I just put a used HX35 on my truck, and its doing great so far, but i wondered this with my old wh1c, and this turbo. If you get to about 15lbs of boost, and you are accelerating(with an automatic), and you let out of it real fast it will make this awesome bone chilling sound. Its not turbo bark. Its kinda like when you are shifting with a manual, and it makes the woosh noise; except this seems a little louder/more noticeable. I have heard many trucks do it. Anyway. Since my old turbo went out, im paranoid about making it make that sound; but i dont think its hurting anything whatsoever. I dont plan on doing it all the time, but i love the way it sounds, and my friends love hearing it too. Anyway. Do you guys know what im talking about(hard to explain), and will it hurt anything? Thanks

Eric

 

It's called turbo bark and is caused by the boost running backwards though the turbo when letting off of the accelerator rapidly. Don't think you'll see any problems with it as long as you aren't barking it with 40+ psi of boost. At high boost it can twist or snap the turbo shaft.
Even at low boost barking can blow the airfilter off if it's the type attached with a hose clamp, keep your eye on the filter if you like to bark it.

 

I Agree. Whether it's a "woosh" or a "woof", it's still backpressure from unneeded compressed air...causing rapid deceleration of turbo rpm and putting stress on the shaft. Not the best thing for it.

RJ