Wen ya take dv off and block the pipes it makes a much better noise than whoosh so what do you call that? And wastegate chatter ive heard a millon time over the years so must of come from somwhere?? Ive got a a piperX filter and carbon pipe.
IF you were to block the pipes and remove a DV, all you are doing is storing boost when you lift off, which in turn fights the compressor wheel in the turbo causing it to stall (compressor stall) and you get a sort of fluttering/pigeon noise.
this is BAD for the turbo, it puts lots of un-natural forces on the comp wheel and the shaft, rather than it being able to spin free.
this is why all turbo cars are fitted with DV's as standard, to dump this boost and empty the boost system so the comp wheel is able to spin free with no pressure opposing it.
if you actually knew what a wastegate was, i suggest you research it, you'd realise that there is no such thing as 'wastegate chatter'.
some complete spaz of a chav has obviously come up with the term at some point and his chav following have continued to use it.
cars, particularly jap cars, that make that noise are fitted with atmospheric DV's (blow off valves), and are designed to make such noises, some of these blow off valves even offer different attatchments to change the noise to whatever you desire. Some HEAVILY tuned cars, running so much boost also make this noise when lifting off on part throttle, you may see some cars rev a little and wooshwooshwooshwooosh, they will 'chatter', this is due to the amount of boost they run and the hhhhuge dv they require not quite getting rid of all the boost in the system, again giving compressor stall.
there is no way on these cars, unless you spend a fortune in tuning and stand alone ecu's and run mafless with lots of boost that you will make a similar noise.
all you can achieve is a standard 'ptsshhhhh', enhanced by a large open cone, increased boost, an aftermarket RECIRCULATING dump valve, and perhaps some sound deadening material removed from under the bonnet.
hope i've cleared it up for you