c4-toy

Does anyone know why there is a center muffler and 2 side mufflers on the 991. My 993 only had 2 side mufflers tucked under the rear wells, at least thats how i remember it.
Also I notice on PSE the center muffler is split vs the standard exhaust center muffler which is 1 piece. Thx

OldGuy

The center thingy is not really a muffler, its a resonater mostly for sound. I replaced mine with the Sharkwerks bypass pipes. I dont know if he has the 991 by pass yet but I dont see why not.

Sharkwerks.com

here it is

http://www.sharkwerks.com/products.p...1&type=Exhaust

c4-toy

What did those bypass pipes do to the sound and the overall car? Agency makes an x-pipe for both 991 base and 991S

HotLap

c4, I had the Sharkwerks center muffler by-pass pass pipe on my 997.2 CS cab and loved it! It opened up the exhaust and made it sound much better (IMO), slightly more agressive, the way I would have expected it to sound coming from the factory. Was not an obnoxious sound and some told me it made the non PSE 997 sound like the PSE equipped 997. Another advantage, it saved approx. 8 lbs at the very rear overhang and didn't void warranty or mess with the cats. Took about an hour on my back in the garage to install.

OldGuy

Exactly what Hotlap said. He said it so well I can't even elaborate which says alot for me!

ScorpionT

More sound deadening. The PSE muffler removes less of the sound, but the design is fairly similar to the S (internally).

The S and PSE exhausts are valved to give two sound modes, both of which are very close.
For the base model, their X pipe wont change the sound much. On the S, its almost like running no mufflers. Ive heard a 991 with an exhaust like that, it sounds a bit unrefined. Tuned resonators/silencers are needed to get a good sound.