There was a somewhat similar post regarding raising the PSI of a compressor but it doesn't provide an answer to this problem. For various reasons I need to use a very portable cheap tire inflator type compressor. It's ~1 CFM and can inflate to 150 psi maximum pressure (very slowly!). I need to use it to run a venturi type vacuum adapter. It requires 80 psi to pull full vacuum (27.5"Hg). What I'm hoping to do to make this work is to have a small chamber in the output line. The idea is that it will fill to 125 psi and then empty thereby producing a sustained burst of high PSI air. The PSI curve should tail off but there always needs to be a little pressure so that air doesn't rush into the venturi vacuum adapter backwards (alternatively I could use a check valve in the vacuum section of the line to prevent this back flow but fewer parts is preferred). I imagine that some kind of pressure release valve would work but I don't know exactly how they function. When the inline expansion tube hits 125 PSI it should trip and then snap shut at around 60 PSI to enable the next cycle. I'm looking for someone to help me identify what part might be able to accomplish this. Thanks!