OBA -> On Board Air Mega Thread & BS

Just picked up a

$91 Viair 88p Portable Compressor Kit (12V, 120 Psi, Forup to 33" Tires)

Viair 88p. Got to test it out last weekend and was surprised how quickly it pumped the 32" tires up from 20 to 32psi. Now I'm looking for a place to mount it. Would prefer under the drivers seat with a quick connect on a bracket at the side. Not sure if there's enough headroom under there yet.

 

You only have 1 tank versus 2, and no mounting hardware. 6” PVC pipe and fitting are exponentially more than 4”, but it’s super thick and will last a lifetime. I think it’s rated for almost 200 psi.

 

Well I discovered something what with the recent cold snap. My ARB compressor won't run. After I've been driving for a while and the engine bay heats up, it will run (sometimes) and often kicks off before the air tank reaches full pressure.

 

That sucks. The Aussies probably didn't think to test down to -10! Just kidding. Hopefully it's just some loose wiring and nothing serious.

 

Could be froze up. Air has lots of moisture in it, I'd bet there's some in the compressor piston head or a line/valve is froze up.

 

No, I think it might be an overload switch or something built in to the compressor's circuitry.

 

The only overload protection is a fuse, nothing resetable like a circuit breaker. There might be an over temp safety switch, I don't recall.

 

Whatever. Maybe there is ice in the air line and the compressor THINKS it is a full pressure so it shuts off. In any event, I'm keeping the compressor switch turned off while it is cold.

 

A water trap and antifreeze are a VERY good investment for an air system

 

Considering the highs have been in the low 20s and I’m working outdoors, my install is going to wait.

Someone mentioned antifreeze, where does that go?

 

I'm seeing a lot of guys running tanks in this thread- I have a VAIR 440P. Am I able to JUST have that and run wire from the battery back to wherever I'm mounting it... of course wire a switch in the cab to turn it on/off when I need to air back up?

 

Yes. A tank is nice to have if you need to maintain a constant air pressure or need high volume quickly but isn't necessary to air up. Use wire rated for the current, awg 10 for 30A and you probably need a relay so the switch doesn't supply the full current.

 

quick question for those of you with ARB dual compressors: was there anything special (wiring or other) what you had to do to get the pressure switch to work? fresh out of the box install the unit works great and fills my tank, much much faster then my old viair, but it will not shut off when it hits 150 psi. i have to cut power using the toggle. If i fill my tank (5gal) above the stated 135 psi mark and turn the toggle off then back on it continues to fill. Power pulled from the battery, grounded to the truck, OTRATTW toggle.
I'm thinking my pressure switch is defective.
I've already emailed ARB but just curious if I'm missing something.

 

The pressure switch needs to be in the same circuit as the toggle so that both must be "on" for the compressor to run.

 

In the tank.

https://www.bagriders.com/media/bag...nd_relay_wiring/viair_single_relay_wiring.pdf

 

Keyed power source is your in cab switch.

 

First off thanks for the replys
I understand how the pressure switch and relay activate and relate to one another. I was under the impression the dual had the PS on board and was ready to go out the box

 

It is on board and shuts down around the 150 mark. It is built in, not sure what the tolerance is but mine shuts off around 153.

 

Which is the impression I was under and why I'm thinking my PS is bad. Supposed to be 135-150

 

How high have you let it go? I would check it to 160 if you haven’t already. I know there are calibration issues in my tools as well as tolerance built in the PS as well. This is why I recommend up to 160 before declaring it is bad, but I’m sure ARB can answer all your questions.