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Homemade PSE version 1.0 done, behold the "Evan Sport Exhaust"

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Yes, I know I'm crazy. At least my wife thinks so. Over the last months I've been trying to figure out how to make my own PSE with valves and a switch, which I have (mostly) successfully done:



I started with a donor muffler from a 2000 S, purchased from a forum member. First it needed some polishing of course. I sourced the vacuum valves from Capristo in Germany.




The plan was to do a partial muffler bypass (think Pedro or Fister) but pipe the bypass into the outer chambers of the muffler like the PSE, and with valved control. While this ended up being very tidy, in hindsight I should have run the bypass to the tips for more sound. Version 2.0 will do this, also internally so it will retain the tidy look (and hopefully pass EU inspections.) Since I can weld, I could build it any way I wanted to, but my box lives at my second house... so I had to configure the piping without access to the car, fly down there, and hope it would fit!




The finished work:



On to the wiring. Unlike the stock PSE from the factory, I am not interested in letting the ECU decide when to close or open my exhaust valves. I wanted a dash switch, where I get to pick when the beast is on or off. Since OEM dash switches are momentary, there needs to be a way for the circuit to stay activated or be deactivated with just a pulse from the switch. Solution: a latching relay. This great invention will allow a circuit to remain energized or be disconnected when triggered by a 12 volt pulse. Push the dash switch, the relay gets a quick pulse of 12V, and turns the circuit on (or off). In my case, I have the relay switching ground, since I needed a switched ground to turn on the LED on the switch when the circuit is active.

When active, the circuit switches a vacuum solenoid valve in the engine compartment to start or stop the pull of vacuum to the exhaust valves. These valves default to open (i.e. sport mode) so I set up my vacuum connections such that the solenoid valve is off when the exhaust is in quiet mode. My thinking here was that I didn't see the point in having a solenoid switched on, getting hot and using energy on long highway drives in quiet mode. This meant getting a solenoid valve that has both normally open and normally closed connections, which was a bit of a pain. Carnewal sells a complete kit including a valve that is normally closed, and this would have worked too. I just wanted to do it my own way, as usual, so I bought the kit and sourced my own valve:


Here is the wiring diagram as I set it up:


Here is the relay connected up. Blue wire is +12V from a fuse tap, and from a switched supply. Brown is from constant ground. Red and orange in the harness are 12V that supply the PSE switch and solenoid valve respectively. Yellow is the 12V pulse from the PSE switch. Black and purple are the switched ground that activate the LED on the switch and the solenoid valve itself. It was important to me that this circuit shut off with the key to avoid battery drain, though it "remembers" the last setting. If you shut off the car in sport mode, it is still in sport mode when you start it next time, since the relay is mechanical and not electronic:


Backside of the switches, I took this opportunity to add the Targa sun shadeswitch too, for my garage door opener.


I ran the wiring under the center console and up into the engine bay along with the shift linkage:


Then there were the vacuum connections. I don't have so many pictures of this part, but here you have the overview of what needed to be connected:


Here are some closeups of the exhaust on the car:



Lucky me, I have the world's coolest indi shop, TallerBox in Cartagena, Spain. I rented a bay for the day with a lift and tools, and had a blast doing all the work myself!


A rough list of parts:

-used OEM muffler
-exhaust valves from Capristo
-PSE connection kit and dash switches from Carnewal in Belgium
-Durite latching relay from the UK
-Pierburg vacuum solenoid valve from eBay UK
-random wiring, fuse tap, etc
-a ton of work and fun (priceless)

All told, I think I spent a bit over $1000 on everything, not including my time and welding consumables.

And of course… I had to record some sound clips. The verdict: not enough cowbell. Everything functions perfectly, the valves open and shut as they should, the electronics function just as designed. However, I was really hoping for a more dramatic difference in sound, so in version 2.0 I'll ensure more flow on the bypass side, plus pipe the bypass directly to the outlets. Back to the welding bench I go!

I hope this is helpful to anyone else thinking about such a mod… I'll be happy to answer questions. Just don't ask me if it drones, its an OEM muffler so, no. :-)



Edited by evan9eleven
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  • 4 months later...

A bit late mayby, but if your gonna do Pse 2.0 go from chamber nr 2 instead from chamber nr1.

The original Pse goes from nr 2 :)


Muffler cut open




Porsche Pse




My project stopped for various reasons, mayby this year :)

Edited by smygolf
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  • 4 years later...

I know this is an old post but I agree with smygolf.

The bypass should have gone between chamber 1 and 2.


The only change that I can imagine would be in the acoustic tone.

I admit... it LOOKS nice... but... I don't see anything being bypassed.


I am interested in how you cleaned the exhaust up.  SLICK!


Edited by rprieto
added text
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