the best way is to cap off the pipe that goes to the throttle body, and cap off the turbo inlet. find a way to get an air fitting on one of the caps and pressurize it to about 20psi. there should be no leaks at all. doing it this way makes it pretty easy to find where the leak is. if this test proves nothing, try putting some soapy water on the piping connectors and clamps to see if its a small leak.