my OBA diagram - will it work?

[EricsXJ]

I bought that Viair 400C compressor I was talking about but it didn't come with any wiring instructions at all. So I've looked at all the OBA diagrams I could find online (since I'm not a master electrician or engineer...) but couldn't find one that matched my plans exactly. I don't plan on using a tank, because that will work against me when I use it for filling tires. The OBA will be used for just that - tires and ARB lockers. So, do you see anything wrong with this system?

I'm going to mount the compressor in the rear of the XJ in that cubby hole across from where the spare tire was. I'll have to cut out some of the plastic to get it to fit in there.

I'm planning to have a hose quick connect at each corner of the XJ just under the tail lights. Thats a convenient spot on my rig and I think it will be well protected.

The on/off switch, I plan on getting a factory aux switch that goes right next to the rear wiper and rear defrost switches on my 2000 (I think this is where the factory fog light switch usually is, but I don't have that.)

 

[vintagespeed]

That'll work fine. On my York install I wired the relay the same and mounted the pressure switch ON the air manifold, the other thing you may want to add is an unloader valve ahead of the air manifold and after the compressor. The unloader vents the pressure in the line between the compressor & manifold, this way the compressor isn't having to start up under a load. A filter wouldn't hurt either.

On my setup the pressure switch is 110 ~ 145 psi and I've got a 3.5 ga tank for the ARB & filling tires. The tank fits well on the driver's side cargo wall.

Also, rather than putting your air chucks where they may be submerged or plugged with mud in the deep stuff, consider putting them where you will always be able to get to them. I put one in the gas door next to the gas cap & the other through the front grill on the passenger side (it's protected by the bumper/winch/jack). I will add one later on inside just to be sure.

 

[EricsXJ]

Hey thanks for the advice.

I was planning on putting the pressure swich directly on the manifold but it was hard to show that in the diagram.

As for this "unloader valve" you speak of, at the end of the leader hose that came with the compressor there is a built in "check valve". I'm guessing this is the same thing? If not let me know...

Good call on the air chuck location... I hadn't considered deep water 'n stuff. I was mainly looking for the best protection against rocks and splashing mud that is still easy to get to. I like your idea of inside the gas door - thats sweet! If I don't do that, maybe I can find a little rubber cap that can be on when not in use.

 

[Lincoln]

You don't need the unloader valve. Really Vintage didn't need one either, A/C pumps start up with much more than 145 psi anyway.

Check out a street rod magazine or Truckin magazine for the pressure switch. They have small one's that are only about 1" in diameter and 1" long.
http://www.airliftcompany.com/easystreet/PressureSwitches.htm

Don't forget a pressure reg for the ARB's. 105 is too much for them. Here is the one I used:
http://www.northerntool.com/webapp/...OS=on&TEST=Y&productId=39635&categoryId=90146

Lincoln

 

[MrShoeBoy]

Has anybody modified the ARB wireing harness to work a York compressor or a different electric compressor?

Would that be easier/cheaper than making your own?

AARON

 

[ScottRoz]

Eric, why are you adding a pressure switch?
Without a tank, what are you pressurizing that will ever get to a pressure level?
Also, I'd think a small tank would help run your ARBs without having to cycle the compressor all of the time.

 

[EricsXJ]

At first I was sure I didn't need a small tank, but then I realized that even the ARB compressor has a small tank attached to it, so now I'm not sure if I need one or not. Correct me if I'm wrong, my thinking was that the "system" needs to be pressurized to 85 - 105 psi (which is what the ARBs require). Without a pressure switch the compressor would keep running and pressure would build higher than 105 psi. Is that why one of you recommended the regulator? So even without a tank, I still have a system that can be pressurized which would be all the hoses. Its not much volume so it would probably only take a second to pressurize. Is this the wrong way to do it or should I go with a small tank?

 

[TC]

I didn't see a pressure relief valve in your drawing, I'd use a 125psi valve on the system you have. You should have a tank,otherwise the compressor will be coming on constantly. On York compressors I always install a check valve on the outlet side to prevent the system from bleeding back down. Is the Viair a York style? I'm not a big fan of hoses in the passenger compartment, be careful if you run them inside. TC

 

[Lincoln]

The viair is an electric compressor. I haven't seen a smaller electric that wouldn't puke before it got to a dangerous level. I believe the pressure relief valve is unneeded and have never ran one in the 14 years of running these types of compressors. York's are little bit different story, I've seen them push pressures in the low 200's.

Erik, I would recommend a small tank. Even a .5 gal would work. Firestone used to use a tank for the air bag overloads that was 4" diameter and about 6" long. I've also seen them used for smaller air horns.

I use an old truck oil filter canaster. It's 5" in diameter, about 14" long and stainless steel. It fits perfect under the radiator on the cross member.

 

[vintagespeed]

Has anybody modified the ARB wireing harness to work a York compressor or a different electric compressor?

Would that be easier/cheaper than making your own?

AARON

You dont have to modify anything to run an ARB off an existing OBA setup. My ARB has a dedicated airline off the air manifold and a mini regulator/gauge combo., then the ARB solenoid.

If you order your ARB without the cheesy pump they come with you get the solenoid & switch with it.

 

[vintagespeed]

I didn't see a pressure relief valve in your drawing, I'd use a 125psi valve on the system you have. You should have a tank,otherwise the compressor will be coming on constantly. On York compressors I always install a check valve on the outlet side to prevent the system from bleeding back down. Is the Viair a York style? I'm not a big fan of hoses in the passenger compartment, be careful if you run them inside. TC

I used 3/8 DOT airline & fittings throughout. The stuff is super stout, it's what we used to use on our street cars for airbags. As for running it inside, it's no biggie at the pressures we're talking about. I like DOT line cause it's cheap, easy to fix if you break a line and you just slip it into the fittings, sweet.

 

[EricsXJ]

Erik, I would recommend a small tank. Even a .5 gal would work. Firestone used to use a tank for the air bag overloads that was 4" diameter and about 6" long. I've also seen them used for smaller air horns.

I found one place that sells these http://www.truckspring.com/airsprings/firestone/product/tanks.asp 1/4 gal tank #9166, 2 port 1/4" NPT inlets, 150 max pressure, 4" diameter 6.2" long

That is small enough that it would be easy to fit and I don't think it would work against me when filling tires like a big tank would. I can see the benefits that the compressor wouldn't cycle on with the air lockers so much. A friend has Quick Air 2 and apparently there is even a small built in tank on that. I think I'll get it.

 

[vintagespeed]

I found one place that sells these http://www.truckspring.com/airsprings/firestone/product/tanks.asp 1/4 gal tank #9166, 2 port 1/4" NPT inlets, 150 max pressure, 4" diameter 6.2" long

That is small enough that it would be easy to fit and I don't think it would work against me when filling tires like a big tank would. I can see the benefits that the compressor wouldn't cycle on with the air lockers so much. A friend has Quick Air 2 and apparently there is even a small built in tank on that. I think I'll get it.

A tank will only help your system if your pump puts out more flow than you're using at the moment. Otherwise you drain the tank & are just pulling off the compressor anyway. Filling tires is a good example. Even with a 10" stroke York, I run my tank down filling a tire so the extra capacity isn't doing me any good for that (they are 38s). It DOES however help when using air tools or filling an air matress.

 

[Lincoln]

Without a small tank of some kind the compressor probably turn on every time the lockers are engaged. Depending on how much volume is in the lines it might drop below the 70 or so psi to engage the locker and then have to come back up. That's why I recommended the tank.

You are right that the tanks are useless when filling tires. A lot of my friends run 5 and 10 gallon tanks for a quick dump to seat beads. They are also running 1/2" hoses so it doesn't last long. Even a 3 gallon tank epties quick and provides no benefit.

I think the 1/4 gal. tank would be perfect for running ARB's. It should also fit in the same place I have mine so you don't have to use up anymore room inside.