Is there a chart showing the relationship of volume flow rate to pressure in a cheap auto air compressor?
The best place would be the manufacturer itself, they might have tech specs or a white paper (document of technical specifications)
Air Compressor's? Anyone Have an idea?
Look at getting a 10-15 litre compressor direct drive as they are very easy to carry around. Perfect for nailing.
Refrigeration compressors from Thailand?
Well, Thailand is a third-world country so people will work for pennies there. Not many quality products come from Thailand. I have doubts about your compressors lasting a long time, but hey, who knows, what do i know.