OBA -> On Board Air Mega Thread & BS

The onboard air system by Kleinn for the for super duty mounts their compressors on the side and they have no problems that I have seen.

 

Yeah, i don't think intermittent use for a few tires on its side should cause a problem.

I use mine to run my SCUBA booster to fill O2 for my rebreather and bailout bottles. If tanks are really drained sometimes 30 minutes at a time.

 

Thanks for the info, I'll see what I get figured out

 

Has anyone ever combined two twin ARB compressors? I don't have much experience messing with custom air configurations but I'm looking to combine two units because my truck has 40s and my trailer has 40s (going to 42s for all six eventually). So that's 6 tires I have to fill after hitting a trail. One twin will do the job but it takes time.

 

Why not run them independently? Put one on the truck and one on the trailer and fill two tires at a time.

 

I don't always use the trailer and airing up the four 40s still takes a long time regardless with just the one twin.

 

do you have an air tank or just using the compressor?

 

Right now I have a twin with the 1-gallon tank.

 

You

Mounting both in the truck isn’t a problem as long as you can supply the current and upgrade the wiring to handle both compressors.

 

What did you secure the tank to?

 

for those routing extended harnesses from the rear, where's the best path to take up from the underbody into the engine bay that avoids getting to close to the exhaust? ARB's instructions, both written and video, are somewhat lacking in specifics

All pro has one but the vid isnt the best
https://www.youtube.com/watch?v=qttuDilhkVg

 

Don’t leave any loops that can snag or flop, stay inside of the cab mounts and as they say, follow the brake lines up and over the driver wheel well. Air is a pretty good insulator so if you maintain at minimum the same separation from the exhaust as other wires/lines you should be okay, automotive wiring is specced to withstand at least some heat. Any sections that might be exposed to debris should get split loom if it doesn’t already have it(I cover everything until it exits the undercarriage.l).

 

Just finished this for my s10

 

Thanks bagleboy, appreciate the feedback. Thought i'd post some pics showing my routing. Used some 14-2 to better show it:

From rear of compressor box, route down to frame:


Follow existing loam above the x-member near spare:


Follow existing loam driver's side of gas tank:


Keep following loam along frame:


Hug the frame and go behind first heat shield:


(different angle from previous pic):


(looking up towards master cylinder) hug the wheel well:



(looking down from engine bay) hugging the wheel well:


route under brake booster and proceed to parallel existing loam to battery:


From there, following instructions for connections (ARB-CKMTA12 / AP-308461) in this case
https://arbusa.com/arb-twin-compressor-installation/



- Connections to compressor
- Secondary switch in box
(i have no locker solenoids)

ARB Harness connections:


10-12AWG ring terminal to each power lead
6-8AWG ring terminal for both grounds QUESTION: (AP-308461) secondary switch power to +12V (switched or unswitched), do most people just go straight to battery with this one?



(pull through firewall)
Switch 1 & Switch 2 ( no lockers)
Connect isolating switch to in-cab ARB rocker switch per instructions

red/yellow to ignition/ACC power circuit, min 8 amps. Add a circuit to "IG1 10A"
blue/white to an illumination circuit.
QUESTION: What circuit to tap into here with the appropriately sized add-a-circuit? Tail?



Add-a-circuit 2-10 AMP ATM-LP


Thank you for taking the time,

 

In pic #5 does it actually go between the shield and exhaust? Next pic makes it look like it goes behind along the brake lines which is better.
Always hot vs ignition hot are the choices. I lean towards always hot but plan to run the engine anyway unless it’s a short stint.
Tail and door lock are always hot, guage and acc are ignition hot. Make sure you identify the hot side of the fuse slot and install the add-a-fuse correctly, reversed puts the fuses end to end in the circuit instead of parallel. The added circuit then gets power from the oem fuse when it should get it from the tab plugged into the buss instead. Both circuits should work with the other circuits fuse pulled. If only the oem curcuit works with only its fuse installed you have it backwards.

 

yea it does but that heat shield doesnt have the best coverage towards the frame, i'd need to route the loam further towards the passenger side and up to get it more behind the heat shield.

thanks for letting me know regarding the add-a-circuit

 

also the arb instructions call for a minimal fuse of 8 amp. is 7.5 amp still acceptable?

 

It won’t do any harm. At worst you’ll find yourself replacing it frequently so carry spares if that’s the case. The danger is using a fuse rated too high which would prevent it from blowing when it should. If 7.5A isn’t enough don’t go beyond 8-10A fuses until you know enough to know whether in your case it’s ok. You’d need to know the specs on every wire and part in that circuit and what their maximum current ratings are. Fuses are SUPPOSED to fail before anything else does. You wouldn’t put a 20 psi radiator cap on a system rated at 15 psi because it boiled over, you’d want to find out why it was boiling over. Caps and fuses serve the same purpose, they provide a recoverable failure point.

 

awesome, thank you. Also one last question. The Add-a-circuit (in this case 2-10A) says "For automotive and marine applications up to 10A and 32Vdc". Does this mean i can use 7.5A fuses in a 2-10A rated Add-a-circuit (making sure to never, ever go over 10A)?

 

Yes, it’s an upper limit rather than a minimum. In general though you want to limit their use so if you have more the a few of them it’s better to install an auxiliary fuse/relay box with its own main fuse or breaker and pull power for add on accessories from that. I have a Bussman panel in the engine bay and another fuse panel under the center console so that I limit the draw on two add-a-fuses(one always hot and one ignition hot) to less than 1A of switch current each. Power for the accessories themselves comes from one of those panels rather than from an add-a-fuse.