Understanding OBA

This is something of a followup to my previous thread on the subject. I'm still looking to run permanently-mounted OBA, and the main considerations are a) keeping costs low, b) running it electrically since I want to keep my A/C, and c) choosing the right compressor for the job. In the couple of days' research I've put into this, there are a few things that have crossed my mind:

1) The main use for this at present will be airing up. Running air tools is not a serious consideration at this point.

2) Duty cycle should be at or as close to 100% as possible. Stopping after filling 1.5 tires to let the compressor cool down is not something I want to deal with.

3) Durability is paramount, since it's most likely going to be mounted under the hood.

4) CFM should be as high as possible. Spending 20 minutes (or more) per tire going from 16 to 32psi is unacceptable.

5) Future plans call for a front ARB locker, and from what I've gathered they require 80-100psi for activation. Basically, this means a compressor capable of around 125psi, keeping to the CFM and duty cycle requirements above.

So far, I've looked into the Lincoln / Cadillac suspension units, Viairs of various capacities, and adapting an auto parts store special. The latter seems to be the least-appealing of the options, based on the specs I'm reading.

Viair has some nice units, but the price is higher than I really want to go. FWIW, the same applies to ARB - and on a price/performance ratio to the Viairs, the ARB compressors aren't even close.

The Cadillac unit seems to be the closest fit for what I'm looking to accomplish, but having read through this writeup the only thing I don't quite grasp is which models of Cadillac are likely to have the air compressor. I know the writer mentions mid-'80s vehicles, but which ones are likely to have it, and on what trim levels?

Any help on this will be very gratefully received... I'm on a very tight budget right now, and this is something I have zero familiarity with.

the caddilacs will take you FOREVER to refill tires...(at least that is what i came to understand when i looked into them)

PM Brad (kid4lyfe) i know he had an awesome OBA system that re-filled my tires at winterfest in a snap. Electric, tank, ran air tools to help out lbXJ - worked real well

-Ranger

XJ_ranger said:

the caddilacs will take you FOREVER to refill tires...(at least that is what i came to understand when i looked into them)

Click to expand...

Good to know. I kind of figured this might be the case; they were intended to fill suspension airbags, not tyres.

PM Brad (kid4lyfe) i know he had an awesome OBA system that re-filled my tires at winterfest in a snap. Electric, tank, ran air tools to help out lbXJ - worked real well

Click to expand...

Thanks for the pointer on that; I'll drop him a message about it. Tools aren't a priority here - honestly, I'd like to avoid a tank as it's going to eat up space somewhere. But if the compressor's up to the job on its own, I'm definitely interested.

The caddy Compressors work, if you have 1 for each tire it only takes like an hour or so.

no seriously i tried the caddy compressors for a while actually had 2 hooked up together at one point it was very slow took about 5 minutes to fill a 31x12.50 from 12-32 psi. But there readily available.

Why not use a york next to the a/c compressor? That's what i've done works great, 100% duty, i run air tools, fill air mattresses, and blow dirt out inside.
I relocated my battery the rear but if you move it to the driverside you have no problem with clearance.



You can see the York right next to the A/C compressor

Dingo

I have had luck with those high volume compressors at the local parts stores like Kragens. They are about $25 ea, the one I have filled my 31x1050 from flat to 36 psi in about 5 min. If I had the two and a tank in between like the caddy setup it would probably get a normal trail air up from 15 to 36 in under 1 min. This isn't ideal (consider the duty cycle), but $50 for a simple OBA, isn't bad. Right now I mainly use my CO2 and keep tht HV compessor for backup.

This is the compressor I'm running;
http://www.truckn-store.com/product.asp?returnURL=default.asp&ID=84617
-3/4 HP motor
-100% duty cycle
-oiler and filter
I've been using it for a year now with zero problems.

I've thought about insalling a power inverter and then plugging in a small 110 compressor. I've seen some pretty nice looking ones with a 1 gallon tank for about $80-100. Then you'd have the 110 outlet to plug in other stuff too. Has anyone tried this? Would it work?

Chad

chad said:

I've thought about insalling a power inverter and then plugging in a small 110 compressor. I've seen some pretty nice looking ones with a 1 gallon tank for about $80-100. Then you'd have the 110 outlet to plug in other stuff too. Has anyone tried this? Would it work?

Chad

Click to expand...

compressors take quite a bit of power to kick over initialy, however that is an idea that im going to look into...

kid4lyf said:

This is the compressor I'm running;
http://www.truckn-store.com/product.asp?returnURL=default.asp&ID=84617
-3/4 HP motor
-100% duty cycle
-oiler and filter
I've been using it for a year now with zero problems.

Click to expand...

Have you tried running an impact on it?

chad said:

I've thought about insalling a power inverter and then plugging in a small 110 compressor. I've seen some pretty nice looking ones with a 1 gallon tank for about $80-100. Then you'd have the 110 outlet to plug in other stuff too. Has anyone tried this? Would it work?

Chad

Click to expand...

I have consdiered that idea, but found that those small 110v compressors don't really do any better than the cheap 12V compressors. The only samll benefit is the tank.

Kejtar said:

Have you tried running an impact on it?

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Often.
Too often.
I have a small (<1 gal) tank permanently plumbed into the sytem. That's OK for running the ARB. When I go out wheeling I plug a 5 gal tank into the system. This gives me enough volume to run air tools.

kid4lyf said:

Often.
Too often.
I have a small (<1 gal) tank permanently plumbed into the sytem. That's OK for running the ARB. When I go out wheeling I plug a 5 gal tank into the system. This gives me enough volume to run air tools.

Click to expand...

Cool... primarily I'm looking at using to pull the nut of the front axle shaft to R&R it.
Btw, where did you place that tank? is it permanently mounted?

Kejtar said:

Cool... primarily I'm looking at using to pull the nut of the front axle shaft to R&R it.
Btw, where did you place that tank? is it permanently mounted?

Click to expand...

I shoehorned it behind the left cargo panel. Completely stealth. I don't have hosting so PM me your email and I'll get you pics.

I like a lot of the ideas posted... But my budget's tight on this. $50 would be a good number to keep close to.

Caddy compressors are looking less and less like the way to go just on the amount of time they take to air up. The York compressors are great, but more work than I want to undertake at this time.

What I'm looking at right now is something like this - a trip to Kragen's in the works anyway for antifreeze in a bit, so I'll do some comparison shopping while I'm there. With tools not being part of the equation, my main concern is being able to air up from 16 to 32psi in less than 5 minutes per tire.

Any comments on running a setup like this, at least until I can afford a better solution?

Second vote for the York.

I've got one. Mounted in the same location as Dingos. Used a desiel XJ battery tray to relocate the battery across the engine bay.

Plug a portable tank in when I need it.

Filling a 31x10.5 from ~8 to 30psi in roughly 35 sec (IIRC) with the tank mounted, about 2min without the tank and engine idling (would go faster with the engine reved up a bit).

I run some air tools on it no problem. Got a front 44 with ARB waiting to go in, will be using the York as a supply for it.

casm said:

I like a lot of the ideas posted... But my budget's tight on this. $50 would be a good number to keep close to.

Caddy compressors are looking less and less like the way to go just on the amount of time they take to air up. The York compressors are great, but more work than I want to undertake at this time.

What I'm looking at right now is something like this - a trip to Kragen's in the works anyway for antifreeze in a bit, so I'll do some comparison shopping while I'm there. With tools not being part of the equation, my main concern is being able to air up from 16 to 32psi in less than 5 minutes per tire.

Any comments on running a setup like this, at least until I can afford a better solution?

Click to expand...

You should be able to find it cheaper at the store. Actually youshould be able to get two for that price. Wire one up on each side, and there you go, airing just decreased by 2.5 min.

I run the caddy compressors. They work fine for me when I need to air back up. I also have one for my ARB. If you ever wear one out, it's a $5.00 fix.

Dan.

Dingo509 said:

Why not use a york next to the a/c compressor? That's what i've done works great, 100% duty, i run air tools, fill air mattresses, and blow dirt out inside.
I relocated my battery the rear but if you move it to the driverside you have no problem with clearance.

You can see the York right next to the A/C compressor

Click to expand...

Dingo, how did you mount the York next the A/C compressor or do you have a picture of the bracket?

I was wondering what you did for a belt? Did you add a v grove to the alt? If so how do you tighten the belt?

Okay. Today's trip to Kragen netted a Superflow MV-50 - when I got there, they had them on special for $40, so I figured that it was probably worth it.

It's designed to be either portable or permanently-mounted, with a removable carrying handle (two hex bolts to take it off), and four rubber press-stud feet that pop out for permanent mounting. The downside: it's probably not the ideal candidate for underhood mounting, mainly due to the cheesy air filter that barely snaps together. It's also not the smallest of units, so may not allow the hood to close if bolted to the traditional bulkhead location on the passenger side. One possibility that came to mind was inside one of the cargo area panels and running the air fitting out through one of the grommets in the rear hatch.

It does a fairly good job of reinflating, going from 16 to 32psi in just on 3 minutes. It has a constant duty cycle of 40 minutes, so should easily refill 4 tires in under 15 minutes.

Anyway, time to take some measurements and figure out if there's anywhere this thing can be permanently affixed that won't kill it.