250 CFM is what our engines need at about 3800 RPM. So after that, the "supercharger" would kill airflow. There is actually an electric supercharger that provides 1 PSI. Basically it overcomes the drop in pressure from air tubing and will help bring cold air to you engine giving a real 5-10 HP. Even teh best factory ram air provides less than .5 PSI. It draws over 800 watts which is almost 60 amps. It only works at WOT and for short bursts. Road racers have found these to be great power adders. They provide

http://www.electricsupercharger.com/products-eram.html