X]

The chasis to engine, thats ground aka BLACK wire? I'm getting wire at work, so I'm going have black and red appropiately placed.

I'm not sure lol. It's either the negative to chassis wire or the chassis to engine block.

[foreverfalcon40]

So basically its a ground?

[Brandon X]

I guess so. I don't know tbh.

[Biggwaukegan]

yea its a ground

[foreverfalcon40]

yea its a ground

Thanks!

ff40

[raptorforme93]

Do you have to use 0g wire or will 4g work? I have lots of 4g but im out of 0g. Will it make that big of a difference?

[Brandon X]

4g will work. Anything bigger than the stock wiring will make a difference. However if you're running 0g on your system I recommend using 0g on the big 3.

[AtomicHoe094]

how do you crimp/solder the 0gauge to the ring terminals? whats the proper way of getting them secure?

[Brandon X]

I used a vice at my buddys shop to crimp the ring terminals. It's not really the best way to do it, but it's the easiest and gets the job done. It's better to solder the ends.

[AtomicHoe094]

i was looking at a crimper designed for 0awg and small wire. it was like 200 bucks, but if soldering is the way to go then that doesnt cost a damn thing

[Brandon X]

Yeah soldering is the way to go. I don't know how to solder or have a soldering gun so I just crimped with a vice.

[carcrz]

i was looking at a crimper designed for 0awg and small wire. it was like 200 bucks, but if soldering is the way to go then that doesnt cost a damn thing

you dont need a crimper get you a propane torch from home depot some solder
use a vise grips to hold your ring terminal and use the torch to heat up the solder and terminal ones it melts stick your wire in it and hold it till it cools down then get some shrink tubing and make it look pretty here is a pic to give you and idea

http://i920.photobucket.com/albums/ad42/carcrz/DSC04235.jpg

[raptorforme93]

I run 0g wire to the back where I have a distribution block to run my two amps. Ill just have to use the 4g that I have laying around. It is very good wire though, not the cheap stuff. And as far as ring terminals go I usually use my hammer as a crimper :) then I solder what I can. Has always worked well for me.

[sparg93]

Quietfly - I saw your post recommeding 12ft of wire vs 5ft from Brandon.

How did you route your wires? (I haven't done the upgrade yet, just wondering)

[T-Bagg]

I have a 170amp alternator. When I first start it squeals horrible until I rev it once or twice past 2500rpms. And if the everything isn't warm and I put a load on the electrical system(off-road lights, ELocker) it'll squeal at lower rpms and all the lights dim. Will the "Big 3" help that problem?

[SunlitComet]

a new tensioner and belt should cure that problem

[T-Bagg]

a new tensioner and belt should cure that problem

Have new tensioner and have tried multiple belts. Problem stays.

[Brandon X]

Bump for anyone who needs this.

[xanatost]

Awesome!! Was looking for info for this. Thanks :) This should be a sticky too

[Monstar_est87]

Yea soldering and heat shrink tube looks really clean...

[gpracer1]

I would also think about upgrading the main power cable from the battery to the fuse block (the one that runs across the radiator shroud). When the truck is running, all the power is going through this undersized wire and it is long (voltage drop). The positive to the starter is only for starting.

[sparg93]

GPracer - unless you are running accessories directly off of the fuse block or tapping into a wire off the block, what is the benefit to the larger wire?

[gpracer1]

GPracer - unless you are running accessories directly off of the fuse block or tapping into a wire off the block, what is the benefit to the larger wire?

When I have the front and rear air on high, radio on, headlights on, and I roll down the window, I could be sucking down 90 amps through that little skinny 7-8 foot wire. It cant be much bigger than 8 ga. For a wire that long carrying that much load, bigger is better, just like the alt to batt, etc.

[sparg93]

hmmm..i have some extra 4ga laying around, I'll have to try that to see if there is a difference with all my accessories on!!

[SunlitComet]

actually 6 ga for battery to the power block. 2ga from battery to alt.

[gpracer1]

actually 6 ga for battery to the power block. 2ga from battery to alt.

Do you happen to know what the factory size is for each?.....looks like 8 ga to the block and 10ga? to the alt.

[SunlitComet]

As listed above but with correction. Alt to battery is same as 6 ga to power block. A 10 ga fusible link is spliced in nearest the battery for the alt to battery. The 2 ga. was actually from battery to starter. Sorry about that. That was for '96. I think '99's went to a 4ga. from batt to power block. Can double check others if needed but I think other where similar in size. Having to convert from metric to AWG size on the diagrams. My subscriptions are far '95,'96 and '99 so I get coverage for '92 to maybe 2000 carryovers but sometimes it takes more research to find out exactly what wire was redesigned in a '98 for example. '98's should be same as say '96 but of course a new auto 4x4x was introduced that changed diagrams. So I go to the '99 charts for that. Make sense.

---------- Post added at 07:23 AM ---------- Previous post was at 07:20 AM ----------

Any 2ga. high end wire would be good for upgrade on batt alt or power block with everything else in system stock.

---------- Post added at 07:29 AM ---------- Previous post was at 07:23 AM ----------

Personally want to go high amp alt with some extra batteries but run inline fuses with a power post where POS+ from power block, alt and batt meet up. Have not been fan of the double stack battery terminals with no fuse protection for battery to power block.

[sparg93]

Any 2ga. high end wire would be good for upgrade on batt alt or power block with everything else in system stock.

Even if you don't have 2ga lying around, adding almost any extra wire between battery and fuse block is an improvement!!

Personally, I'm going to see what gauge fits in the channel on top of my fan shroud. If i can't go any larger then stock, I'll think of sending a second wire over there if I can hide it and/or make it appear stock.

[SunlitComet]

someone here had a 2 or 4ga in the slot but had to delete the convoluted tubing protection.

[creedcop]

I did the big 3 upgrade tonight and 4 guage will fit on the fan shroud and also you can reuse the factory wire loom. It actually fits better then the 6-8 guage wire that was there in the first place. Will have pics of the install probably tomorrow night or by 4th of july. I am doing a dual battery setup so it takes a little longer to get all your wiring in order and to look like stock.

[sierraman]

here is a link to creedcop's wiring upgrade we installed this weekend

http://www.tahoeyukonforum.com/forum/showthread.php?p=333578#post333578

[robhenry2990]

sticky this plz plz plz plz

[knoslf]

nice! Fortunately when I went out to look at mine I noticed the previous owner already did this mod! And theres already 0gage power ran to the cargo area as well as ground, rem, and rca's:)

[jdpber]

Damn son you freaking lucked the hell out not having to buy let alone run anything to the rear..