Turbo spool sound question

[Melow]

Ok, quick question. I'm between the Hybrid and S280. One question I have is, when you get off the gas and the turbo is spooling down, sometimes you hear that "whine" a it slows. Do both those Rittenhouse have that sound or is it usually just from bigger turbos? I know it's just a minor thing and not anything to do with performance, but I dig that sound.
I'm running Cobb cai, catless downpipe, 2.5" Cobb catback, ( looking to change that), and GFB dv+. Thanks

 

[slopoke]

Typically, you hear the "whine" while the turbo is spooling up and building pressure. I don't remember hearing any turbo whine on decel, because the turbo should be slowing down.

In terms of a BOV, If you have a recirc system, you won't hear anything on letting off the throttle, because it's venting back to the compressor inlet. If you have a blow off valve that's vent to atmosphere, you will hear a whoosh noise on letting off of the throttle

 

[The_Ryan]

All turbos whistle when they spool down. I agree it's a pretty sweet sound, some turbos may be louder than others. I'd assume that sound is louder with larger turbine/housing turbos. The factory turbo does make that sound but it seems to be attenuated by most cat-backs. I've only heard it through Milltek and MBRP exhausts.