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OK, Zach.
Yeah, it does #1, which is the entire point of doing the mod.
So that is not "in addition" to anything.
If it didn't do that, it would function just like the OEM does, i.e., default to OFF.
Reversing the action of the PSE switch is all the mod does, where ON is default and OFF can be selected.
That's one thing in my book, not two.
Now to #2:
I have a 997 GTS with PSE.
The PSE valves DO NOT automatically close at any given speed.
They are open when the PSE switch is ON (illuminated) from start (if selected with the key turned to ACC prior to cranking) to shutdown, at every speed, at every RPM.
They have nevert closed un-commanded on me, ever. (26K miles)
Where did you get that factoid?
Never read it anywhere but from you, on this thread.
I am on here to learn, but am certain that is not true- at least with my car, it is not.
OK, Zach.
Yeah, it does #1, which is the entire point of doing the mod.
So that is not "in addition" to anything.
If it didn't do that, it would function just like the OEM does, i.e., default to OFF. Reversing the action of the PSE switch is all the mod does, where ON is default and OFF can be selected.
That's one thing in my book, not two.
Now to #2:
I have a 997 GTS with PSE. The PSE valves DO NOT automatically close at any given speed. They are open when the PSE switch is ON (illuminated) from start (if selected with the key turned to ACC prior to cranking) to shutdown, at every speed, at every RPM. They have nevert closed un-commanded on me, ever. (26K miles)
Same exact history here. Have to admit to not getting the great benefit of having PSE ON as default rather than OFF. Just a matter of pushing a button to select the mode you want. For me, the default off is just fine since I like to depart the neighborhood as discreetly as possible and coming back the same way by the one second push of a button.
OK, Zach.
Yeah, it does #1, which is the entire point of doing the mod.
So that is not "in addition" to anything.
If it didn't do that, it would function just like the OEM does, i.e., default to OFF.
Reversing the action of the PSE switch is all the mod does, where ON is default and OFF can be selected.
That's one thing in my book, not two.
Now to #2:
I have a 997 GTS with PSE.
The PSE valves DO NOT automatically close at any given speed.
They are open when the PSE switch is ON (illuminated) from start (if selected with the key turned to ACC prior to cranking) to shutdown, at every speed, at every RPM.
They have nevert closed un-commanded on me, ever. (26K miles)
Where did you get that factoid?
Never read it anywhere but from you, on this thread.
I am on here to learn, but am certain that is not true- at least with my car, it is not.
The automatic closing does happen and it's throttle position and r dependent, not speed related. My earlier post explains why it's designed this way.
Pete is correct. My understanding is that even with PSE "on" (valves open), the valves actually don't open until over 3,000 RPM. When they are off (PSE disabled), the valves will still open over 4,000 RPM to optimize performance. The feature is there to minimize exhaust noise when you are at low speed/RPM. Turning PSE on just lowers the threshold on when the valves open. The only way you can keep the valves always open is to disable the solenoid in the engine bay, or install the solution discussed in this thread. I can't recall where I read about PSE functionality. Maybe it was from Pete himself!!
Originally Posted by Petza914
The automatic closing does happen and it's throttle position and r dependent, not speed related. My earlier post explains why it's designed this way.
Thanks for the information.
I have not heard any auto opening/closing of the PSE valves on my car. Ever.
Is there a source document that explains what you describe?
P.S. Why is the start up exhaust note louder (and angrier) with PSE ON vs OFF?
Exhaust sound at idle is louder- and it is louder at every speed below 3000 rpm.
That explanation just doesn't jive with my first hand experience.
Last edited by Liste-Renn; 02-08-2022 at 03:30 PM.
I found when I had PSE installed, that a simple on/off switch in the ash tray works fine for me, wired directly to the fuse box and solenoid.
had it on my 06S and my 09S. Sorry, obviously not for purists!
The other way I have seen this done (I think on 911uk forum) is to buy the alternate VW solenoid, which has a third exit pipe.
You then swap over the actuator pipes so that the vacuum is on (or off, I can’t remember which way round it is) when you start the car, and the PSE switch changes the vacuum to turn the noise down rather than up.
I bought the piece but have not fitted it because I simply disconnected it whilst in the noisy mode. It means it doesn’t go all quiet and polite at 30-50mph.
I cannot remember where I saw it but this seemed to me to be the simplest way by far.
The automatic closing does happen and it's throttle position and r dependent, not speed related. My earlier post explains why it's designed this way.
You are correct, the DME override is throttle position and RPM dependent, in the speed range I mentioned. At speeds slower or faster than that speed range, there is no override. The first qualifier is car speed, then RPM (i.e., at higher RPMs it is always open), then throttle position.
Great question. I wondered the same. It seems the valves are open while idling but will close as soon as you drive off, and then will open again above 3K RPM. Try it next time you are in your car. I noticed the exhaust noise quiets as soon as I drove away when PSE was on and thought it was odd and not working properly. I will try and find the thread where this functionality was discussed. It happened when I had my .1 C2S.
Originally Posted by Liste-Renn
Thanks for the information.
I have not heard any auto opening/closing of the PSE valves on my car. Ever.
Is there a source document that explains what you describe?
P.S. Why is the start up exhaust note louder (and angrier) with PSE ON vs OFF?
Exhaust sound at idle is louder- and it is louder at every speed below 3000 rpm.
That explanation just doesn't jive with my first hand experience.
You can do a test by accelerating slowly and staying in one gear. The exhaust will be quiet as you pull away until you get to about 3,000 rpm, then watch the light on the PSE button. When the light is on, the exhaust is in quiet mode and when the light goes off the valves are open/opening. You should see the light go from on to off around 3k rpm and hear a change in time, then you'll hear another change in time while the light is still off as you enter the range for the variocsm plus that's causing the cams to run on the other lobes where both lift and duration are higher.
Putting the PSE in quiet mode has the valves closed all the time and the light stays on. Pushing the button to put it in sport mode tornsnoff the light, but the light will now reflect what position the valves are in as the DME opens and closes them.
Can we agree that the PSE exhaust with the valves closed is essentially like the stock exhaust - quieter with more back-pressue and less flow, and the PSE exhaust with the valves open is essentially like a less restrictive higher flowing aftermarket exhaust?
If so, here's a Dyno graph that shows what I'm talking about in that the torque curve of the higher back-pressure exhaust at the lower RPMs shows more torque and then once higher RPMs are reached, the less restrictive muffler makes more torque, so the PSE system automatically close in the valves at low rpm improves the torque curve and then opening them at higher RPMs again improves the torque curve, so it's like taking the higher sections for both torque curves. The slight loss of HP with the valves closed doesn't really matter because below 3,000 rpm you don't need power, you need torque and once the valves open at the higher RPMs, both HP and Torque are better.
Chart is from Fabspeed for a normally aspirated C2S.
02-07-2022, 11:41 PM
