I've had a greddy RS BOV (non recirculating) running in my setup for a while but after pulling the motor and replacing some the timing belt it, or the turbo, makes the classic but deadly turbo choo choo sound known as turbo flutter or turbo surge. Being that it did this the first time I thought instinctively that the blow off valve was set to stiff so I softened it up and it still however makes the flutter noise from the turbo or the blow off valve I don't know which. At this point I have the set screw nearly turned all the way out of the turbo and it still makes the noise, I even had to turn it back in a bit though because it was starting to give me a boost leak. Anyone know what is happening? Is this normal?