Sid my bad, I was not paying atten. Good job.

 

It's all good.
6speed is a great forum to share passion, info and research with like minded Porsche nuts!

Since you got most of the PSE info already, here's some more on the stock exhaust.

Cheers.

 

Nice, wonder is there a way to keep the value flaps open on the stock exhaust

 

Yes, my dealer told me it was VERY easy... didn't ask how though.
But from what I've read it's either done by tie-wraps or by removing the vacuum lines and blocking them.

That said it still won't sound the same as the PSE because most pipe diameters with the PSE are slightly larger (specifically the ones with the valves), resonance chambers are smaller (higher compression) and the X-pipe design creates a very unique self-enforcing high-flow frequency pattern.

That said, as soon as I get my C4S I'm having a set of extra valves added right after the headers which will actuated by a button under the designation... WTF!

 

Interpreting the diagrams it appears on the stock S system without PSE with the "flaps" closed all the exhaust goes out the side mufflers. With the flaps open most of the exhaust would go out the inside tips bypassing the side mufflers as the exhaust followed the path of least resistance. It appears the PSE works the same way but the lessor back mufflers are connected when the valves open.

I heard from an aftermarket manufacturer that reducing back pressure too much in the lower RPM's reduces power and that is why there are valves. Simply keeping them open all the time might sound good but actually rob performance. I am not sure how that logic would apply with PSE?

 

You're right, there are 2 reasons why both the S stock exhaust and the PSE have valves which open above 3500 rpm...

1st is the noise pollution regulations...
2nd back pressure...

That said when the PSE is engaged the valve does not just open above 3500 rpm... it's rather more complicated than that (Porsche loveeeeees to "over" engineer after all hehehe).
Most people think that the PSE valves open 100% when engaged but in actuality they function very much like the valves in a musical instrument and are opened and closed to varying degrees as per designers/engineers specs and take into account the dB levels, frequencies, flow dynamics (back pressure), etc.
This orchestral crescendo of rising and falling notes includes the artificially created popping, barking, snarling and barks which originated from the ignition timing specifically designed (in Sport+) to create unburned gas fumes (which then ignite) as well as the cold-air intake flow dynamics/volume and an actuated valve on the Helmholtz resonator (see pic.).

Lets just say it's no coincidence that the 991 sounds as awesome as it does!

 

Nice to know, guess no point in messing with stock exhaust to keep the values open

 

I had the PSE valves unplugged (always open) on my 997.1 never noticed a power difference. Porsche used a red plug, and conviently mounted it on top of the engine where it was easy to get at. That made me think it was designed that way.... My sense is there is a plug on the 991S also. If any one finds it let me know I,d love to try it

 

I found the fuse that controlled the exhaust flap on my non-PSE 991S and unplugged it (I don't remember the number but it also controlled the rear reverse light and engine cover). The car sounded much raspier but I noticed a significant drop in low-end torque. The sound benefit wasn't worth the loss of torque, even if I found the tube and clamped it (therefore not affecting the remaining components hooked up to the same fuse).

I was going to get an aftermarket system, but now I think I may stick to the PSE.

John

 

I read somewhere (searched but couldn't find it) that instead of replacing the entire exhaust system, one could simply purchase the PSE center muffler and exhaust tips, and install into a Non-PSE car, essentially saving some money and installation time. Does this make sense? I assume it would still need to be programmed for the console button to work.

Can anyone shed light on this? I have a 991S, non-PSE.

 

Yes, you are correct. I just had this done last week. They replace the center muffler and pipes to the tips. They then need to put in the switch and re-program the ECU. No matter how you slice it you are looking at around $3600.

I have had limited time with mine in conditions that were not optimal meaning the car is not broken in and it was 30 degrees so the P-zeros would light up at the least provocation. It was not as loud as I thought it would be and the overrun pops and crackles were also not as loud as I thought they would be.

I have no scientific evidence but I believe the S exhaust is louder then the PSE exhaust with the sport turned off. Makes sense because the S exhaust has valves that open when you get aggressive. Also the PSE when open and just cruising is not very loud. So far it I like the ability to tone it back but I am thinking I am going to consider aftermarket side mufflers.

 

I wanted just to clarify with some of you guys, the difference between the S and non-S version of the PSE and the reason the non-S is more expensive.

For an S car, if you buy the PSE Kit, the only major part you are getting is the center main muffler plus the new tips. That's it!

For a non-S car, if you buy the PSE Kit, you are getting the same as the S plus also new side mufflers.

I have a question if anybody knows or can find out.

If somebody wants to put the PSE continously ON, without the button, what is the right position of the valves that control the flaps. There is a pin on these valves and by default it seems that is all the way out. Is that the PSE ON position or it needs to be all the way in?

Thanks

 

I was wondering if somebody could post a picture of the PSE tips Vs the non-PSE tips. I am trying to understand how different they are.

Thansk much

 

I am not sure that is going to work. I think they are spring loaded closed so knowing would be easy, if not I store mine on a lift so I could tell you pretty easily.

I think the ECU may change some mapping when you have PSE on so just holding the valves open may only be part of the equation.

 

Here ya go. The PSE tips are the shiny installed ones.








Hope it helps