ARB twin compressor (or smaller)?

I agree with splitting duty…


I have a CKMA12 mounted under hood by a bracket to the left of the brake booster (easier access than the tray). After using it one time to fill up one of my 33X12 tires and seeing how hot it and the air hose got I decided to never use it for tire duty again. It also was slow.

I carry one of these behind the drivers seat for tire duty, it durable, fast, and doesn’t get hot. Also love that it’s in a ammo can for styling and also because it keeps water a dirt out of it. https://specialopstools.com/products/air-armor-m240-12v-off-road-air-compressor
 
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I agree with splitting duty…


I have a CKMA12 mounted under hood by a bracket to the left of the brake booster (easier access than the tray). After using it one time to fill up one of my 33X12 tires and seeing how hot it and the air hose got I decided to never use it for tire duty again. It also was slow.

I carry one of these behind the drivers seat for tire duty, it durable, fast, and doesn’t get hot. Also love that it’s in a ammo can for styling and also because it keeps water a dirt out of it. https://specialopstools.com/products/air-armor-m240-12v-off-road-air-compressor

I looked at that and several things bother me. First of all they show the output as cu in instead of cu ft like everyone else uses, why? To confuse us? They are also not saying at what pressure the 3500 cu in rating applies which leads me to believe it is at zero. 3500 cu in equates to 2.02 CFM, even the ARB CKMA12 puts out 3.08 CFM at zero PSI and 2.34 CFM at 29 PSI. Next is duty cycle, the Air Armor says it can run 20 min on then 40 min off which is a 33.3% duty cycle, while the ARB CKMA12 has a 50% duty cycle. It's an attractive package and looks to be of decent quality but looking at the specs I don't see how it can be faster than the ARB CKMA12. It does look like it would be a good choice to carry in multiple vehicles though if you didn't want to spend ARB bucks.
Comparing compressors is not easy when the manufacturers are not all on the same page with their specs, and I have found the really good ones are totally open and truthful with all their specs making comparison easy while the ones that do not give you all the true specs make it appear that they are withholding those numbers intentionally so you can't compare with the others and just want you to believe their hype.
 
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I looked at that and several things bother me. First of all they show the output as cu in instead of cu ft like everyone else uses, why? To confuse us? They are also not saying at what pressure the 3500 cu in rating applies which leads me to believe it is at zero. 3500 cu in equates to 2.02 CFM, even the ARB CKMA12 puts out 3.08 CFM at zero PSI and 2.34 CFM at 29 PSI. Next is duty cycle, the Air Armor says it can run 20 min on then 40 min off which is a 33.3% duty cycle, while the ARB CKMA12 has a 50% duty cycle. It's an attractive package and looks to be of decent quality but looking at the specs I don't see how it can be faster than the ARB CKMA12. It does look like it would be a good choice to carry in multiple vehicles though if you didn't want to spend ARB bucks.
Comparing compressors is not easy when the manufacturers are not all on the same page with their specs, and I have found the really good ones are totally open and truthful with all their specs making comparison easy while the ones that do not give you all the true specs make it appear that they are withholding those numbers intentionally so you can't compare with the others and just want you to believe their hype.

I hear you, but from experience… its much faster, and runs much cooler. I think someone just screwed up on their specs page. Run a CKMA12 for 20 min and feel how hot it is and tell me it should really can be running that long on a normal basis….
 
I looked at that and several things bother me. First of all they show the output as cu in instead of cu ft like everyone else uses, why? To confuse us? They are also not saying at what pressure the 3500 cu in rating applies which leads me to believe it is at zero. 3500 cu in equates to 2.02 CFM, even the ARB CKMA12 puts out 3.08 CFM at zero PSI and 2.34 CFM at 29 PSI. Next is duty cycle, the Air Armor says it can run 20 min on then 40 min off which is a 33.3% duty cycle, while the ARB CKMA12 has a 50% duty cycle. It's an attractive package and looks to be of decent quality but looking at the specs I don't see how it can be faster than the ARB CKMA12. It does look like it would be a good choice to carry in multiple vehicles though if you didn't want to spend ARB bucks.
Comparing compressors is not easy when the manufacturers are not all on the same page with their specs, and I have found the really good ones are totally open and truthful with all their specs making comparison easy while the ones that do not give you all the true specs make it appear that they are withholding those numbers intentionally so you can't compare with the others and just want you to believe their hype.

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Is says the 20 min time is recommended but max is 40 min… no specs on the sheet as to output unfortunately. Also that little arb may be 50% duty cycle, but max I’d say to do is 5min on, 5min off.
 
Went with the dual as it was rated to fill up the pressure i need for my RV tires. 90-100psi. Single can't swing it. Mounted to ABS area, I removed the plate for the mount.
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I did the same. Removed the “ABS” tray and mounted my ARB Twin directly to the bracket…

I have my little ARB locker pump mounted right on top of the driver’s side inner fender. Basically between my horns and my wiper fluid tank…
 
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I have both, small for lockers and large for tires. When I was getting my lockers done, everyone said I was crazy to send the extra cash when I already had the dual installed. Not long after getting the new lockers the switch for my dual died on me out in JV. I was able to use my wife's compressor to air back up and had my lockers the working entire time.
Twin fits in the spot you asked about. I used a 2 hole angle bracket attached to the fire wall, attached a piece of angle to that and ran it across and secured it to the fender.
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This is exactly what I've been thinking. And I have some parts I'm waiting on to see if it'll work (fit/attach securely) — before I actually buy the compressor.

I'm a big fan of redundancy, but I'm not sure what to think about two compressors just in case one fails. Generally my questions are (1) what's the liklihood of failure, and (2) how bad will the situation be if it fails. I guess carrying a spare compressor can be done in cargo or in the engine bay. But say the compressor for the locker fails... is the idea that you just grab some Teflon tape and reroute the hoses?
 
This is exactly what I've been thinking. And I have some parts I'm waiting on to see if it'll work (fit/attach securely) — before I actually buy the compressor.

I'm a big fan of redundancy, but I'm not sure what to think about two compressors just in case one fails. Generally my questions are (1) what's the liklihood of failure, and (2) how bad will the situation be if it fails. I guess carrying a spare compressor can be done in cargo or in the engine bay. But say the compressor for the locker fails... is the idea that you just grab some Teflon tape and reroute the hoses?

yes, I carry extra hose for exactly that situation. I have the fitting on the twin ready to go. knock on wood.
 
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yes, I carry extra hose for exactly that situation. I have the fitting on the twin ready to go. knock on wood.

I like that plan. Probably the hose itself cold be stored in the engine bay, so it’s always there if you need it.
 
I have both, small for lockers and large for tires. When I was getting my lockers done, everyone said I was crazy to send the extra cash when I already had the dual installed. Not long after getting the new lockers the switch for my dual died on me out in JV. I was able to use my wife's compressor to air back up and had my lockers the working entire time.
Twin fits in the spot you asked about. I used a 2 hole angle bracket attached to the fire wall, attached a piece of angle to that and ran it across and secured it to the fender.
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Do (did) you have the break-fluid spout there? I don’t see it, but there seems to be a compressor where it would be.

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That's the fill for the clutch master cylinder. If his is an auto, it won't be there.

Ah, good catch. Thanks. I think this plan won't work for me. More drawing board work ahead...
 
I have the manual transmission as well and now I am wondering if the single ARB will fit there.
 
The single seems small enough to fit a bunch of places, including on that platform, on the wheel well...
 
The single seems small enough to fit a bunch of places, including on that platform, on the wheel well...

I won't be at my Jeep till tomorrow but the attached pdf shows the dimensions of the single at 5.7"x7.5"x3.9"
 

Attachments

Finished my ARB single today. I ran a heavy cable to a 60 amp circuit breaker that i had to fab a bracket for, I will use that for the boat winch connector on the back as well as the compressor which also has the 40 amp inline fuse, plus the circuit breaker will protect the wire from a short circuit as that 40 amp fuse ARB provides in the harness is a good long ways from the battery. I also mounted a small rocker switch under the hood on another custom made bracket. After I was finished I let one of my 31" tires down to 14 PSI, fired the ARB and timed it. After one minute the tire was up to 24 PSI and after 2 minutes it was at 34 PSI so 10 lbs per minute is better than I had hoped for and I am very pleased. I also punched out some large faucet washers for mounting and the noise level is not nearly as loud as I expected, very happy with this compressor and it will suit my needs perfectly.

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I eventually got it installed. I haven’t installed the lockers yet, so I don’t have the manifold—and have not decided where to put it.

I took seriously the suggestion that being left without a way to air up would be bad, if for some reason the compressor broke activating the lockers. (I’m not clear on how that might happen, or why it’s more likely, but I believe it’s a risk.)
Still, I don’t wheel alone, and someone else can always provide air. In the worst case, my little rechargeable compressor will (with breaks) eventually get my tires aired up enough to get me home.

I really appreciate everyone’s advice and suggestions!

Here’s a thread where I explained how I installed it. There were some unexpected issues with the tight space.
https://wranglertjforum.com/threads/arb-twin-compressor-on-the-abs-tray-in-a-manual.70669/
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I took seriously the suggestion that being left without a way to air up would be bad, if for some reason the compressor broke activating the lockers. (I’m not clear on how that might happen, or why it’s more likely, but I believe it’s a risk.)

It would be a waste regarding wear and tear to use such a large compressor for air lockers. The air lockers just need a small burst of air every now and then to lock. I wouldn't want such and expensive compressor to be left on all day just for these small needs for air. It seems like you would wear out the compressor faster doing it this way.

I suggest installing a small compressor just for the lockers. Save the twin for the end of the day when you air up.

I was running the twin on a previous Jeep, it was my only compressor. It was a hot day, and the compressor failed in the middle of a hard trail. So I didn't have lockers for the rest of the day, had to get a tug on many obstacles. Also had to borrow a compressor from someone else to air up at the end of the day.

It was still under warranty at the time and was fixed for free. Though it took them two months to get it back to me.

On my current Jeep, I'm running a small ARB for the lockers. I have a separate larger compressor (not ARB) for airing up.