Raul,
Referring to some older charts I find the following (which may only apply to direct pressure machines and may be different for suction type nozzle):

nozzle - 1/2"
air pressure - 20psi (2.8 bar)
shot - S-230 shot
intensity - .009A.
air volume - 90 CFM
media flow rate - 90 lb/minute (40 Kg/min)

What is the size of the air pressure hose?
What is the size of the media hose?
What media flow rate are you achieving?

Hope this helps

Jack