Blowoff valve?

Please forgive me as this may seem like a basic question to many on here. I’m no diesel mechanic I’m more used to customizing gas powered motors/cars.
Do turbo Diesel engines have a blowoff valve which releases boost when off the gas pedal? I know many/all gas turbo engines do and they add a nice sound when driving so I was thinking about getting one for my jetta if it’s even possible.

The main reason I question if my 2015 jetta tdi ever completely releases built up boost is because I always hear the turbo (even when just letting the engine slow the car down from high rpms, I still hear a little whine when off the gas). I have a boost gauge which supports my hunch as it still reads a few pounds of boost when the car is in gear just coasting.

If anybody knows about this or can recommend a blowoff valve (if they apply to tdi motors) would be greatly appreciated

As far as I know, when there is no throttle body then there’s no Blow off valve.

Short version: save your dollars. Not worth the trouble or expense in trying, and may actually cause problems even if you could do it.

It's not a Subaru... don't treat it like one

X2 what andrei said. Your car has a variable vane system (VNT) built into the turbo, which regulates boost. It is powered by vacuum and controlled by the ECU. Don't mess with success...

Just thought I’d ask since I thought I could maybe make some cool sound aside from an exhaust. Alright then that’s that.

Thanks for the diesel education!

There is a throttle flap on both the intake and the exhaust, as well as a complex EGR system. Not much "noise" to be made anywhere, and the purpose of a pressure relief valve on a gas turbo engine is to release a rapid jump in pressure between the turbocharger compressor and throttle flap when the throttle is suddenly closed. But the diesel doesn't use the throttle flap in that manner, so there is never a giant turbo damaging spike in air pressure in the charge air tract.