Is this bad? Also, whats the difference between turbo flutter, and flutterdump???

I know flutterdump is the BOV releasing a bit to late, is this different than turbo flutter, or is it the same? (sorry for the run on sentence)

In this link at like 22, and 40 seconds (also throughout the video) you hear what sounds like flutter...I always thought this was awesome, and only heard one Camaro that made this sound...Is this bad though?

If so what causes a)turbo flutter, and b)what causes flutterdump?

http://www.youtube.com/watch?v=Zrzq89y5K80

 

In the diesel word that is called "turbo bark" and it is bad for the turbo, but I have done it numerous times on my 500+ hp 800+ ft/lb duramax and the turbo is still in one piece. Diesels don't have a BOV so when you rapidly let off the throttle under high boost applications the turbines will rapidly slow down, causing the fluttering/barking sound.

 

Turbo flutter is boosted air hitting your throttle plate while under load, then it reverses it self and travels back towards the compressor. When the pressure hits the turbo compressor, it rapidly slows the intake compressor down, causing a flutter sound. (Usually there is still high pressure in the exhaust manifold which can snap the turbine shaft.)

Wastegate flutter is caused when the exhaust gases start opening the wastegate, causing inconsistent boost, or boost spikes.

Neither are good.

 

And one strong note for the diesel, it doesn't have a throttle plate to snap close and stop air from entering the engine. It uses fuel control to slow the engine, unlike a gasoline engine which uses air control.

 

My car does this under low boost. Is this something I should be concerned about? Its the BOV making the noise, is this the same thing as turbo flutter like in that vid? The BOV is a tial 50mm

 

What spring do you run in your tial?

 

Im not sure which spring is in it. I got it used and its whatever was in there. They guy I got it from was only running like 5 PSI.

 

Take it apart and check the color of the spring.