[rotrex]

What's the HP target? This SC seems good for some 300HP, so about 250g/sec of air, for a pressure ratio of 2, so a tad less than 1 bar of boost. This suits to a engine with NA power of about 150HP.

The first diagram shows the efficiency over airflow and pressure ratio. You need about 100g of air per second for 120HP. The lower the efficiency the hotter the air gets out of the SC. The second map shows what percentage of the theoretical volume of the SC is expelled per revolution. Say it pumps 1liter per revolution and vol efficiency is 89%, you only get 890ml of air out per revolution. Pressure ratio is the ratio of output pressure and input pressure, both on the absolute scale. So athmospheric, 1bar absolute, in and 2 bar absolute or 1bar of boost out is 2/1=2. There always intake losses, so your real PR is always a tad lower (10-15%) than the ideal number.