Modifying Napa Compressor

[psea17]

Hello my peeps! My '98 (bought new) which was totaled last yr is back. I wanted to give back to the community.

I bought a Napa compressor and modified it. After watching numerous videos, this was the design i went with:

-removed the napa hose and installed a pressure switch (1/8" npt) in it's place. this shuts down the compressor as soon as i stop inflating. Amazon.com

-drilled a 1/4" outlet in the air duct rod and tapped it using this. this doubles the air outlet's diameter. https://www.amazon.com/gp/aw/d/B01MDV3A30?psc=1&ref=ppx_pop_mob_b_asin_title

- added various 1/4" npt fittings (nipple, 90° elbow, coupler.
Amazon.com

Amazon.com

Amazon.com

-i believe you need a 5mm allen to remove the 8 bolts on the compressor caps. i removed everything from the air duct before drilling. i didnt want metal shavings in my compressor heads or air lines.

-i removed all circuitry. if it fails, i cant fix it easily. so i replaced it w a relay. the compressor draws about 90a. So a 200a relay is fine. i got a 300a. Doesnt make any difference.
https://www.amazon.com/gp/aw/d/B0859BZJNW?psc=1&ref=ppx_pop_mob_b_asin_title




-i decided on 2awg wire (cuz i had extra) for the power cable but i wouldnt go smaller than 4awg. It reduces resistance (and it's byproduct, heat). To connect the compressor's wire (approx 7awg) to the 2awg, i bought this, added ferruls to ea wire, added some solder and screwd the compression nuts down. i then used (red) sealing shrink wrap over it. There are other solutions to butt splice, but this was the most convenient and nearly the smallest option.
https://www.amazon.com/gp/aw/d/B09NJTY12W?psc=1&ref=ppx_pop_mob_b_asin_title

-90° terminal connectors on pressure switch. since i rotated the 1/8" outlet so it faces down, i used 90° connectors. something like these:
https://www.amazon.com/smseace-Insu...2lkZ2V0TmFtZT1zcF9waG9uZV9zZWFyY2hfYXRm&psc=1

-had to make 3 jumper wires (fr power switch to pressure switch, pressure switch to relay, and fr relay's big negative terminal to the smaller terminal above it (diagram below).

-i used 2 cable ties for power/ground wire support. one was 3/8" iirc and the other was 1/2". sourced at Ace Hardware. the size you choose will depend on how large of wire you use to plug your compressor into your truck's power.

-the 2 cable ties, power switch & the relay were screwed into the compressor using self tapping screws. my advice, drill the holes very small/carefully. after drilling, use a probe to see how much space you have to screw something down. You dont want to puncture anything beneath the outter shell. try to avoid getting shavings in the pump.



- all connections either used double lined heat shrink or heat shrink connectors.

-nothing extends past the compressor's base plate, nor above the two pump heads so that it packs as small as it can.

-the slightly angled (up) coupler is simply to help prevent my air hose from touching a hot pump head.

-power switch. i used the switch that came w the compressor. To mount it, i cut the mount out of the original plastic cover so i could reuse it. This worked great. I put it in a vice and used a heat gun to bend the bottom. With the foot now at 90°, i drilled a hole through it and the outter compressor housing and secured it w another self tapping screw. The screw had a washer on the top and bottom. the bottom one is just to add a little space betw the hot compressor's outter shell and the plastic switch holder.

-anderson plug. i had this on hand already. if you order one, youll need proper lugs, crimper, heat shrink, etc. the anderson is the 150a model.

-why didnt i hard wire in my engine bay?
1. heat is a compressor's worst enemy.
2. i would have either needed twice as long of an air hose (to reach my overland trailer tires) or a more complicated install running air hose to the rear bumper and mounting a coupler there.
3. i have a gx460 too. i want to be able to use the compressor w both vehicles.
4. i already had 2awg wire/150a anderson plug running fr the engine bay to the rear of the truck (so i could use my winch at the rear bumper as well as the compressor)

i think that's it! from what ive seen this easily competes w the arb twin at a fraction of the cost.

Hope this helps someone!


update. dang, i forgot this site only allows the smallest of pics. all of mine are too large. i posted the pics in an overlanding fb group, here:

https://m.facebook.com/story.php?story_fbid=9592632297514894&id=4889671181144386

 

[phattyduck]

I did a similar thing late last year (or was it summer, I don't remember?). I was able to hide everything back under the original plastic covers - relay instead of the control board, pressure switch, original power switch, etc. Female coupler as the outlet in the 'original' location with a wider opening. Original power wires, though I'm sure that hurts performance a bit.

With a 4-tire inflator, it does the tires very fast. I can get the pump out, inflator kit out, inflate the tires and put it all away in the time that my buddies take to do two tires... It actually sometimes cycles if you are just filling up one tire by itself, it pumps so fast (I used a 90-120psi switch). The 4 tire inflator kit (also built myself) is great for airing down too.

-Charlie

 

[Adamus]

Just remembered that the handle fell off mine and I need to fix it, thanks for the reminder!

 

[psea17]

i used dyneema for my handle. might go back to what came with it.


Charlie, nice job! I could have used the original plastic shell but i really want as much ventilation as possible. i go back and forth about a multi-tire inflation system. ive kind of watched others. i kind of think by the time all the hoses are stowed away, it's not much different than the old single head pump i had (air armor). but, in all fairness, almost everyone is sporting much bigger tires. im still on 265/75/16 (31.6") tires. also, space is at a premium as im considering doing the panamerican hwy.

just grabbed a 270 awning & awning rm from reign outdoors. only 2 walls (inner/outter), removable floor and i got the wind block. looked appealing because the sides and rear are squared off to the truck. nice quality fabric too. a lot to consider on a big trip like that.

 

[phattyduck]

Charlie, nice job! I could have used the original plastic shell but i really want as much ventilation as possible. i go back and forth about a multi-tire inflation system. ive kind of watched others. i kind of think by the time all the hoses are stowed away, it's not much different than the old single head pump i had (air armor). but, in all fairness, almost everyone is sporting much bigger tires. im still on 265/75/16 (31.6") tires. also, space is at a premium as im considering doing the panamerican hwy.

I'm running 265-70-17, basically the same. The valve core really becomes the main restriction with such a big pump. Even with all 4 tires inflating at the same time, the pressure at the pump outlet is 15psi+ above the tire pressure. Its more like 40psi higher with just one. I suppose if you have the valve core remover style of filler, it would work pretty well a single tire at a time and save space.

Something like this:

-Charlie

 

[psea17]

hadnt seen those before. interesting. thx

is your air line 3/8" or 1/4"? wondering if going to 3/8" makes any difference given the port is only 1/4".