987.2 exhaust interior shots followed by modifications.

I bought a used 987.2 exhaust the other day. Tonight I sliced the big canister off the front. There’s a hard pipe that runs all the way back and turns into the big box. It’s perforated with 8 holes about 3/8 of an inch in diameter. My new version has a much larger hole in that tube. above is looking into the muffler. the velocity stack is the exit. The other pipe coming from the engine is going to the resonator and crossover. The gases work their way back through the screens to the exit. Here’s the modification I made. I’m hoping the scoop will still activate the resonator at lower gas velocities. But I guess I’ll find out soon. It gets welded back up Tuesday.

Since you went to all the other trouble for the experiment? Consider cleaning up that port, grind the leftover tab off and shape it it a little with hand files; can only aid flow; Interested in the result, good luck.

I've got a die grinder I am going to clean it all up.....These were just pics from last night while I was putting stuff away. It was getting late and and I was making WAY too much noise!!!

Best part is it’s a donor piece. I had that luxury once too, it makes a huge difference for experiments.

All smoothed out and knife edged. Pipes flared slightly.

Wow, awesome timing, as a recent 987.2 owner, I'm just now going down the various exhaust rabbit holes, as it seems like the 9A1 engine, despite being considered more powerful/reliable by many, is also on the more "quiet" side of things, and even a little more lacking of that classic Porsche flat 6 howl? Hence my search for a little more "cow-bell." 😉 Anyways, (1) For us spatially challenged, any chance you could share a couple photos zoomed out, basically showing the whole system? I don't really know what I'm looking at, so seeing where you made the cuts in relation to everything else and how the internal system of the exhaust is designed would definitely be helpful. (2) In my limited understanding, the 987.2 doesn't have secondary cats and doing any "upgrades" to the exhaust portion doesn't really free up much of a bottleneck? Or is that only partially true? I like the idea of the Carnewal DIY mods, as spending another $2-4k on a new aftermarket exhaust system might be a little premature for me. Regardless, after reading those threads, they basically said cutting into the stock exhaust wasn't really worth doing on a .2, so would maybe going to larger pipes or a performance header be a more "impactful" mod for sound/performance on the .2? Much appreciated, and thanks for sharing your project/knowledge!

Sure. I'll do a video so you can follow where you actually are and post to youtube and share a link here once I am done. There are secondary cats...but they are in the manifold. You can reach the rear part and drill it out. I haven't since it is a very permanent, expensive to reverse mod. This exhaust mod is only because I picked up a full stock system for $250 and will have my stock system to fall back on. I also could find no decent images of the system internally. I'm just flying by the seat of my pants. Trying to get more flow and little more sound. Trying to keep the resonater working at least at lower gas speeds by using that scoop.

Awesome! Thanks for that! Yeah, that all sounds great and like a solid plan. If it all works out well, I'll probably follow suit. Definitely pulling for you! Cheers!

Video of internals.

Any updates?

Unfortunately the welding is delayed. and the 4th is going to take up some time...Probably be the 12th or 13th. My welder is a certified car guy and likes the mods.

The exhaust is back and on the car!!! The modifications I made hit my goals 100%. Louder when it needs to be loud. Not much louder at lower RPM's. More "flat six" and less Modern Porsche Vacuum cleaner. Zero drone. I think I'll call this the "Bergspyder" mod. Part my last name name and part a nod to Porsche History..... I took a video last night....and it shut off just after I got out of my neighborhood.....so I need to redo that. Here is a teaser..... Cold start, idle and a quick rev.....

Here’s a selection of commute from this morning. some other noises you may hear. Desnorkled intake with BMC filter . Numeric shifter and cables. 981 base tip. Bergspyder mod drive.

Well done! I plan on doing something similar to my .1 exhaust this winter.

It won't look the same inside...but the good news is the .1 has way more interior photos you can find online. Also remember the part I cut off on a .1 contains the catyltic converter. One of the mods often done is to remove that converter matrix from that area.

How were you recording this? Was it directly on the phone? I might try doing that with my car - but it's a Boxster (so more wind noise) which has a Fisker exhaust.. (makes wonderful noises >4,000 RPM which it way too rare in NJ..)

Ran the car with the new exhaust this weekend with the balance pipe crossover slid open. I do run a piece of sheet metal bridging the forward section of the balance pipe to keep the exhasut "leak" from blowing towards the transmission. Definitely more rowdy sounding! Not obnoxious though. There is a slight drone around that mid 2500's but not that "drive you crazy ....get in your head" Drone that some of these things put off. Makes for a nice option if you wanted to have a bit more noise. Forgot to bring my good mic and recorder....

I wonder how different this is to the Carnewal GT modification . I'm guessing it must be somewhat similar. Really interesting to see the inside of the system, thanks for sharing.

No idea. I found zero info on the carnewal guts. I did see that they cut at the same place. I never saw the interior of a 2.9 exhaust until I cut mine open. I'm loving the mod.

Hi Ric and others, curious how things are going with the exhaust ? Was planning my own similar project hopefully in the near future and doing a little research and was curious if anybody new what the "bulbous" portion (photo attached) is that enters the final muffler portion? Not a fluid dynamics engineer by any means, but have a basic idea of how/why the baffled area of the final muffler section works, and was wondering if that entering "bulbous" section might also play a part in restricting/slowing down exhaust flow? If anybody knows or has seen the inside of it, please let us know. Thanks!

Photo should be below...? EDIT - Admin - Picture is there now. Please look at: https://www.planet-9.com/threads/posting-photos-in-posts-to-planet-9.253974/ so I don't have to do this. Thanks!

Is that a 987.2 exhaust ? You likely won't have that in yours. I was expecting to see YOUR photo when I cut the rounded part off and was surprised not to see anything there!! That rounded rear wall ( I will refer to it as "the baffle" ) wasn't in my exhaust . To help locate what your are seeing in my pictures I cut the round section at the weld that is in the near center of your photo. Immediately ahead of the baffle. I cut that weld with a grinder and found the exhaust pipe still holding the system together AND NO BAFFLE!!! I then used a long sawzall blade to cut the exhaust pipe. That is this picture below. You are looking forward into the rounded section of the exhasut here. The central pipe was directly connected to the pipe leading aft that then swept 90 degrees and into the muffler box proper. There was no barrier between the rounded section I cut away and the muffler box. what that central pipe connected to is this picture.... the baffle sealing the end of the round section in your photo did not exist in my muffler. All I have done here was cut the circumference of the round section and the pipe. NOTHING else was removed. That bulbous section did not exit in my exhaust. I believe that bulbous baffle at the aft end of the round section is simply a legacy of the old 987.1 system which had a ceramic catalyst installed in that section that the entire volume of the exhaust would pass through on its way out. Instead of redoing the entire case Porsche simple routed a pipe through the open space. FYI I think, but not sure, one of the big changes Carnewal made to the 987.1 was to simply remove this entire catalyst brick (and then I am guessing remove or modify that baffle). It was totally down stream of any o2 sensor so had no negative repercussions to operation. Note that the .2 equivalent to cat removal would be to remove the downstream cat from the manifold itself since it no longer was located in the muffler. Politics warning.....My guess with these unmonitored downstream cats is that without them the car would fail emissions testing in super restrictive states and this is a legacy of places like California over reaching their emissions standards and effectively imposing their will on the rest of the world. Note the pipe did have several large holes in it as it traversed the run from system entry to the first perforated baffle in the box. I simply made those holes MUCH LARGER. (Ie cut the pipe completely) and used what was left to attempt to guide the exhaust (the scoop) into the resonant chambers while allowing a straight through passage of the gas if needed. It is not any engineering just a total seat of the pants "lets give this a try" design. I expect if this is a .2 exhaust you wont find ANYTHING in the round cylinder just a straight pass through. (and nothing like your photos) I have never seen any photos before or since of the interior of the .2 exhaust besides the ones I put up. I was kind of shocked when I took it apart since it didn't look like anything I had ever seen online. So post your photos here too....Love to see what you find. And for ease of welding FIRST SCRIBE an alignment line across the can weld seam so you can put it back together correctly, grind the old weld super clean, and then just cut the old weld. My guy charged me about $150 to weld it back up around the circumfrence of the can (x2) and the metal was plenty thick to weld. Just random slicing the top open seems like it would be a mess. I am still loving the modification. The quality of the sound is what makes it...it just makes Porsche noises now. If anything, It maybe slightly too quiet, but that I think is fixed by removing the secondary cat. Or even easier sliding the center connector over.

Yes, my photo is a screenshot taken from a YouTube video from someone in the UK who attempted a "DIY Carnewal mod" on their 987.1 exhaust, and yes, I definitely noticed that the corresponding "bulbous" section didn't really exist on our 987.2 exhausts... I need to digest all this and still need to do more work/research. I appreciate your response/info. I'll be in touch and update this thread as things progress on my end. And yes, I think that is one thing I noticed about the .2 from the .1 when I was shopping for these cars, was that despite having the "more reliable" "more powerful" engine, the .2 is definitely "less porsche" when it comes to its sound. Hence why I've been looking to modify the exhaust, only to find that the prices for a "high end" aftermarket exhaust system is pretty ridiculous considering what they're selling... Cheers!

Hi Ric, do you mind sharing who did the welding work? And, they’re in Richmond, right? I live in northern Virginia, so I could make a day trip to visit them. Also, do you think they’d be open to helping modify the muffler? I could cut it apart and modify it in my garage, but that would be pretty messy.

I've reached out to my guy. This isn't his main business (powder coating is his real business) and I just knew he was an artist in Stainless steel so hit him up. I'll let you know what he says. Any miffler shop can weld these up though. And the slice and dice is not hard if you have access to a file, grinder and a hacksaw.

Did you happen to do any before after runs to see if there were any performance gains?

None. That wasn't part of my goal. I just wanted a better sound and figured while I might gain a little it would be insignificant. Certainly doesn't feel like it lost anything, but BUTT dyno is so finicky. Still loving the sound quality.