Exhaust flaps close once the car starts moving and do not reopen until 4k.
Stock exhaust this isn't a big deal, but with a bypass AM exhaust the quiet to LOUD transition is a bit exaggerated.
Much better deactivating the flaps so they stay open at all times IMO.

 

Interesting. I did NOT know that. So with the exhaust button deactivated, the flaps are closed all the way up until 9K? But with the button pressed, they are open at idle, but then close, but then open again at 4K-9K? That seems like such a backwards thing for Porsche to do.

 

 

I have had on 997's and 991's the GMG center delete (my 997.1RS) BBI crossover center (997.1), BBi side delete (997.2), sharky with bigger tips (997.1RS #2), BBi side delete 991.1RS.

Sharks 997.1RS center fitment was good, no rusting, great noise, raspy.
GMG's Center 997.1RS fit was good, no rusting, bass type noise.
BBi side deletes made the best sound difference to my ear on the 997.2RS Aqua that I had and they sounded great again on my 991.1RS. Much louder.

Volume goes up with each mod. How much louder do you want it?

Do you want more pops and cracks?

Do you want more gurgle?

Do you want raspier?

Do you want a Roar?

I find the side bypass pipes are the best bang for your buck. I am ok with super loud and unvalved. I like stock type noise and no extra bass. I prefer the raspier notes.

If you get into headers etc that's another can of worms. The real HP gains come by deleting cats and doing ecu work. The "header only" or "center section only" type mods do not give you 30hp. It's more like 6-12hp. In combo with aggressive ECU work you get 30+hp.

 

I can say 100% that the flaps open on my 991.2GT3 when the Sport exhaust button is pressed when idling in neutral. A distinctive change in noise is heard which is very noticeable..

 

Right? That's what I'm saying. But apparently the flaps close again as soon as you start rolling? And then don't open until 4K?

Seems weird to me. Can anybody else confirm this is what happens?

 

 

I had the bbi side deletes on my 991GT3. On the track at full load they sounded sublime. They were not valved. later on bbi put their very first protoype center muffler bypass on my 997.1 RS and that sounded really good too. But the tips (unibody) were just a little too big for my taste...like cartoonish big.

CJ's synopsis is really accurate. Lots of different components to "the perfect tone" for everyone. I was just cautioning that if you like the way that someone's exhaust sounds when you are driving behind them, be aware that the sound you hear on the inside could be vastly different. (not always but often)

I had a 991.2GTS with sport exhaust that sounded amazing on the outside...but was barely audible on the inside.

 

PSE button on: Flaps open at idle; closed until about 3250 rpm; then open until 9K rpm

 

Akrapovic have launched a new Titanium exhaust system for the 991.2GT3 which saves weight and adds power..One of the best quality exhaust on the market in terms of build..If i was fitting aftermarket its what i would fit and the noise is more of a cultured scream and not too antisocial loud..

 

991.1 GT3: with pressed Button, the flaps open in idle, close when rolling and open again above 3k rpm and full throttle. In normal mode, they are closed until 4k rpm. The button is nearly senseless.
I have my box from a german bord member. But I'm sure you can find similar things on ebay.

 

So the difference between PSE on or off, is about 1,000 RPM of flaps open? Yeah, pretty useless.

 

 

i am going to try the fabspeed side delete with valves. I think its worth the 1500 bucks to see the difference in volume. I have heard many center deletes and i cannot see an major difference to a side delete. and the side delete retains the look of factory, and drops weight. Is it really going to be that much louder than a center delete? I doubt it with the valves.