I use the cap of a spraycan and fit a valve in it, the one where you can presurise you car tyre with. Then remove the hose from airbox to turbo and fit this cap in a piece of 60mm hose with some good clamps and put this on the turbo. This way you set the pressure on the whole system including the turbo. Then put 2.5 Bar to it and listen for any sissling noices. You will be surpriced how much leaks you will find!