Mine does it also...pretty much all open filters will. Like everyone said most like the sound...yes it kind of sounds like a turbo. Personally I love the sound

my other car has this one on it...

K&N RX-3990-1 "X-Stream"



You think yours makes noise you should here this one whine/whistle it really sounds like a turbo



Scott 2000 Contour SVT #1464 Mustang Dyno: 171.6hp/145.3lb Dynojet Dyno: 171.1hp/148.9lb 1989 20th Anniversary Turbo T/A "Indy 500 Pace Car" #1376 of 1550 All Original, 46k with a few mods 2002 F150 SuperCrew