Has anyone done an on-board air system using a "Balloon Time" helium cylinder?  The cylinders are non-returnable, and I have two that were left over after a party.  They are steel, manufactured by Worthington Cylinder, and come in at least two sizes. 

From what I can learn on line, they have a working pressure rating of 260 PSI and are proof pressure tested to 325 PSI.  Is that enough?  I haven't tried finding a fitting that will fit the tank outlet yet, but it looks like a standard thread. 

What do you think?

That seems awfully large to shove under the hood.  Or are they smaller then they look in the photo?

Any air tank should work, what are you planning on using for your pump?

You are right.  Unless I would put it in the back end, there just isn't any good place to mount it.  I think I'll go with the pressurized PVC tube bumper.  I will be using the converted AC compressor with oiler as others have used.

I think I'll go with the pressurized PVC tube bumper.

I wouldn't if I were you - the first time you hit something with it pressurized it'll explode like a pipe bomb.

You're right...   ...rethinking...