pilchardthecat said:
Exdos - have you plotted static pressure vs speed/rpm in the factory airbox?
(i dont care which side of the filter - of all the things that cause a pressure drop the filter is probably the smallest one)
I've not plotted this as a graph, as such, but I have recorded it as a video with the combined use of my datalogger and a Magnehelic pressure gauge and you can see what happens here:
http://youtu.be/RzyV4g9KK7M In this recording, my Z4MC was completely OEM.
The graph below is the theoretical increase in static pressure versus velocity: i.e. "ram pressure". As you can see, the pressure inside the air intake (as recorded by the Magnehelic gauge) is varaiable at any given speed dependent upon gear ratio, vehicle speed and throttle opening. As my video shows, the OEM kit is very good to start with but it still can be improved some more.