Post by Plankton on Mar 29, 2009 8:09:35 GMT -4
I'm in the midst of installing on board air in my TJ, and figured I may as well post up to serve as help, or a warning to folks who may attempt the same thing with their Jeep.
My TJ does not have A/C, so I decided to pick up an A/C compressor to use for my OBA. It just made my life easier with mounting and the new belt length.
My compressor is actually from a 4.0L Grand and did not come with the hose manifold. So I had someone fab one up to work within the available space. Here is a shot of it installed, with some temporary fittings on the side.
I'm using one 2.5G tank from an old 5G compressor. Kilo cut it in half and kept the other tank for his own OBA project. Big6 was kind enough to have an NPT fitting and mounting brackets welded to the tank. Yesterday, I went out and drilled the necessary holes in my floor and mounting brackets. The tank is bolted under the floor, opposite the muffler.
The tank has two 1/2" NPT fittings. One will be an input from the compressor, probably 3/8" line. The other will be an output to the rear of the Jeep.
On the dash, I picked up an extra switch panel from a TJ, used my trusty dremel to cut out my ash tray, and mounted the switch panel in it's place. The new panel now holds three new switches, and the connector for my CB mic. One of the switches will turn on the OBA system, which will then be controlled by a pressure switch under the hood.
I'll post up more pics and information as I go. Along with the details of what worked and didn't.
Edit: May 2, 2009. Installed hoses.
Finally got around to installing everything today. Big thanks to Bruce for coming in on a Saturday to make the hoses that I needed.
The current intake for the compressor is 1/4 filter and an inline lubricator. These are attached to the radiator support. Sometime this summer, I plan to replace the 1/4 stuff on the input with 3/8 to improve flow on the input side of the compressor.
A tight fit on the side of the compressor, but I was able to get the hoses, assorted adapters, and one-way valve on the output side of things.
Hose from the output of the compressor is teflon with stainless braid, rated for 450 degrees. The hose runs from the compressor, along the bottom of the grille and up to the left fender. In this picture, you can see the stainless braid along the bottom.
I mounted my (left to right on the manifold) oil/water separator, pressure relief, output hose, and pressure switch at the front of the left fender as it was one of the few places with enough room. Not much free space under the hood of a 4.0L TJ. This location also allowed about 4-ft of hose for heat to dissipate before hitting the separator. Granted, I run the risk of oil/water collecting in the hose, but so far it looks like air pressure is preventing that.
By the time I was home with the camera, I didn't feel like climbing back under the Jeep, so no photos of the hoses installed on the tank. You'll have to use your imagination... there is a hose from the manifold to the tank, then a second from the tank to the rear bumper.
I drilled a hole in the rear bumper, then used a bulkhead fitting and elbow to attach a coupler on the outside of the Jeep.
I will be using a rubber chair foot to cover the end of the coupler to keep dirt out.
It takes about a minute to bring the system up to 120psi at idle, but I'm losing about 5-10psi per hour when everything is off. Next nice day, I'll head out and check all of the connections with water to find the leak.
My TJ does not have A/C, so I decided to pick up an A/C compressor to use for my OBA. It just made my life easier with mounting and the new belt length.
My compressor is actually from a 4.0L Grand and did not come with the hose manifold. So I had someone fab one up to work within the available space. Here is a shot of it installed, with some temporary fittings on the side.
I'm using one 2.5G tank from an old 5G compressor. Kilo cut it in half and kept the other tank for his own OBA project. Big6 was kind enough to have an NPT fitting and mounting brackets welded to the tank. Yesterday, I went out and drilled the necessary holes in my floor and mounting brackets. The tank is bolted under the floor, opposite the muffler.
The tank has two 1/2" NPT fittings. One will be an input from the compressor, probably 3/8" line. The other will be an output to the rear of the Jeep.
On the dash, I picked up an extra switch panel from a TJ, used my trusty dremel to cut out my ash tray, and mounted the switch panel in it's place. The new panel now holds three new switches, and the connector for my CB mic. One of the switches will turn on the OBA system, which will then be controlled by a pressure switch under the hood.
I'll post up more pics and information as I go. Along with the details of what worked and didn't.
Edit: May 2, 2009. Installed hoses.
Finally got around to installing everything today. Big thanks to Bruce for coming in on a Saturday to make the hoses that I needed.
The current intake for the compressor is 1/4 filter and an inline lubricator. These are attached to the radiator support. Sometime this summer, I plan to replace the 1/4 stuff on the input with 3/8 to improve flow on the input side of the compressor.
A tight fit on the side of the compressor, but I was able to get the hoses, assorted adapters, and one-way valve on the output side of things.
Hose from the output of the compressor is teflon with stainless braid, rated for 450 degrees. The hose runs from the compressor, along the bottom of the grille and up to the left fender. In this picture, you can see the stainless braid along the bottom.
I mounted my (left to right on the manifold) oil/water separator, pressure relief, output hose, and pressure switch at the front of the left fender as it was one of the few places with enough room. Not much free space under the hood of a 4.0L TJ. This location also allowed about 4-ft of hose for heat to dissipate before hitting the separator. Granted, I run the risk of oil/water collecting in the hose, but so far it looks like air pressure is preventing that.
By the time I was home with the camera, I didn't feel like climbing back under the Jeep, so no photos of the hoses installed on the tank. You'll have to use your imagination... there is a hose from the manifold to the tank, then a second from the tank to the rear bumper.
I drilled a hole in the rear bumper, then used a bulkhead fitting and elbow to attach a coupler on the outside of the Jeep.
I will be using a rubber chair foot to cover the end of the coupler to keep dirt out.
It takes about a minute to bring the system up to 120psi at idle, but I'm losing about 5-10psi per hour when everything is off. Next nice day, I'll head out and check all of the connections with water to find the leak.