If it is a 2 cylinder compressor, is it one or two stages? That is, are the cylinders piped in parallel or in series? If in series it's to improve the efficiency in reaching higher pressure. And you would get just half the capacity calculated by FLJ, above. Plus any compressor has an efficiency, guessing around 60 to 80% on a small one like this. So starting at FLJ's 2.73 CFM, multiply by say .6 to get an actual capacity of 1.64 CFM. AND this is INLET capacity. The discharge capacity is much less, by the ratio of discharge to inlet pressure, and the ratio of inlet temperature to discharge temperature, in degrees absolute (Fahrenheit + 459.6 = degrees Rankine).