Dump Valves... EEEK!!!!!
I drove my first turbo powered car a few months back, a Fiesta RS Turbo, Within 100m the hiss it uttered every time I changed gear was driving me crazy!
Gee, I must be getting old

It reminded me of the time, a LONG time ago, when we used to peg playing cards to the rear forks of our bikes so it clattered against the spokes making a roaring noise vaguely like a motor bike
Same thing, I guess, making something sound like something it isn't
