Electrical Upgrade? Just do it!

PlayingWithTBI said:

Thanks, it was a fun project. Makes me want to do the big 3 and 4 hi mods next but I have to get back to building the cabinets for our dining room. I did this while waiting for the stain to dry before applying the lacquer on the face frames and drawer fronts.

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Big 3 is definitely worth it. I noticed a huge difference in my 97's general "performance" after doing it, especially since the original owner didn't do much in terms of keeping it from rusting,so all my ground points were crusty,after cleaning em up and running new cables & a new positive feed line for the underhood box my lights & gauges were noticibly brighter,I also feel it smoothed my idle out,not 100% on that one though,might be placebo. My radio had way less interference/noise though for sure.

I had a little time to kill so I finalized (I hope) the schematic of it "as built". At least until I change my mind

I thought I'd update this thread with my version of the "Big 3". Since the battery terminals i bought have 1 - 2GA, 1 - 4GA, and 2 - 8GA, I used those size wires for my project.

On the Positive side, I have 2 - 8GA going to the 100AMP fuse (instead of that wimpy fusible link) and 4GA feeding the distribution block on the firewall. The 4GA wire is feeding my fuse/relay block, and the 2GA feeding the Starter.

On the negative side, I have an 8GA feeding the negative terminal strip on my fuse/relay block, another 8GA feeding the fender, and a 2GA going to the front of the engine block. All the other grounds are staying the same. I haven't done the "4 high" yet. and may need to rethink it since I ordered an A/C condenser pusher fan where I'll probably need another relay for that.

I did this while I was waiting on parts for my "383" install.



Even with the old style starter and 10.3:1 compression, it cranks over faster than the previous low compression 350

Condenser Pusher Fan Installed
I wasn't happy with my cooling when stopped at a light or elsewhere. I have the 11 blade fan and a severe duty clutch on it already, which helps keeping the engine cool but not the A/C. When stopped at idle, the coolant temp doesn't get hot enough to have the clutch fully engage so, I get low air flow through the condenser until the engine temp gets up to ~205° with a 180° T-Stat.

I already had the Compressor wired up with a relay for full battery voltage when my clutch seemed to be slipping due to low voltage (~11.3V). Now I have over 14 Volts to its coil. All I had to do was add another relay for the fan using the same 15A fuse I have feeding the Compressor Coil. My EBL Flash-II has the capability of turning a fan on/off based on MPH. FWIU you'll get best air flow at ~45 MPH so, I will set the fan at 45 MPH and go from there. There's no sense in powering it up when it's not needed, it'll simply freewheel.

Here's the fan, it's a Dorman 621-300 for a newer Suburban made in Thailand - gotta be good, huh It turned out, my Core Support was already drilled for mounting the fan. I had some "self tapping" bolts from another project that made the fit easy and painless. When I ordered the fan, I also got the (Weatherpack?) pigtail too. Then, with some 3/8" wire loom, covering the wires We ran it through an existing hole.


Next was getting the wire from the ECM over to the relay. We removed the 1/4" and went with 3/8", then ran it to my relay, tapped the hot wire going to the relay box holding the Compressor coil relay.


I decided not to use one of the relays in the box so, if I wanna add the "4 Hi" upgrade, I'll still have enough in it. So, we ran everything to the front and mounted a relay there next to the radiator. All connectors, except grounds, are hot melt insulated. Then we wrapped everything in wire looms.



It took us a total of 2-1/4 hours including pulling/installing the grille, hanging the fan, wiring everything up. The power went out when we were doing this so we used a Propane Torch instead of a heat gun - some of them got a little black in the process

Now I need to hook up my laptop and play with the on/off speed for a while. It's getting hot enough outside to tax it and see results.

I'm curious to hear your findings. My dually sucks at a standstill on a hot day and it came factory with that pusher.

Supercharged111 said:

I'm curious to hear your findings. My dually sucks at a standstill on a hot day and it came factory with that pusher.

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I'll post back in a few days. Do you have the 11 blade fan and severe duty clutch along with a parallel flow condenser?

PlayingWithTBI said:

I'll post back in a few days. Do you have the 11 blade fan and severe duty clutch along with a parallel flow condenser?

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9 blade steel fan, whatever clutch came with it, and stock condenser. It'll freeze you out once moving. I just think back to what Schurkey said about fan clutches. I'd have to measure my blades to see what clutch would be suitable for it. I don't want to end up with a clutch that the fan can't disengage.

Supercharged111 said:

I don't want to end up with a clutch that the fan can't disengage.

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I had the stock 5 blade fan, the 11 is way quieter plus, with my loud exhaust system, I can hardly tell

PlayingWithTBI said:

I had the stock 5 blade fan, the 11 is way quieter plus, with my loud exhaust system, I can hardly tell

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It's less about the noise, the engine driven fans suck a lot of power.

Supercharged111 said:

It's less about the noise, the engine driven fans suck a lot of power.

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yeah, I know, the 11 pulls a lot more air and didn't seem to suck any more power - maybe due to the design and being plastic instead of steel?