How to make Audi go stututu (Turbo Flutter)?
Do you want your Audi or Volkswagen to sound like a Toyota Supra or any J2Z car?
Does it sound basic when you rev your Audi and you want the extra turbo flutter? The “stututu” noise for those of you that don’t know yet is a turbo flutter. The turbo flutter noise is produced while the turbo is operating in compressor surge, as the compressor 'chops' through the air rather than pushing the air into the engine.

Disclaimer
This is a DIY method and will require 0$ and no extra car mods such as sparking plugs or air filters for you to do. Unfortunately, unplugging the devertive valve will cause turbo issues and we do not recommend you drive daily without the devertive valve. You can unplug one or two times to enjoy the turbo flutter.
For better results a cold air intake would be the best option with the lowest budget.
Steps
Locate your devertive valve
Devertive valves for Audi and Volkswagen are located at the rear of the engine, driver side closest to the turbo. For the biturbo engines you would normally have 2 devertive valves so make sure to locate both.
Unplug your devertive valve
Make sure the car is turned off .There is no need for you to remove the battery terminal.
The devertive valve unplugs fairly easy. Once removed you will enjoy the turbo flutter noise.

https://aaaccessory.com/car-air-filters/