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Inspired by others who've hacked their exhausts (thanks especially to @pjjames512 with the sport exhaust), I tried my hand on a spare 981 exhaust I had lying around and ended up with a really nice result on my 2.7. The sound is much improved, with some nice burbling, more gunshot sound on PDK upshift, and a snappier 1-2 shift. This is at 5000-7000 ft elevation with a 2.7L, so previously the 1-2 shift at redline is just.... lame. Now it's got a bit of a kick. If I'm honest, I'd like it a bit louder, but this is so much better than stock, I'm happy for a moment
The pics below should be pretty self-explanatory. On the first side, I cut off half of the top to see what was in there, but on the second side I got smarter and cut a much smaller hole, which is all that is needed to remove that piece of pipe. This saved probably a half hour of TIG time, and easily twice that on cleaning/fitup time.
I ground down the new inlet to make the entrance as smooth as I could (it could be a lot better, but I didn't have a 90-degree die grinder). Since I was going to TIG this back up, I knew the backside had to be pretty clean, but... you can't really clean the backside very well. So although I did use TIG to put the muffler cans back together, I would recommend MIG instead, preferably with 309 flux core + gas (dual shield). Go slow and pulse it, just like how they do in the videos for the E9x M3 exhaust mod when putting the muffler can back together.
I suspect the Carnewal/Cantrell mod is less dramatic since it is less intrusive (at least on the 981, where no visible changes appear with their work). But it's just speculation.
bumping an old thread, but curious if anyone knows or has images of what carnewal / cantrell mod actually does inside a 981 muffler.
I think it would be odd for someone to know as there are no external signs of cuts/welds and unless you stuck a camera up in there... --anyone have Carnewal and a scope camera that can do that? (Speculation is a die grinder inserted in to remove a section of the pipe.)
Carenwall/Cantrell cuts off the pipe as it enters the muffler and then reaches in and cuts a hole in the pipe that runs through the muffler. The pipe from the headers is then welded back on.
Carenwall/Cantrell cuts off the pipe as it enters the muffler and then reaches in and cuts a hole in the pipe that runs through the muffler. The pipe from the headers is then welded back on.
Any idea which pipe they are cutting?
I know this is a 987, but I removed the pipe as the OP has done on his, and mine is MUCH louder and less PSE sounding (i had a 991.1S with PSE that i LOVED so just trying to chase that noise).
I know this is a 987, but I removed the pipe as the OP has done on his, and mine is MUCH louder and less PSE sounding (i had a 991.1S with PSE that i LOVED so just trying to chase that noise).
They cut the section with the red strikethroughs. This mimics what the PSE valve does. (sort of)
Last edited by thecajunboy; 12-13-2022 at 10:55 AM.
So in theory, can any reputable exhaust specialty shop be able to do the Carnewall mod? I am luck enough o be within a 2 hour drive from Cantrell in Washington, but I would obviously rather get the job done locally if possible.
So in theory, can any reputable exhaust specialty shop be able to do the Carnewall mod?
Actually, any good welding shop should be able to do the work if you show them the images posted above. I've modified several types of mufflers and exhaust systems and always used a local welder to cut and re-weld the connections and cans.
They cut the section with the red strikethroughs. This mimics what the PSE valve does. (sort of)
Thanks for sharing I always assumed it was the other end that was cut (but was probably wrong). I do understand that there is no sign of cutting/welding on the outside walls but only at the pipe inlet area, leading one to believe that a die grinder is inserted and used to cut the pipe in the area you highlighted (or at the other end =outlet).
Thanks for sharing I always assumed it was the other end that was cut (but was probably wrong). I do understand that there is no sign of cutting/welding on the outside walls but only at the pipe inlet area, leading one to believe that a die grinder is inserted and used to cut the pipe in the area you highlighted (or at the other end =outlet).
so I bought that used exhaust. Have not modified it yet. I was gonna die grind that pipe the shorter one near the center. Are we thinking I should do something different now.
I figure I will share my results with the class as well. my goal here was to mimic my old 991.1S PSE sound...which was amazing. I've owned 10+ Porsche's, and that HAD to be my favorite sounding exhaust of all time (even more than my 991 turbo with valved exhaust and headers). Every time I got in the car, I would turn on PSE. In Hein site, I probably should've never coded it and just left the valves unhooked, but I did like the idea of having a button when I wanted to be quiet lol. A while later, a buddy dropped by with a 981 GTS with the OEM PSE, and it TRUMPED my 991.1S's PSE tone...no idea how, it just did, and THAT's the tone I was after.
So! I put the car on the rack, removed the mufflers, and cut an access hole like Wulfgang did to access the connector pipe. I chopped off the middle of the pipe, assuming some exhaust would go into the chambered side and some exhaust would go to the 'exhaust tip' (or louder) side. (I also picked up some GT4 tips b/c I hate the stock look, which may change the exhaust note). After chopping the pipe off, I welded the access cover back up, and bolted everything up and fired here up, I have a few videos below to show you what it sounds like
To me, my exhaust doesn't sound as throaty as everyone else's, and has some rasp I really don't care for. I've talked with Wulfgang about this, and we think this MAY have something to do with the amount of pipe left on both ends, and he recommended I take the pipe all the way to the inside walls. I'm not 100% sure how this would affect noise, but it's something to note. I also haven't swapped my OEM tip back on to see if that changes the tone (mainly b/c it's a PITA and i feel so defeated currently lol). but I'll be sure to report back if / when I do.
My other thought for anyone who would like to try this, is potentially just cutting a 1" hole in the connector pipe (instead of cutting it all the way off, see picture below) and angle it towards the exhaust tip pipe.
2 videos of cold start and revving here below: don't mind the terrible quality, i'll get some proper ones when it's not raining outside with some driving / chase car / in car stuff here soon :
I also wonder if you left that pipe alone, but cut a hole in the 'exit' pipe to connect the chambered area to the non-chambered area how that would help. (pic for idea)
An additional option is to install butterfly valves just ahead of the muffler, add a vacuum actuator / control and get what is essentially a straight pipe exhaust when you want loud and a stock muffler when you want quiet. I did just this and it is great! Zero drone in quiet mode (which from I understand is not the case with most aftermarket mufflers) and fantastic sound when open.
12-11-2018, 11:09 PM
981 OEM exhaust hack
