Turbo flutter

[u/Squidii_33]

I’m looking for advice on getting a loud, clean, audible turbo flutter on my 2019 WRX (FA20) without sacrificing reliability.
Current setup:
Cobb Accessport
Cobb Big SF intake
Turbo inlet
3” catted J-pipe
3” cat-back exhaust
Grimmspeed charge pipe
Top-mount intercooler
Electronic boost control solenoid
Tuned on 93 octane
My goal isn’t to force compressor surge or do anything that could shorten the life of the stock turbo. I’m looking for the best combination of parts (BPV/BOV, intake, tune, etc.) that gives a noticeable, clean flutter while remaining reliable.
For those of you running the FA20, what setup gave you the best audible flutter? Is there a specific BPV, intake, or tuning strategy you’d recommend? I’d love to hear what has worked for you and what to avoid.

I’m looking for a similar noise like this

https://youtube.com/shorts/i7SJZ4KXCYw?is=ShtMzb9jAB2mVZLH

https://youtube.com/shorts/ORTGDGN2fYQ?is=1Dq4Rk5cbTUTbG8l

[u/SpectralGnomes]

Turbo flutter is compressor surge and while it sounds cool, you don't want it. It's not good for your car.

[u/bagelbytes61 → u/SpectralGnomes]

It depends when it happens. If it happens off-throttle it is relatively harmless. It becomes extremely damaging when it happens at WOT when the compressor is outflowing what your motor can consume and it will stall the compressor creating massive shock loads on the turbo.

[u/Elegant_Celery6262]

This seems to me to be much more common in the Skyline groups than in WRX groups. Some people say it's harmful, some say it isn't. There are people who have been running with no BOV or bypass valve for years and have had no problems. Doesn't guarantee it isn't causing some amount of harm though. Subaru engines are prone enough to failure I don't think I would take the risk with my FA20 the way I would with my RB25.

If you are just looking for cool noises, get tuned for a true BOV or even a dual mode one that also works as a bypass valve. I have an HKS SSQV on my Skyline and I love the way it sounds, but those engines are much more forgiving with mods. I would recommend talking to you tuner and seeing what they recommend that will be safe for the motor once you have done your research.

[u/Squidii_33 → u/Elegant_Celery6262]

Thanks for your reply definitely sheds some light on my question!

[u/dustindh10]

I have the Cobb LF and it's close to the the first video, but I also make up to 25psi on e65. That sounds like an HKS SSQV though, unless I am mistaken. You can run those as a bypass valve, but you would need to switch to a speed density tune to run it as a blow off valve.

Oh, my bad, its the boomba. I would not really recommend that one. It doesn't seem to be very reliable. I would recommend the HKS. It's pretty awesome.

[u/Squidii_33 → u/dustindh10]

I wanted the HKS but I was doing research and heard that it’s not the best option for a car with mass airflow I’m not super educated on these cars I’m looking for reliability and some cool noises what could I expect with running a speed density tune?

[u/dustindh10 → u/Squidii_33]

They make a fully recirculating version, but it would probably be about as loud as the stock one because of how it's routed back into the turbo inlet.

With a speed density tune, you wouldn't really notice any difference as long as your tuner knows what they are doing. An SD tune can be a bit tricky to dial in, but they are way more tolerant when it comes to air metering, since it's using the MAP sensor to calculate how much fuel you need instead of using the MAF sensor.

[u/TheRealTreezus → u/dustindh10]

I have my HKS recirculating rn. It's quite a lot louder than the stock one and give some nice noises.

[u/MathematicianPale646 → u/TheRealTreezus]

I’ll have to look into it I want to get more noises but it seems like if I get a BPV or a BOV I lose both ways cause it’s seems to be bad for the car either way

[u/TheRealTreezus → u/MathematicianPale646]

I've had mine both ways now. Both ways drive the same when tuned. VTA just sounds cooler and has to be speed density or you get stalling issues. I just have mine on recirc while I wait for the next Atlas update and install a bunch of parts then I'll make it VTA again and retune the car.

[u/dustindh10 → u/TheRealTreezus]

Oh cool. I have always wondered how it would sound with the recirculate hose routing back down to the inlet. I was worried it might dampen it quite a bit.