[cdigerlando]

I'm not a mechanical engineer, I'm an environmental engineer, but commonly I deal with pumps in parallel or pumps in series. One thing you could try when you are operating two compressors in parallel is to recalculate the graph doubling the flow, and keeping the pressure constant. I don't know how applicable this is, since air is a compressable fluid, and I mainly deal with noncompressable fluids, but you could try it to get in the ballpark range of what you are looking for. That gets back to what Mike was saying, by not doubling the boost but doubling the flow.