JKU onboard air
 

Shortly before Christmas 2017 4WD had a sale on Smittybilt 5.65 cfm compressors. I bought 2 for $152.
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These compressors only have an on/off switch and a 150psi blow off valve. Not friendly for an onboard air system. I removed the blow off valve and replaced it with a brass 1/4npt 2” nipple, a “t”, and a 120psi Viair pressure switch. I put a new 150psi blow off valve in the other leg of the “t”.
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.Removing the switch end of the compressor reveals the wiring for the switch and the circuit breaker. There is a 60A relay between the switch and the compressor motor. I cut the wire from the relay and spliced in the leads from the pressure switch. Now the compressor will shut off at 120psi and restart at 90psi

Next I mounted the compressors, one on each fender well.

https://cimg2.ibsrv.net/gimg/www.jk-...e07c37c028.jpg
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I removed the base plates from the compressors. 5/16” grade 5 bolts were used with some of the rubber from the original vibration mount. 2” bolt were used on one end and 4” bolts on the other end. On the long bolts I cut 3/8 iron pipe to the required length to let the compressors set level.
I wanted to operate the system from my S Pod
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I ran #16 wire from the S Pod relay to the battery side of the engine compartment. It was hard to find a place for the relays. I settled on a small place by the air cleaner
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I removed the air intake to allow access to mount the 2 80A relays. After mounting, the wires from the S Pod were attached. Then it was on to running the power to the compressors. I used #8 wire to the compressors. I cut off the alligator clips and used heat shrink butt splice connectors and marine adhesive lined shrink tubing. I removed the passenger rear seat belt and used ring end connectors and shrink tubing for both grounds. I used a Dremel tool with a wire wheel to remove paint for a good connection.
https://cimg1.ibsrv.net/gimg/www.jk-...9a8f136eda.jpgThe 2 power wires were ran along the inside of the jeep under the kick panels and through the firewall using a grommet under the glove box. 2 Maxi fuses (40A) were installed for the final connection.
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The air tank is mounted to the factory bar behind the rear set.
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The bar is 1 ½ x 3 square tube. Square u bolts secure a 2.5 gal Viair tank to the overhead. The dome light housing needed a bit of trimming as did the Styrofoam padding material. A ¼ npt 45, check valve, and ¼ npt x 3/8 push lock air fitting were installed. A small slit in the padding cover at each end allowed 3/8 push lock air hose to connect each compressor to the tank. I added a pressure gauge, tank drain, air chuck, and another 150psi blow off.



The 2 compressors in tandem pressurize the 2.5gal tank from 0 to 120 psi in less than a minute.

Nice write up! All said and done how much you think you have in the system? Given the location of the compressors, do you still have plenty of access to reach that hard top bolt right being the rear door, or do you not remove the hard top much? Looks like close quarters in the pictures. The lines run from the compressors to the tank are hidden under the rollbar cover?

thats a great deal on those compressors, i did the same thing with the pressure switch and mounted it in the rear of the JK. The only issue i have is i've gone through 2 of those compressors in the last few years. The last one lasted just over a year. I switched to an ARB so lets see how long that last. Funny thing is the compressors are only my back up as i mostly use CO2 so they don't get a whole bunch of time on them.

As to how much invested into the system? $150 for the compressors. $75 for the tank. Maybe another $100 for the rest. So I would say $350 tops on the whole thing.
I haven't looked at the hardtop bolt yet. I am 70+ so I'm not going to be doing a lot of hardtop removal. The wife is pretty much set on heating and air conditioning without the dust.
Yes. The 3/8" plastic pushlock .air tubing is hidden by the roll bar cover. I unzipped the cover on the vertical section to figure out where to run the tubing. I just made a slit with a razor knife at each end and slid the tubing in, and then zipped it up.
The compressors sure fill the tank fast. I will have to time it on my 37's.

innovative spot for the air tank, i like it!

on did you see any evidence of a thermal cut-off in the internal wiring when you had those Smittybilts apart?

There is a thermal breaker with reset button next to the on/off switch. The wiring has been updated recently. A 60 amp relay is now used as a switch circuit. Previously full current went through the switch.