DIY 987.2 PSE Muffler Modification / PSE+

Hello Planet-9 Some may remember my DIY 987.2 High Flow Cat thread: DIY 987.2 High-flow CAT upgrade While I don't know it resulted in any real HP, the sound of the car may be marginally better... With that said, I specifically sought out a 987.2 with PSE so I could have the option for loud/quiet, well, unfortunately, the loud isn't enough and the quiet is too quiet....also, I am not a fan of how the OEM PSE logic works, mainly lack of memory from restarts. As part of how to reconcile that, some research on another Porsche forum led me to find out about the "Soaristo Controller" ( Soaristo page ), unfortunately he has gone cold on his site and other p-car site, but i was able to find this on eBay, that seems to be the exact same thing... eBay PSE Controller Okay, enough with that, I had installed the controller almost as soon as I got the car, but had not make the time to finalize, which was really nothing more than running a single wire into the engine compartment. I finished that this week, tested it, works as advertised, GOOD! Onto this project...I want to document this as well as possible, hoping to have this complete this weekend or early next week. Thought process, I know the PSE sound is rather nice, why not move that "sound" over to the PSE Off position, then "spice things up" a little by make the PSE On function, a bit louder. Tuesday night after work I moved cars around, got the cayman on the lift, GTi outside....about an hour later, mufflers were off, GTI back inside and had my works space laid out for Wednesday night Got to break in my new HF tool cart Cars back inside before dinner and ready for a fresh start the next night 987.2 PSE laid out for starting point of reference (pardon my dirt floors )

I took the time to wire wheel the "suitcase" as thoroughly as possible, you can see it is a vast improvement over the other side, surprisingly clean when I wiped it down with acetone Marked out cut lines on the top of the suitcase to allow for easy welding back together With that, we reveal the inner workings of the 987.2 PSE.... My plan is to essentially "move" the perforated pipe that is currently attached to the valve portion of the exhaust over to the position of the small/quiet tube. This will be accomplished by cutting the inlet to the suitcase where the post CAT header pipe turns into a cone, remove the small pipe and replace it with a 2.25" 90° elbow attached to a straight tube with a perforated section that will then merge at the end of the muffler with the new solid pipe that will be attached to the valve side of the exhaust. I am certainly over simplifying this and under estimating the amount of work, but this is a project I've wanted to do for a while, and when you have the means to weld metal, there isnt too much that cant be repaired. I am hoping to get back out to the garage tonight, my plan is to "fixture up" this side, much like I did the headers and begin the rest of the dissection and start working on the new setup.

Got out to the garage for a little bit last night....got the muffler section "fixtured up" it is certainly crude, but holds it in place rather nicely....the suite case is screwed down with one small drywall screw to ensure it goes back in the same place, then I'll weld up that little hole when I'm done. Once that was done I cut off the section where the over axle pipe meets the suite case, then started cutting out the small/quiet pipe, by the time I got there it was dinner time, so left it alone so I could think more on how I want to continue dissecting the guts....more to come, planning to put some more work in this weekend. Inside of the over axle merge section

Was able to dedicate some time to the full deconstruction yesterday and got some solid fab work done last night. Gutted suitcase Played with a bunch of ideas for mockup, but this is where I landed Enlisted the help of a buddy that has a tubing expander, there needed to be a slip fit on the valve end (shockingly it was like that from Porsche)....This is the end that slips on the valve side of the exhaust, started as 2" OD tubing, flared it up to 2.25" on the straight pipe side and a ~2-1/8" on the slip fit side Finalizing the slip fit side Tacked up the 90° elbow to do a good test fit Next we welded on the 90° elbow Welded it all out, all that is left to do is trim and flare the 90° that will be the feed for the muffled side....we will cut that so it is protruding ~1/4" then put a flare on it just like the other side

Doing my best to keep chipping away at this project, managed to get about an hour out in the garage last night.... Flared the rear 90° to fit tight in the perforated tube as well as the end where it will meet the over axle section, got it positioned and ready to weld into the case Welded into place....wasn't easy (or pretty) but it is fully sealed, trying to avoid any strange sounds Dug out my body working hammers....tried my best to give it a nice bell shape at the end, admittedly, its not perfect, but certainly looks better in person Next it was time to start the reassembly process....frustrated at myself, I forgot to take a photo of it in the fixture....BUT, the fixture worked rather well. Knowing I cut the over axle section off with with a 0.045" cut off wheel, allowing for for a little "wiggle" I set the two parts in the fixture, used a piece of TIG filler (0.0625") thick at the top, tacked it, then worked my way around ensuring a similar gap....everything seems very consistent at this point. Going to leave it tacked like this until I have the other side complete and can test fit everything, once I verify that, I'll burn it in all the way around Hoping to get back out to the garage tonight to get the passengers side case cleaned up, fixtured up and with any luck, cut apart

Now that one side is done I wanted to put together a couple diagrams detailing exactly how the PSE system works, obviously these graphics are highlighting my revised " PSE +," however, the logic is the same on how the air would flow with the valve Open versus Closed.... see earlier photos of the OEM setup inside the suitcase Please note that the photos are from above, so it is tough to see the "top tube" that I call the "balance tube," but it is very visible in many other photos in this thread. Note - that tube has not been touch in any way from the factory; I expect it is there from the factory to act as a resonator, pulse canceller/deadener, etc. My point in highlighting this feature is I feel this is a key component in maintaining a "mild" sound, whereas many aftermarket companies that offer upgraded valved setups run out of the mufflers directly into the x-pipe. Just a theory.... Onto the photos....Here are my full axle back system layout diagrams PSE OFF Setting (valve closed) Close up of the closed flow PSE ON Setting (valve open) Close up of the open flow For Reference, here is a Soul PP axle back valved setup....looking at the angle the tube exiting the mufflers enter the x-pipe, I can certainly speculated what is going on in those mufflers....

Now that the drivers side is essentially complete, I will likely tone down the detail on finishing the passengers side. That being said, made it out to the garage last night for a little bit, got the passengers side exhaust cleaned up, fixtured up and the top of the suitcase cut open. This fixture came out a little better than the first side, holds quite well I thought this was a good reference photo to have for the inner workings of the PSE system Here are a copule shots showing both sides with the tops of the cases cut out....these should provide the perfect point of reference for stock vs modified. Hopefully this will provide a good resource in the future. The plan for tonight is to get back out to the garage, cut off the over axle section, cut out the OEM piping and finalize any cleanup needed. Its supposed to be chilly here Saturday, so my hope is to get the passengers side build, tacked and fitted, then see if I can get started on burning it all back together.

As mentioned, photos will be a little less involved....I did get out to the garage last night, got the passengers side "gutted" and all the replacement piping cut/fitted....now just a little more cleanup and time to start welding it all together. If all goes as planned, I should be doing a test fit Saturday afternoon and if the stars align, start welding it all back together. Here are all the guts from the passengers side muffler, all that I will keep is the baffle plate. Also, not surprising, complete deconstruction only took ~40min, lessons learned I guess. Spent probably another 45min-1hr getting the rest of the piping cut and fitted then cleaned up the shop. should make starting on Saturday easy, just need to cut/flare the slip fit pipe for the end of the straight pipe, then drill the hole for the merge and it will be time to start melting metal Until next time.....

Moving right along, a productive weekend was had, the project is finished up and to say I am happy with the result is an understatement! Finished up the guts of the passenger side plumbing, got the over axle section welded back on and ready for a test fit... Here are the two open mufflers side by side I wanted to make sure nothing was glaring wrong with how things were fitted. I bolted the entire exhaust back up, and installed the pipe that connects the two cases along with the x-pipe and tips, all looked good, nothing to be concerned about....so back off the came and on to the daunting task of welding it all back together I did photograph both sides, but the process was the same, try and keep gaps as close to the width of the cutoff wheel where possible, you'll see a couple of places where the case flexed enough to pull them in a little tight, this actually worked well to keep things lined up and not have to fill too much. Tacked up This was the worst gap on both sides, luckily with a MIG you can relatively easily fill gaps with a little patience and a lot of on/off tacks Far from pretty, but it will certainly do the job, I am confident with a little flap wheel and some more time it could be made to look a little bit better, but I wasn't that concerned Both sides finished up

Now for a couple of sound clips....The wifey was nice enough to help me with a couple of short revs with both PSE Off & PSE On Needless to say, I'm super excited to get out and go for a drive PSE OFF / Quiet Mode PSE ON / Loud Mode

I'm doing the same kit as you with the eBay PSE controller. Do you have pictures of the electrical installation process? Also, where did you tie in for the vacuum?

Hi @O1K , I didn't take a photos of that install, mainly followed the directions it comes with and referenced the threads over on RL RE vacuum: I didn't need to tie in anywhere, my car came with PSE, I only needed to wire up a new plug for the solenoid

Awesome work! Any chance of getting a video of with a flyby? Really difficult to judge the sound with a car sitting in the garage. I was wondering if there was a length difference between each bank's piping but it seems there is no compensation with the cylinder bank offsets... Meaning the header/manifold collector on the further front bank's side should be moved back towards the exhaust and the primaries would thus have a different shape, if the goal was equal length exhausts on both sides. This should in theory be able to provide higher pitch especially with a proper x-pipe.

Hoping to get some videos one of these days @Roksi , might be able to happen in a couple weeks when I am up at ToD for a few days.... re: piping length, I made everything as close to equal length as possible, but as you mentioned my efforts are futile in comparison to the difference in what the OEM headers have....I would certainly love to hear this muffler setup with a proper set of equal length headers.....maybe that could be a next winter project!

Been a while, still driving the car and loving the exhaust mod.... Was on my anniversary getaway with the wifey, we spent a fair amount of time up on the blue ridge parkway, so after the 2nd or 3rd tunnel she realized that I am a grown child, and started recording some tunnel music from the Cayman . Here is the best video she captured given traffic and all the variables, I have to say, at this point I'd be hard pressed to feel the need to buy an aftermarket solution vs doing this again

Just imagine how great that would sound in a Boxster ..

Felicitaciones!!!! Excelente trabajo 👍 Nivel Máster!!!!! Saludos desde Chile

@fouckhest This is awesome. I'm considering doing this to my PSE because mine isn't loud enough. I want it loud, like Capristo, Armytrix, Soul, etc. Would you say this is as loud, a little quieter, similar, or what? Similar tone to anything else you've heard?

@blackharp Honestly I don't have a point of reference to compare to anything else. Also, I've not even heard my car from outside the car lol. That being said, I feel like now, my "Quiet" mode is like the OEM "Loud," the new "Loud" is certainly a good bit louder, but again, I don't have much for a point of reference. I would say that I could stand the "Loud" to be a little "Louder," but, my previous play car was a boosted VW R32 that was straight piped (at times), which I loved and still miss, but it could be obnoxious at times lol Hope that helps a little.

Few cars can match the unique sound of a straight piped VR6! Also thanks for the post and planning on opening up my exhaust as well.

Really cool exhaust documentary/journey! Love the Mk IV and I too love the sound of a wookie at full song! I've got an IS38 turbo swapped Mk7.5 alltrack for a daily.

Thanks, appreciate it, was definitely a fun project. I can imagine that alltrack is fun! The new FSI stuff is just silly, if you havent been following, HPA brought a bunch of the new VR6T engines in to do swaps into new golf Rs, those will be silly cool!

The alltrack is pretty fun, but I guess I've gone as far as I want to go with it. We'll see how long I keep it! I have been following and it's crazy! I actually live about 10 mins away from them.

Oh nice! I certainly hope one of those cars makes it to the east coast, I'd love to see one!

How is the drone with this setup in the quiet and loud setting? Great job on doing this!!

Thanks! Honestly, I couldn't say that it is any different than what it was from the factory