Poor Mans On-Board Air
 

I started with a High Volume Auto Air Compressor from Harbor Freight. It cost me $49 online. It's numbers aren't that different than the Viair 400 series compressors... I know, quality is different. But then again, this is a poor mans on-board system...
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I then found a regular air compressor on sale for $56 in my local Harbor Freight store. That was a really good deal since the sale had expired but nobody told the staff. They were gracious enough to give me the sale price.
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I removed the 120v motor and disconnected it from the tank (leaving the regulator, pressure release valve and gauge)... Since every compressor is slightly different I'll leave this step up to you. Just remember to keep it unplugged and make sure all the air is out of the tank. If not, it will either hurt you or scare the piss out of you...
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I removed the base of the Auto Air Compressor to make it easier to work with. I then located, marked and drilled holes so that the tank inlet and the air pressure switch (other side...not shown) could be re-attached once the new motor was mounted. I also drilled additional holes that would allow me to mount the new compressor to the tank. In this case I used one wing nut on each side for easy removal just in case I decide to go with a different set-up. I was lucky enough to find a tank with a mount that was just right. worked out great...
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I used a longer 1/4 inch copper pipe with compression fittings to attach the tanks inlet to the compressors outlet. Notice that I used a quick release instead of just making a more permanent fitting. I did this with the thought that I may want to change the set-up later. Otherwise you could simply remove the male quick release connector from the compressor and screw in a more permanent fitting.

Here it is... I can carry it from one vehicle to another and use the battery cables that came with the high volume compressor. It fills the tank to 110lbs in about 2 min 30 sec. Once the tank is full, I can fill one tire (32s) from 20lbs to 40lbs in about 1 min 30 sec. By the time I've moved to the next tire the tank is just about to capacity again and I can start airing the next tire up.
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The total cost was $105 because I happen to have the pipe and compression fittings I needed handy. If you compare the CFMs with similar Viair systems you will find this pretty competitive (1.35 CFM @ 40 psi 1.05 CFM @ 90 PSI). If you were to buy this from Viair I would think it would cost about $250 ish. If I were to just purchase an inverter that would allow me to run a regular compressor, I think that would cost me about the same because of the wattage requirements. All said, I think (THINK) I saved about $100-$150. If not, I had fun building it so it was still worth the effort...

on-board air
 

thats awsome. i was once thinking of a way to make onboard. i too have that same exact pump from harbor. i got it on sale a few months ago. so it does work about twice as fast with a tank ?

Me do something like that for my 2 cyl. compressor I got on E-Bay (E-Bay item number 130184534947) when it arrives. Thanks for the idea!

take it one step farther and buy the chrome compressor from harbor frieght and then buy the tank you just fill. it would definately be cheaper than buying 2 compressors. i use one of those tanks you just fill for kart racing. now i am only making 1 to 2 psi adjustments, but it will last me all day.

Nice job!

I'm working on something too w/ the JCW compressor pictured above. I didn't get it at JCW though, I found it somewhere cheapr online. About $50 shipped I think.

The real benifit isn't necessarily the increased time in airing up a tire. I usually fill the tank at home before I leave while I'm doing other things. So I'm not counting the 2 or so minutes I spent on the initial fill. However, I did a real test and went from 15 to 35 PSI on the first tire in 1 min 10 sec. It took the about 1 min 40 sec to fill the tank back to capacity and the same for another tire and so on... The reality is that the air compressor by itself is probably just fine. The tank add on probably saves you the time it takes to air up one tire which isn't much (it's the same for viair systems by the way).

On the other hand, the reason viair systems with a tank is so desirable is that the tank allows you to run power tools, air off dust or water from hard to get places and other uses that High pressure gives you. I went with a small tank which in itself has problems of it's own. I'm thinking of a 3-4 gal tank but only if I come by one at a yard sale or something.... I am afterall...broke....:sad2:

you can find viair 2.5 and 5.0 pound air tanks on ebay all the time for less than 50 bucks if you want a larger tank

I have this same compressor, i bought it at Costco wholesale for like 50 dollars. It works great, runs cool and high volume is right. It airs up tires pretty quick and its pretty quite too. I'm really happy with it, and since it came with a bag to keep the hose and accessories organized, i know i won't lose anything.

Wow... I was planning on doing this same thing. I already have the 110Volt compressor and tank. The motor went bad (i did finish nailing all of the vinyl siding on my house before it keeled over:yup: ) Do you think there is enough space on top to mount 2 12V compressors? (extra fast air up)

Probably not without modifying it. Two 20" pieces of steal should do it. Maybe 2"x1/4". The compressors could be mounted face to face. That would be kind of cool. Post pics if you do it.