Wastegate Sound on 991.2S?

[Elcarrera]

Hey!

I tend to drive my car (991.2S PDK 21k miles) during spirited drives with the windows down to hear more exhaust sound but the other day, while going full throttle with the windows up, I noticed a loud WHOOSH from the back right hand wheel area of the car when I lifted off the throttle between 5000-6000rpm (in sport mode, no sport chrono so no sport+).

This got me intrigued so I did several 'experiments" to try to replicate the sound. Here are the required conditions for me to hear the whoosh:

1) Sport mode on (in normal mode I can hear it VERY faintly but only because I am focused on it otherwise I can deem it as unnoticeable).

2) Windows up and sunroof closed.

3)In manual mode (PDK), select 3rd gear or higher and floor it at low revs (<3500-4000rpm). Let the boost build up to 1bar then liftoff when past 5000-6000rpm (shifting up at this point or at redline does not create the whoosh). At liftoff, the boost goes instantly from 1bar to 0bar and the whoosh sound is heard (lasts a second or even less). It sounds like pumping a manual/pedal tire pump without connecting it to a tire or football.

4) PSE has no impact on it.

5) No effect on power delivery or warning lights on the dash.

I believe this is the wastegate opening which when combined with the sound symposer activation (sport mode) makes it possible to hear the waste gate blowing off. Do any of you have/do notice this sound too?

The reason I am asking is that I have never heard it before with the windows down (now I can hear it faintly between the wind, exhaust and engine noise mix with windows open because I am "looking for it") and it is getting me a bit OCD if it was there before or not

 

[Elcarrera]

Found the solution/cause for the issue and will post it here in case someone else in the future has the same issue and uses the search function.

After researching more I discovered that the 991.2S uses a recirculating/diverter valve so the sound could not be from a blowoff valve (that typical supra noise) and a wastegate is on the exhaust side so it couldn't be it either.

I started getting suspicious that the whoosh was not normal and was caused either by a leak in the bypass valve itself or a connection/clamp that got loose or a tear).

So went to my local OPC and asked them to check it out. It was indeed a loose clamp on the diverter valve. The car is now sounding great and is actually pulling more than I recalled