Installed the compressors today, and like everything else, it turned into a project. The air tank only has one port on it and its on the bottom. So I welded a 1/2" bung on each end of it. I would have removed the tank to do this but I would have had to removed the fuel tank to get to the bolts so I just welded them on under the truck, not too pretty but functional.
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Once that was done I looked for a good location to mount the compressors. I wanted to install them in the bed but paperwork said to keep them away from moisture and I figured it would be a pain to protect them. Locating them under the hood is out of the question because of space so I decided to mount them in the cab. WOW space is in short supply on these trucks, you definitely need to get creative. My last rig was a full size Blazer so there was tons of room for anything I wanted.
I made up a couple mounting plates out of some scrap 3/16" plate, welded them to the rear floor channel and mounted the compressors. I figured that I'd plumb the system with PEX, it's rated for 160 psi and the press switch is set to turn of at 150 psi. so I should be well within a safe operating range. After a couple trips to the hardware store I was finally able to get the system plumbed.
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The specs say these things draw a combined 60 amps and I wanted to be sure that I didn't have another "THERMAL EVENT" so I'm using a leftover Warn winch solenoid instead of a relay to activate them. I was going to carry a spare but figured I'd just wire it in as a back up. If I ever have a failure all I have to do is move one of the jumpers in the MP-280 splice pack and it will switch to the back up solenoid. I'm using a 75 amp resettable circuit breaker feeding a 6 ga cable to the solenoids. From there a 10 ga wire is tied into the compressors so I shouldn't run into any excessive draw issues. I'm using a MIL Spec waterproof DPDT switch (eventually they will all be changed over to these) with an aircraft switch cover just to follow the theme of what was already there, plus I think they're pretty cool, and an indicator light. Not that I'll forget they are on, they are plenty loud enough in the cab to hear over just about anything. I'm pretty happy with how it turned out though, Theres plenty of clearance between the compressors and seats and I can clearly see the air gauge. The photo of the gauge was taken about 2 hours after I turned off the compressors so I clearly have a small leak I need to find.
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Now time for testing. The specs. say that it will take 1 min. 15 sec. to fill a 2.5 gal tank from 0 to 145 psi. I didn't think to time it but it certainly took longer than that to fill the tank. The other thing is that I really don't know how big the tank is, I'm just guessing at 2.5 gal. If I have time tomorrow I'll measure it as well as get an accurate fill time. I removed the valve core from one of my tires (42.5 x 13.5 x 17 Bogger) and completely drained the air. I then timed filling the tire from 0 to 15 psi. and it took exactly 2 minutes. And the compressors didn't drop below 80 psi while filling, so I was defiantly pretty happy with that. I also checked current draw while running them and found that it isn't that bad. For the most part it runs around 28 to 35 amps until about 120 psi or so. then goes up a little. It tops out at 45 amps just before shutting off at 150 psi. The thing that I didn't expect was the heat. I expected it to get hot, but wholly shit do these things heat up. The manufacturer has a caution not in the manual:
"CAUTION:
Never touch the air compressor or fittings connected to the air compressor, with bare hands during or immediately after use. The leader hose and fittings connected to leader hose will become very HOT during and after use. If necessary, wear heat resistant gloves to handle fittings, air line, and leader hose."
This is the understatement of the century, after running the compressor long enough to fill the 2.5 ??? gal tank and bring one 42.5 x 13.5 x 17 Bogger from 0 to 15 psi. the compressor head was 220 degrees and the end of the leader hose was 160 degrees. Thank god I made sure that there was a couple inches of clearance between these and the seats.