I concur with the other suggestions that you may not have a strong enough motor, and/or, leaks.

Can you possibly tell us a bit more about what you're connecting the system to? i.e. diameter of the ducting/piping, or of the power tools you're connecting it to?

Also, if you could post a few pictures of your system, etc. that might be beneficial for us to give additional feedback and ideas.

~ "Mr. Measure Twice"
'A day without sawdust is like a day without... air to breathe!'