AC compressor for onboard air

[Junkie]

Has anyone set up the AC compressor to act as an air compressor? I never use my AC and have had the condenser removed for at least 6 months. I'd like to be able to air my tires up and maybe even use air tools every now and then. I know that I'd need a filter and then something to oil the air before the compressor, and then a manifold with fittings and a pressure regulator after the compressor (and maybe an coil separator). 

 

I'd consider running it to a tank, I know that a lot of AC compressors run on the order of 300psi so either I'd regulate it before the tank or use a high pressure tank (intended for SCUBA or welding or whatever, and capable of much higher pressure). 

 

How would I control the clutch on the compressor? I wouldn't want it running all the time of course. I suppose a manual switch would be fine, but don't know which wires on the compressor do what. 

 

If it matters I have a 99 Legacy Outback, which uses a compressor designed for R134a. 

 

Thanks for any help. 

[Fairtax4me]

Just use a standard compressor pressure switch.

http://m.northerntool.com/mt/www.northerntool.com/shop/tools/product_22938_22938?cm_mmc=Google-pla-_-Air%20Tools%20%2B%20Compressors-_-Air%20Compressor%20Accessories-_-16151&ci_src=17588969&ci_sku=16151&ci_src=17588969&ci_sku=16151&gclid=CNqB1Pfgw74CFdF9OgodsSYAOA Use it in conjunction with a manual switch to engage the compressor clutch only when pressure gets low.

 

An old scuba or oxygen tank would work well, and would be tough enough to withstand damage if the car ever got wrecked.

 

 

The compressor does hold oil, but it also pushes the oil around through the whole system. I think you would need a way to catch it and route it back to the compressor so it doesn't just blow into the tank, then the compressor would burn up.

A lot of Jeep guys use the old Tecumseh box compressors for air so it can certainly be done. Check out some of the off-road and 4WD forums out there because I'm sure someone has done this.

[Junkie]

When it comes to engaging I was mostly wondering what wiring needs what in order to engage the clutch. I'm sure I can figure out a way of turning it on and off. 

 

I agree on a scuba or welding tank, I think I'll be able to find one pretty cheap (or might use one I have)

 

I'd rather use the factory compressor rather than one from another car if possible. That makes mounting and belt very easy. I don't expect I'll use this very often, so a small oil reservoir would likely last a long time. Or, I could have the inlet (with the oiler) lower than the outlet (with the oil separator) so that it automatically recycles the oil. 

 

I know other people have done similar things, I was curious as to whether anyone has done it using the compressors that Subaru uses. 

 

One of the main questions I have is what pressure the AC compressor will put out. 

[Crazyeights]

Air horn tank from a large truck works well.