Do superchargers make a blow-off sound?
 

Was watching the movie "my mom's new boyfriend"

theres a saleen s281 in the movie, it appears to be making a blow-off sound, even though its a supercharged car......

They have a by-pass valve but as a rule no not a BOV or dump valve. This is because as the blower isn't exhaust driven it doesn't suffer LAG/Stall periods in the same manner.

Nope. Not unless the engine's about to llift the blower off and then you don't want to be nearby anyway.

This is a little blower lift (found on a search). A big one is very nasty..!

Video of Blower EXPLOSION - Photobucket - Video and Image Hosting

They can: depends on the type. They can also make the chatter noises often associated with a turbo fitted without a BOV.

Centrifugal types generally sound like turbos the most - especially if its overdriven. As essentially it is a turbo compressor wheel driven by a gearbox+pulley instead of the exhaust wheel.