Took the plunge here as well and went for Dundon Motorsport long tube race headers. Being based in Europe I'm not at all experienced with their products, in fact I'd never heard of them before regularly checking this board. However the positive comments shine through everywhere and especially Matt's advice left me with no choice but going the Dundon route.
My 997 RS was relatively similarly equipped, having Cargraphic headers and 200 cell cats, coupled to a side muffler bypass and stock centre muffler, that sounded awesome and came with a worthwhile weight saving.
On the 991.2 I'm going one further in having the catless long tube headers, might be a bit louder than the 997 RS but given the Dundon setup is valved it seems to offer the best of both worlds. Can't wait to try it out!

Maybe some one can answer this. What are the side mufflers for???

Is they anything negatively impacted by removing them like so many do??

I ask this because back in 2014; Porsche invited most of the .1 14 Owners to their new Center that had just opened in Atlanta as sort as a courtesy thing for hanging in their while the engines were being replaced. In one of the seminars, they had a GT3 up on a lift and they were reviewing and discussing a bunch of the components of the GT3. I had asked about the putting on a rear bypass and that did not seem to matter much but when mentioned about taking off the side mufflers the guy looked at us like we were nuts. He was trying to explain why they were important but it kind of went over my head

Shipping on the 7th! Thanks Ducktail!

Short answer is they're there for Euro sound limits at idle and cruise. Nothing detrimental to their removal except more of the expansion happens in the center muffler. This puts stress on the center and if you track a lot can lead to cracking of the center muffler. The design is the same as the 997 GT3's that failed often...

If valved side deletes are used, no drone is added.

The weight savings and removal of heat, for some, is more important...

Jamie

Looks great!

https://cimg9.ibsrv.net/gimg/rennlis...937bac1df.jpeg

On my RS

Jamie,

I'm in line for a new .2 GT3 in spring. It will be my daily driver while also planning on taking it to the track quite a bit, some of those track days will be at Laguna. I get that most people want a louder exhaust, but due to work, neighbors and Laguna I actually am in the camp of needing a quiet exhaust. I can opt for the GPS based valve solution, but am also keenly interested in your Orange exhaust.

What complete exhaust setup would you recommend when the goal is to get the best track results while passing sound at Laguna and staying California legal? Orange plus side bypass? Please quantify the gains (weight, hp, heat mgmt, etc.) you get from each component a bit more. For example, don't fully understand the heat removal comment you made.

Hi Dutch.

There are a few things in play here let me see if I can pull them apart.

1. Passing Sound

The Orange will definitely help you pass sound at Laguna. We've tested on 2 997's with and without side deletes and 2 991 GT3's one with side deletes that was blowing a 104db and one with stock side mufflers. All of them passed sound with or without the side mufflers.

http://www.dundonmotorsports.com/por...center-muffler

2. Reducing Weight.

The side mufflers are one of the heaviest and largest parts of the exhaust system on a GT3 (I believe about 30lbs but would have to go check my notes). Removing it from the car is an easy way to shed weight. Substituting Valved Side Muffler Deletes helps to reduce weight, and with the valves drone is kept in check at highway speeds (the valve switches the exhaust flow to a longer path in the center muffler to keep the drone frequencies canceled out).

Muffler and Valved side deletes as a complete kit will be available after the holidays (need to get the mufflers finished first!)

3. Removing Heat

The side mufflers also get pretty hot and that heat is close to the rear tires. To help the tires stay at a more controlled temperature, removing the side mufflers help. It also helps with engine bay temps a bit.

4. HP gains
Gaining horsepower is about getting more air into and out of the cylinders. Properly designed headers are an effective way to do this. All of the side muffler deletes and center mufflers discussed so far are all after the catalytic converter and won't make any meaningful horsepower gains. The gains come from the headers, our 200 cell street headers maximize gains while keeping catalytic converters in the system. On the 991.1 GT3 we saw gains of 30-35whp on the RS 4.0L gains were 25-30whp, we expect slightly better on the 991.2 due to the cam designs and the current torque output, but haven't been able to test one at our facility yet.

Here's a link to our 991.1/991.2 Street Headers
http://www.dundonmotorsports.com/por...catted-headers


A complete system of our Street headers and an Orange Muffler would be a potent combination for track use. Ticks all the boxes above, increased power, reduced dB level, no drone and less weight!

Jamie

Thanks for the detailed response. Makes sense.

I'll definitely keep my eye out for the complete kit. Perfect timing for when my car arrives in the spring.

I had Graham Rahal Performance bypass exhaust placed today on my GT3.2. The sound is simply amazing. I’ve only used Sharkwerks in the past, but was willing to try something different. I couldn’t be happier. Highly recommend. Looks great too. Sorry no clips yet!

Big difference?... more growl as most say, or anything else of note?