when you let off the pedal quickly you have all that boosted air that is no longer being pushed by the turbo compressor and not being consumed by the engine. and it wants to exit back out the compressor. this is against the spinning of the compressor wheel and making it want to rapidly change direction of rotation. i couldnt tell you exactly what side (hot or cold) is making more noise but basically everything is trying to reverse direction quickly. depending how quickly that boost leaves you may notice a "bark"...so, when getting off the fuel go nice and easy and keep your turbo happy.

*gman07 beat me to it

 

i second this...

 

Hey guys, ive got what i beleave now to b a wastegate problem too. Ever sence i put the motor in my boost gauge bounces up and down 3-4psi when ever boost gets to 25 and up, like a leak.

I drilled the center divider out and unhooked the wastegate and put a blank in the head( gutted afc). Now is this going to create enough back pressure to force the wastegate open and create a flutter and cause my problem u think??

Also i get a rapid taping that kinda sounds like it could b the flapper door. Ive been trying to trace the sound down now sence i put the motor in and its really pissin me off. Put a new overflow in no help, took the lift pump off and hooked the stock electric superduty pump back up and no change. Btw it only make the tapin sound at 2k and over and under load.

So u think a simple turnbuckle is the whole problem Any input would help alot thanks Jesse

 

Hey question this might sound dumb but i am a rookie with all this and i just hooked up the quadzila commander on my truck and by reading everything here i might have a wastegate problem.
Why do you think that you may ask?
Well when i am doing about 70 mph the boost jumps around in the teens there are times i cant even tell what number it is on becouse it jumps so much, what can i do to fix this?
Where is the wastegate and what do i do to it?

 

Just for gee whiz.. Compressor stall will happen in an axial-flow turbine engine when the angle of attack on one or more blades becomes excessive and the smooth airflow is disrupted.
Compressor surges occur when there is a complete stoppage of air or a reversal of airflow through the compressor. Surge is what's happening here. I think it would be worse if diesels had throttle plates to stop the airflow like gassers do.

 

have you seen one bark so hard that it stalls the engine and you have to bleed the injectors to get it running?