3.3TT Interesting wastegate? noise

[AdrianG]

Forgive me, as I'm not totally aware of where the sound is likely coming from. Anyhow, just experienced a strange noise after sharply letting off the throttle, instead of the typical "psshh" noise, it was more of a whistle, possibly with a subtle flutter.
This video (not mine) has a perfect example of this noise, at about 10 seconds.
Any ideas?

 

[Reldas]

do you get a psshh noise at all now? i literally have the same problem today. No BOV psssh noise but now i have a slight flutter when letting off acceleration

 

[AdrianG]

I'm going to take the Stinger out later today to see if it's still doing it. I feel like I remember it doing this once before quite some time ago and I attributed it to one thing or another, hadn't happened again until yesterday.

 

[AdrianG]

It did it maybe once or twice after driving it again today, then has seemed to stop pretty much entirely from what I can tell. I'm thinking it is the factory bypass valves. Maybe I'm just trying to push too much through the factory system? Maybe it is normal, somehow?
Any input is appreciated.

 

[D.J.]

I would try to capture a video of your car - making the sound.... then perhaps users can chime in.

 

[AdrianG]

I would try to capture a video of your car - making the sound.... then perhaps users can chime in.

The video I included is a very good example of the sound. The audio isn't the best, but it will certainly do.

 

[D.J.]

The video I included is a very good example of the sound. The audio isn't the best, but it will certainly do.

That's a standard BOV sound.

Inspect your diverter valves closely. What intakes are you running?

 

[AdrianG]

That's a standard BOV sound.

Inspect your diverter valves closely. What intakes are you running?

Definitely not common on my particular car, so it's safe to say it is quite abnormal, albeit maybe not "bad" per se.
AEM intakes, had them on for probably 25k miles or so.

 

[D.J.]

Definitely not common on my particular car, so it's safe to say it is quite abnormal, albeit maybe not "bad" per se.
AEM intakes, had them on for probably 25k miles or so.

hearing the diverter valve through aftermarket intakes - is like 80% of the reason many people install aftermarket intakes.

if something sounds "different" or abnormal, when you slam the throttle plate closed after building boost... that's semi concerning. What is causing the difference in sound.

is it possible the diverter valves are not working correctly and not opening, which would cause compressor surge (flutter)?

 

[AdrianG]

if something sounds "different" or abnormal, when you slam the throttle plate closed after building boost... that's semi concerning. What is causing the difference in sound.

is it possible the diverter valves are not working correctly and not opening, which would cause compressor surge (flutter)?

Right. My thoughts exactly.
Something unusual is causing the change in sound, and it is simply abnormal, at best. If I need to switch to some aftermarket BOVs, I will, but I'm not sure what the actual problem is. It makes the most sense that it is the factory bypass valves.

 

[D.J.]

Right. My thoughts exactly.
Something unusual is causing the change in sound, and it is simply abnormal, at best. If I need to switch to some aftermarket BOVs, I will, but I'm not sure what the actual problem is. It makes the most sense that it is the factory bypass valves.

I have read about other users, where the vacuum line to the diverter valve got knocked off/disconnected, causing the diverter valve to not function.

 

[AdrianG]

I have read about other users, where the vacuum line to the diverter valve got knocked off/disconnected, causing the diverter valve to not function.

The thing is, is that it stopped making that sound and went back to normal after driving it the next day.

 

[D.J.]

The thing is, is that it stopped making that sound and went back to normal after driving it the next day.

problem solved .....

 

[AdrianG]

problem solved .....

LoL. The main problem is that I don't know what it was.

 

[Rodtheviking]

Wastegate valve flutter. I would guess your BOV control solenoid is going out, not holding/regulating pressure? Also could be the ECU/tune telling the wastegate to open and close rapidly to maintain a set boost level for the conditions you were at.

 

[AdrianG]

Wastegate valve flutter. I would guess your BOV control solenoid is going out, not holding/regulating pressure? Also could be the ECU/tune telling the wastegate to open and close rapidly to maintain a set boost level for the conditions you were at.

The boost has been pretty normal. The second possibility you mentioned is an interesting idea.
Stock BOVs, maybe some aftermarkets are in order.