-   XJ Cherokee Technical Forum (
-   -   A/C to OBA conversion write up -PICS (

RussoGuitar 10-09-2007 05:28 PM

A/C to OBA conversion write up -PICS
Ive really needed on board air for awhile now and i finally got around to doing it. I had three main options: An electric compressor, a belt driven compressor, or a C02/Nitrogen tank. I decided on a belt driven compressor for a few reasons. They put out way more CFM then an electric compressor, theyre quieter then an electric compressor, they have a 100% duty cycle, and if done right will probably be cheaper. I also seriously considered using a C02 tank, but one drawback to having a C02 tank is that it will obviously need to be refilled periodicaly, and with amount of air ill be using a C02 tank just wouldnt work best for me. As for what type of belt driven compressor i was going to run i had to decide between a York, or my stock A/C compressor. I dont use my A/C often and due to condensor issues it has never really worked properly. I figured this would be the easiest/cheapest route since the compressor was already installed, i just needed to do the plumbing. The stock Sanden compressor puts out about 8-9 CFM which is quite a bit, especially compared to the expensive electri compressors that only put out 1-2 CFM. The highest rated electric comp i could find is the Extreme Air compressor, which goes for about $380 and puts out 4 CFM at 0 psi. Anyway on to the install..

I started by removing all the A/C hoses and fittings. I then used some 3/4 to 3/8 pipe reducers on the input and output of the comp.

Then came the intake. The Sanden compressors are lubricated by the freon in the A/C system. With no freon you have to have an alternate way of lubricating the conpressor. The most common and efficent method is to use an inline air tool oiler, which is what i did.
Heres the intake, i used a valve cover breather fiter as an airfilter-
Now for the output. The output goes through a check valve, then through an air filter and seperator. The idea of this is to collect any condensation an oil that gets through the compressor. Not totally neccesery but its good to have. The line from there splits at a "T", one line goes to my front airline disconnect and the other goes to the rear of the jeep to the tank and manifold.
Under hood junk complete:
Next was to assemble the Manifold. I could have used the tank as a manifold since it has 6 ports on it but this manifold would keep thngs neater, more organized, and i wouldnt have to worry about braking a guage or somthing off the tank when putting tools and such in the back. I purchased the manifold for 12 dollars on
Here it is assembled.. saftey reliefe valve, pressure switch, and gauge.
I go the tank and pressure switch on ebay for an awsome deal. 50 bucks for both. The pressure switch is the Kilby switch, which turns on at 120psi and turns off at 150. Higher then neccesery but the price was right, and the only other small pressure switches i could find shutoff at 105. Id rather be high then low in this case. The tank is the Viair 2.5 gallon tank. I mounted the tank and manifold where the spare tire used to be which made for a clean look and didnt take up any useable space.
Tank and manifold mounted and lines run.
Now all i had to do was wire it up and i was good to go. I put a switch on the console which then runs to the pressure switch.
All i do is flip the switch and the compressor kicks on until the system reaches 150psi, it turns off and wont kick on again ill it gets to 120. The system pressurizes very quick. From 0 to 150 psi takes just over a minute. I havent got an exact time but it filled my 33x12.50s from 9 to 32 psi in about a minute as well.

Front connect:
Rear connect:

RussoGuitar 10-09-2007 05:30 PM

No useable space taken up by system:
At 150 psi and 8 CFM the system runs air tools just as good as my 12 gallon shop compressor.

All in all im real happy with the system, its probably one of the most useful mods ive made to date. Everything used can be bought at a local hardware store or home depot or lowes. Total cost was $125.

crosbike3688 10-09-2007 06:04 PM

Great write up man!!!! I will definitely be doing this in the near future.

What exactly did you do for wiring? Im electrically semi retarted.

rocketman121 10-09-2007 06:19 PM

RussoGuitar, did you get the A/C system drained by a shop? Or just remove the OEM hoses by yourself.

Red Raider 10-09-2007 06:34 PM

what an awsome write up!! for sure many people, including myself, will be attempting this.

thank you

abnormal 10-09-2007 06:36 PM

This is just what I want to do. Great writeup. Could you list the parts that are needed? Do you switch the ac on to make the compressor pump the air or what? I guess I have to do some research.

RussoGuitar 10-09-2007 06:57 PM

Thanks for the comments...
For the electrical questions i simply disconnected the wire the magnetic clutch on the compressor. I ran 12 volts right from the battery through a 5amp inline fuse. The wire then goes to my switch on the console, that switch goes to the pressure switch, which goes to the comepressor clutch. So when i flip my switch it supplies 12 volts to the pressure switch. If pressure is below 120psi the pressure closes which engages the compressor and it automatically shuts off at 150 psi.

RussoGuitar 10-09-2007 06:58 PM

opps, double post on last reply, JF is super slow tonight.

law.74 10-09-2007 07:10 PM

Having mounted the tank on it's side how will you drain it, short of dismounting it?

RussoGuitar 10-09-2007 09:13 PM


Originally Posted by law.74
Having mounted the tank on it's side how will you drain it, short of dismounting it?

I dont actually dismount the tank, bought i do take a few screws out of that panel to where i can just angle it to the drain **** which is on the end. Its pretty quick and easy. There was really no other good way to do it, i considered welding a bung in for a drain on the "bottom" but didnt feel like it and this works just fine.

rocketman121 10-09-2007 09:16 PM

Skip over my question?

RussoGuitar 10-10-2007 07:09 AM


Originally Posted by rocketman121
Skip over my question?

ha sorry, totally missed that. My condenser had a leak so at the time there was no freon in the system.

texinteg 10-10-2007 08:32 AM

I plan on doing this in the near future.

Tweeternpi 10-10-2007 09:07 AM

Man that is a Great write up, I know what I am going to be doing with my AC pump. My Condenser went on me this summer. The would be a great mod for me as I autocross a car as well would be nice to be able to fill up tanks or use air tool at a race.]

should be a sticky

Tweeternpi 10-10-2007 09:07 AM

Doulbe post.

Can you get a parts list for all of us who want to do this mod?

The time now is 08:16 AM.

Powered by vBulletin Version 3.8.8
Copyright ©2000 - 2017, Jelsoft Enterprises Ltd.

User Alert System provided by Advanced User Tagging (Pro) - vBulletin Mods & Addons Copyright © 2017 DragonByte Technologies Ltd.
vBulletin Security provided by vBSecurity v2.2.2 (Pro) - vBulletin Mods & Addons Copyright © 2017 DragonByte Technologies Ltd.