HomemadeTurbo - DIY Turbo Forum

My car has been running perfectly for the past 5000 miles boosted. (t3 .42/.48 10 psi...df16y8...crome basemap...dave blundell checked out the plugs and made a few modifications to it, but couldnt tune it cuz the turbo was smoking so he counldnt wideband it)
Now to the problem:
Well yesturday I changed the oil, plugs and put in a pre turbo pipe and filter (was just running window screen)

Now when ever i get on it i hear an unusual noise..ba-bum kinda sound...not very loud..kinda a high pitched sound...occurs after the bov goes off

So, my question is....any ideas wut could cause this? I've never heard detonation before so I have no idea, but I always imagined it being loud and low pitched, or maybe its just the engine moving and making the intake pipe hit? Maybe it has something to do with the gap?(BKR7E's gapped to .030...will pull them and check the gap tomorrow)
Pic of the bay/location of filter (click thumbnail for full version)

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