LX gets Onboard Air (1 Viewer)

[TeCKis300]

1) Yes
2) You'll need it regardless of tank. It measures the head pressure coming out of the compressor. It's both a safety and an auto-off switch. Once the pump is turned on, you don't have to manually turn it off between drawing air. Once it detects it's rated pressure, it'll turn off the pump. The pressure switch should be plumbed with a "T" on the pressure side. I have mine off the T that connects the ARB quick disconnect and 8.5" leader hose. Depending on the specific pump you got, if it draws over 20amps nominal, you might want to add a relay between the pressure switch and pump.
3) Yes
4) Yes, drill holes to meet the pattern. Tapped threads in the holes to easily bolt on. The crash bar is aluminum which is easy to drill and tap. And doesn't rust
5) Yes, popping the grill off was all that's necessary for access. There's tabs all along the edges of the grill that snap it into the bumper.

Good luck!

 

[BigMF]

Thanks!

However, I was looking for the amperage and just realized that the pump I got (400C) is only 33% duty cycle. How big a deal is that? I assume that is not ideal and should get a 100% duty cycle but wanted to double check with you guys before returning the one I just got. Argh! I don’t know how I missed that!

 

[grinchy]

Thanks!

However, I was looking for the amperage and just realized that the pump I got (400C) is only 33% duty cycle. How big a deal is that? I assume that is not ideal and should get a 100% duty cycle but wanted to double check with you guys before returning the one I just got. Argh! I don’t know how I missed that!

i guess it only matters if you can't get all four tires up from 18 to normal in that 33% of time.

 

[TeCKis300]

Thanks!

However, I was looking for the amperage and just realized that the pump I got (400C) is only 33% duty cycle. How big a deal is that? I assume that is not ideal and should get a 100% duty cycle but wanted to double check with you guys before returning the one I just got. Argh! I don’t know how I missed that!

Not a big deal and not a limiting factor for filling tires. 33% duty cycle is the rating working at 100PSI. You won't be close to those pressures when filling tires. The pause between tires is likely all the cycling it needs, if at all. If you mount the unit where I did, it'll further increase the thermal limits as there is lots of cooling airflow there.

The 400C pump does draw 28amps. The pressure switch I got is rated at 20amps nominal which is probably just short of supporting the pump directly. I'd recommend to use a relay like this in between - Amazon product ASIN B000YC7GBU

 

[BigMF]

Thanks for the ideal on the relay. I'm thinking about switching (no pun intended) things around a bit and using an inline fuse with a separate switch (posssibly with a SwitchPro or sPod or clone) inside the cabin. Does this diagram look right to you regarding the wiring if I go with a separate switch?

 

[CharlieS]

Looks about right. I hacked up my arb harness to eliminate all the extra wires and think I ended up with what you drew. I left the arb switch in the engine bay and also wired it to my switchpro. It goes against my preference to keep it simple, but allows me to turn off the compressor easily from the engine compartment in a hurry, if I need to.

 

[BigMF]

Just an angle bracket supporting the few key things underneath.

Hi @TeCKis300 , how do you have the hose and ARB QD attached to the angle bracket? Was thinking it was just something like drilling a hole through the bracket, screw the QD to a 1/4" coupling on the other side of the bracket and then the hose to the other end of the coupling like below?

 

[grinchy]

I used a bulkhead fitting to pass the air thru the angle bracket mount. It was moderately pricey, like $10. Probably what you propose would work just fine. I bought that hose/coupler kit ARB sells, but when I decided to add the small tank I sent it back. Never opened it.

 

[BigMF]

Ahhh.....something like this?
Amazon product ASIN B07D6NZLXF

 

[TeCKis300]

IIRC, I got lucky and didn't have to use separate bulkhead fitting.

The ARB hose kit comes with a T. I have my quick disconnect screwed directly into the T coupling just as you have pictured. The thickness of the angle bracket sandwiched between the quick disconnect and coupling fit perfectly while creating the necessary seal. My bracket was probably something like 3/16" in thickness.

Found this picture online - these two parts:

 

[BigMF]

Yes, I have those two parts on my desk right now as I type this. Am I correct in assuming you attached the pressure switch to the other opening of the T?

Sorry to keep bothering you. I'm a shameless copier of good/successful ideas. Why re-invent the wheel?

 

[TeCKis300]

Yup, pressure sensor on the T. No problemo. These are tech forums after all, and I've done by fair share borrowing from the great hive mind.

 

[CharlieS]

Yes, I have those two parts on my desk right now as I type this. Am I correct in assuming you attached the pressure switch to the other opening of the T?

View attachment 2299816

Sorry to keep bothering you. I'm a shameless copier of good/successful ideas. Why re-invent the wheel?

One thing about your schematic, I don't think the leads to your pressure switch are + and -. The pressure switch opens and closes a connection. On mine that is a 12v + on both sides, the "input" comes from the on/off switch, and the "output" leg runs to the relay for the compressor (to energize the relay and turn the compressor on/off).

 

[BigMF]

One thing about your schematic, I don't think the leads to your pressure switch are + and -. The pressure switch opens and closes a connection. On mine that is a 12v + on both sides, the "input" comes from the on/off switch, and the "output" leg runs to the relay for the compressor (to energize the relay and turn the compressor on/off).

Yes, you are exactly correct. In my haste to put an updated image on I neglected to think it through. It’s just habit for me to think pos/neg when thinking about working. Appreciate the correction. If I get a chance tonight I’ll correct it and edit the post so incorrect info doesn’t stay around.

 

[BigMF]

4) Yes, drill holes to meet the pattern. Tapped threads in the holes to easily bolt on. The crash bar is aluminum which is easy to drill and tap. And doesn't rust

Were you able to get all 4 holes actually mounted to the crash bar? Mine appears to be too wide to allow that. I just measured the crash bar width and the width of the holes (center to center) and it is almost exactly the same width. Probably within a millimeter or two.

 

[grinchy]

Were you able to get all 4 holes actually mounted to the crash bar? Mine appears to be too wide to allow that. I just measured the crash bar width and the width of the holes (center to center) and it is almost exactly the same width. Probably within a millimeter or two.

View attachment 2307112

That sux.

 

[CharlieS]

Fabricate a wider plate, bolt plate to aluminum bumper, bolt compressor to plate.

 

[TeCKis300]

I thought I did. Hrmm.

Not all is lost and you can take several strategies here. What @CharlieS suggests.

Or redrill the grommet positions of the pump feet to locate them inward.

 

[BigMF]

I thought I did. Hrmm.

Not all is lost and you can take several strategies here. What @CharlieS suggests.

Or redrill the grommet positions of the pump feet to locate them inward.

Already innovating like @CharlieS suggested but now thinking about your option. Would prefer to have direct connection. Fewer bolts and/or nuts to loosen on the road or rust down the road.

Thanks for the rapid responses guys!

 

[BigMF]

Well.....4 long days later, I have my compressor installed and functioning. I'm very happy with the results but was not happy about how long it took.

Breakdown:

1. Most of the time was spent trying to determine the best way to mount the compressor to the crash bar since the mounting holes on the compressor were almost exactly the same width as the crash bar itself. I tried drilling new holes in the mounting plate and then holes to match in the crash bar. Then tapping those holes to screw directly into the bar since you cannot gain access to the bar to use a nut.
   1. First attempt was a failure due to the fact that my pattern was off by about 1/8 inch. Measure twice, drill/tap once!
   2. Second attempt was even more of a failure because I broke the tap off in the hole! This was my first attempt at tapping holes so I was not aware of how easy it is to snap a tap. Now I have to replace the tap in the tap/die kit I purchased just for this project.
      
   3. Gave up on drilling and decided to go with a less elegant solution and just used some thick metal mending plates from Lowes. Bolted the compressor to the plates and bolted them to the crash bar with plates on the top and bottom.
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2. A significant amount of time was also spent on determining the best place and method for installing the switch and quick connector from ARB.
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to be continued....