Hello forum,
I have recently installed custom exhaust that purchased from the UK. I was aware of the potential drone issues, and I am going to combat that with adding Helmholtz chambers (aka 1/4 wave resonators or side branch resonators).
but...

I have 2 questions for the forum:

1: has anyone experienced excessively loud intake noise after changing to a more free flowing exhaust?
2: has switching to a Mina style intake helped or worsened the issue?

I am hearing a distinct sound (not really supercharger whine) but after 3500 rpm or under heavy throttle and load there is a noise from the engine bay I equate to the sound of waving a corrugated pipe in the air really fast. It is honestly not a pleasant sound, not just like air sucking into the intake, but an odd, loud sound. When I was a little kid we used to have these toy corrugated snaked that were like a whistle when you waved them through the air, that's the best way I can describe it. (sorry that was all I could come up with)

I am curious if I am really flowing that much more air that I now hear the sound from the corrugated factory intake? I would not have thought that changing the back boxes would have made this distinct sound difference up front. I am hesitant to try the Mina intake or similar, because I see the factory intake already has several sound attenuating chambers built into it and it's still making this noise... maybe the corrugated part is the culprit, but I don't want to make anything worse. (Like many of you, I have a garage full of things from past cars that seemed like a good idea at the time)

 

I should also mention, the dealer recently replaced the supercharger isolator so I initially suspected an air leak somewhere, I did check for leaks all around intake, etc and couldn't find anything.

Engine running normally, no oddities other than that noise.

 

I'd pull the corrugated factory intake off and check it closely, especially around the "accordion" area - the plastic these are made of can go brittle and crack, and sometimes the split may not be immediately obvious. Also breather pipes etc.

 

Well, I finally got around to pulling and inspecting the intake this weekend and I couldn't find anything. It's still very flexible and really just like new. Checked for any other vacuum leaks and also nothing. I did notice that when the dealer replaced my s/c isolator, they gave me a whole new nose cone, which I am thankful for. (surprised they didn't mention it on any paperwork, but I'm happy to have it)
So now I'm more puzzled.

To me it sounds like a suction type of sound, but maybe I'm just mishearing it. Could be a whirling type of sound or rattle I suppose.
Whatever it is, it only comes on under heavy throttle and load, won't present itself by just revving the engine, and nothing under just moderate acceleration, it's only when it kicks down considerably.
My only changes have been the new back boxes and the replaced s/c isolator. I am hoping it's not a tensioner pulley. It seems too coincidental to happen right after the muffler change but I'm not really sure how to assess further...

Any thoughts would be appreciated.

 

Sounds like (no pun intended, honest!) the Symposer working a little louder than most.
I could never hear it on my old XFR and can't hear it on my F-Type either (yes, the V6 SC also has a Symposer).
See here for a brief explanation of what it is and how it works:

 

thanks, that's interesting. I'll need to investigate further tonight. I do not recall seeing anything like that on my engine. I do see a reference to it in the service and repair manual, but not in any diagrams.