socalpcarfan

I've been unable to duplicate the crackle and burbling exhaust notes of the 991 PSE on my recently acquired 2012 997.2 C4S with PSE. Is that feature specific to the 991 model (PSE)?

nwGTS

Crackle and burble is just a rich air:fuel ratio. You can get it on our PSEs at start up before the car warms up. When your engine is cold, the gasoline is less likely to evaporate and create the correct ratio of air and vaporized fuel for combustion. Engines with electronic fuel injection have sensors that compensate for the cold by pumping more gasoline into the mixture. The engine continues to run rich in this way until it heats up to about 40 degrees Fahrenheit. Before then you'll have that nice overrun burble. But otherwise you'll need an ECU flash to keep mixtures rich. Can't get that with any aftermarket exhaust unless it also includes an ECU flash. Science.

golftime

I can't speak personally about the PSE on the 991, but I had PSE on my 996C4S and now on my 997S. The 996 PSE was more throaty, and had a deeper burble than that of my 997. My 997 PSE is audible, just not as much.

StormRune

To hear it on a 997.2, you need to use a center muffler bypass like the Sharkwerks, Fabspeed, or Billy Boat along with the PSE in the loud position or aftermarket side mufflers. The center muffler effectively kills it. I get the crackle but it is largely a lower RPM off-throttle/minimum-throttle effect or as a brief bark when shifting under hard acceleration in Sport/Sport Plus.

phaphaphooey

As others have said, you will never get the crackles on the 997 like you do on the 991. There are still some crackles and pops on the overrun in the 997 but not of the volume and nature of the 991. This is because, as others have noted, the 991 is programmed to do this specifically on the overrun. In other words, it is a little hokey. I prefer it on the 997 as it sounds like a genuine high performance engine on the overrun whereas the 991 sounds like someone lit firecrackers in the tailpipes. Of course, the 991 only does this in sport plus mode as that is when the programming dictates the crackles the most.

St8haus

I have the Fabspeed center muffler bypass installed on my 2012 997.2 GTS4...AMAZING sound with the PSE on. It sounds like a race car (kinda haha) now, but is totally mellow @ 80mph on the freeway...and I have a cab! It opened up the exhaust with retaining the stock functionality (although I drive in PSE 98% of the time anyways). Great product!

The only way to get the burble on a 991 is a GTS model or GTX/X...the 2015 GTS MT has an amazing burble to it, as does the GT3 when down-shifting during spirited driving.