if it is a boost leak of that much, you will see a lot of black smoke out the tail pipes at the same time,(perhaps when you do it, have a quick glance out the rear vision mirror and see if your blowing clouds of black smoke). I've had a boost leak before that took some heat and pressure to show (and it did make noise when it did it too), it turned out to be a loose hose clamp and the silicone joiner would make the noise as it ~flapped~ while leaking.
09:15:50 10/23/17
