How do you cock up a turbo setup? You put a rubber chicken on the blow-off valve.
Blowoff valves (BOV) are just pressure relief valves designed to let off excess pressure or air, and in a turbo setup you’ll find this component placed right before the throttle body.
When you have a BOV you’ll hear a hissing sound whenever you lift off the accelerator. That sound is produced because when the throttle is closed, built up pressure and air from the turbo has to be diverted elsewhere, in this case the atmosphere.
When you put a rubber chicken on the outlet of the BOV, the effect is almost the same as blowing into that rubber chicken. In fact, if you put any sort of woodwind musical instrument at the end of the BOV, you can expect to make those specific sounds anytime you lift off the throttle! Here’s a mad scientist diverting his world domination aspirations into the automotive realm.