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    PSE ISSUE !!! This can be serious

    ok so i had a talk with the technical director for Greece and considering the mod he told me that:


    inside the exchaust there are 2 small flaps(i dont know if this is the correct word) that when you do the modification for the PSE to be all the time on, the flaps are really left free without control pressure..


    This CAN cause after some time, ITS NOT CERTAIN THAT IT WILL CAUSE, a malfunction in the flaps, and after some time there might be a sound from the inside of the exhaust coming from the flaps.


    this will result it a continuous annoying sound that it will not be repairable so you will have to replace the PSE.


    the free release of the flaps due to the disconection of the PSE, will make the flaps go like nuts producing a disturbing sound



    i hope i explained well, and further more i hope this is not true...

    BUT if it is???

    Re: PSE ISSUE !!! This can be serious

    umm... remove the flaps?!

    Re: PSE ISSUE !!! This can be serious

    AH AH AH....BUY another (more serious) exaust?

    Re: PSE ISSUE !!! This can be serious

    not heard of such PSE issues with 996s. unless someone can point out otherwise, i'd assume it'd be the same with the 997s.

    Re: PSE ISSUE !!! This can be serious

    Does the technical director for Greece have any kind of proof for what he told you? Sounds a little bit weird to me.
    It is my understanding that with the mod, the flaps don't move anymore at all. So how could they malfunction and start moving without the necessary pressure from the system?

    Re: PSE ISSUE !!! This can be serious

    Is this the flap you are talking about?

    Re: PSE ISSUE !!! This can be serious

    If I'm not mistaken, this is the Helmholtz Resonator, also operated using a flap. No, the flap(s) Dillinger is talking about are inside the muffler(s).

    Re: PSE ISSUE !!! This can be serious

    Hm, sounds strange but anyway. I think there is a slight difference between the mods: removing the vacuum hose or removing the connector to the hose. When removing the connector the PSE is a bit quieter (removing the vacuum hose it is louder). There is not a big difference, but to me that would indicate there is still pressure on the flaps when removing the connector and not when removing the vacuum hose. If your source is right I guess the first mod is preferred to the second.

    Also the Sport button bypass mod (which I got done on my 997) would then keep the pressure constant as the vacuum hose is still connected (and the connector as well).

    But then again, I am just speculating

    Re: PSE ISSUE !!! This can be serious

    Seriously doubt it:
    1* there have not been any issues on the 996 with the same modification, and its been around for quite a while now. Thats more proof than anything.

    2* the mod should cause the same effect on the flaps as if having the PSE on "all the time" with the dash button, the only difference is that they close between 40-80km/h. So if they don't "break" by the driver having the dash button always ON, they should't either with the mod.

    3* it is my understanding as well as RC's that the flaps don't move at all with the mod, thats the point, they are alway openend. If anything the letting the flaps open and then being forced closed continuously of its "normal" operation would cause them to detiorate quicker, and it doesn't.

    4* I don't think he has enough info or first hand knowledge to make that difficult assumption... basically hust a wild guess IMO

    Re: PSE ISSUE !!! This can be serious

    Something tells me that the dude is a bit unconfortable with people modding their PSEs (for a number of reasons), and tries to limit the phenomenon...

    This is not Serious at all!

    The valve flap that your service director is talking about is the one that closes to make the exhaust go completely through the PSE muffler. When this flap is closed the muffler is in the "Quiet" position.

    The flap is moved by a vacuum actuator that makes sure the flap is in the open position by default (when there is no vacuum on the actuator) or when the actuator fails.



    The only way that the flap would start "flapping" around is if the actuator arm came off of the flap pivot ball. It is extremely unlikely that would happen in normal use. If it were to come off, then one just reaches up and snaps the arm back on the pivot ball.

    The actuator arm coming off of the flap pivot has nothing at all to do with the disconnection of the vacuum switch, which is the popular hack to keep the exhaust loud all of the time.



    Please pass this on to your Technical Director for his information. This is true for both the 996 (pictured) and the 997.

    Re: This is not Serious at all!

    WOw orient express, thanks for the detailed pics and answers! Makes a lot of sense, at least I can sleep with ease tonight

    are you sure?

    RC, Carlos, Orient Express and others,


    first, RC is right the flaps i m talkintg about are insede the mufflers, I dont know Orient express if we are talking about the same flaps,

    BUT according to this technician, when you disconect the vacuum hose,YES the flaps are always free and open


    as RC said:

    "It is my understanding that with the mod, the flaps don't move anymore at all. So how could they malfunction and start moving without the necessary pressure from the system? "

    BUT when the flaps are open and free they are not controlled by any pressure at all, thus, making them after a while goind like nuts and producing a disturbing sound.

    AND no , this is not the case as with the 996 PSE, BECAUSE, in the 996 case, we did NOT disconnect any vaccum hose but instead a small fuse. SO the 996 PSE was still operated under some king of pressure.. as the vaccum hose or some kind of it was still plugged..


    I still hope he is talking b******t but i m not convinced yet..


    RC, if you have any technical access about this matter please do some research

    We are talking about the exact same thing

    The flaps are controlled by the vacuum actuator as seen in the first picture in my earlier post.

    The hack that everyone does on the 997 is to disconnect the electrical connector on the vacuum switch that controls the actuators. This is the brown electrical connector in the second picture. This would be the same if power was removed from the vacuum switch by pulling a fuse. (however in the 997, electrical power to the vacuum switch is provided by the DME, and the power line to the switch does not have an inline fuse).

    As long as the vacuum actuator linkage is connected to the flap, the flaps are held in the "Open" position. The vacuum actuators have a spring inside of them that holds the flap open and prevents the linkage from moving freely.

    So your technician is partially right. With no vacuum at the actuator, the flaps are open (the default position), but they do not move freely because of the actuator spring.

    There is nothing to worry about with having the electrical connection to the PSE vacuum switch disconnected.

    Re: We are talking about the exact same thing

    Great posts OE!

    Re: We are talking about the exact same thing

    Quote:
    Carlos from Spain said:
    Great posts OE!



    Yes, thanks!

    Good explanation. Good photos.

    Re: We are talking about the exact same thing

    Quote:
    Orient Express

    There is nothing to worry about with having the electrical connection to the PSE vacuum switch disconnected.



    Is that then exactly the same as pulling the hose out?
    Some have said that the sound is not the same...??

    Re: We are talking about the exact same thing

    Quote:
    Gnil said:
    Quote:
    Orient Express

    There is nothing to worry about with having the electrical connection to the PSE vacuum switch disconnected.



    Is that then exactly the same as pulling the hose out?
    Some have said that the sound is not the same...??



    Good question.

    Re: We are talking about the exact same thing

    Quote:
    SoCal Alan said:
    Quote:
    Gnil said:
    Quote:
    Orient Express

    There is nothing to worry about with having the electrical connection to the PSE vacuum switch disconnected.



    Is that then exactly the same as pulling the hose out?
    Some have said that the sound is not the same...??



    Good question.



    Well, that is what I tried to explain in my post above...

    Vacuum Hose or Electrical connector?

    Which is better?

    Both do exactly the same thing, which is preventing the muffler flap actuator from moving the flap. The sound of the exhaust will be exactly the same with both solutions.

    If you choose the "disconnect the vacuum hose" route, just make sure that the supply side line is plugged so that you do not put a leak in your intake system. This can potentially trigger a CEL fault light because the system will think that it is running too lean because of the additional air going into the intake manifold. Remember that in the default mode the exhaust flap actuators are vented to the atmosphere (no vacuum) and the spring inside the actuator keeps the valve open.

    I prefer to simply disconnect the electrical connection to the vacuum switch. This keeps the integrity of the intake system safe. The only additional thing that I would do is to cover the ends of the electrical connectors to prevent contamination from accumulating on the wiring pins.

    As a side note, if there is a 997 center console faceplate that has room for an additional switch, it is not difficult at all to add the non-chrono exhaust switch and power it directly from the fuse panel to turn on and off the quiet mode of the exhaust manually.

    Re: Vacuum Hose or Electrical connector?

    Hm, I would disagree to that, but anyway... removing the hose and disconnecting the DME is not the same... one completely removes pressure from the system while the other still keeps pressure in the system. Neither is the sound the same... but that might just be my ears

    How about this explaniation?

    The only time the vacuum lines (after the vacuum switch) are active is when the exhaust is in the "quiet" mode.

    If the vacuum lines were completely removed, then the exhaust would be in its default mode (loud) all of the time. If the vacuum switch is retained, then the vacuum lines are disconnected on the output side of the switch, and the output outlet is plugged. Regardless of which side of the vacuum switch the line is disconnected, The source side of the vacuum line must be plugged.

    Try this simple test, with the car idling, pull the "Y" connector from the output side of the vacuum switch and feel the outlet on the switch for vacuum. There will be none. This is because the default position of the vacuum switch is off (not powered from the DME) or closed. And when the muffler actuators do not have vacuum, their default state is to have the flapper valve "open" in the "loud" mode.

    I hope that this is clearer.

    Re: Vacuum Hose or Electrical connector?

    Quote:
    Orient Express said:
    As a side note, if there is a 997 center console faceplate that has room for an additional switch, it is not difficult at all to add the non-chrono exhaust switch and power it directly from the fuse panel to turn on and off the quiet mode of the exhaust manually.



    This is a very good idea, I will ask my dealer if he can do this...

    Re: Vacuum Hose or Electrical connector?

    Well, try this simple test... drive around the block with only the connector (i.e. DME cut-off control) removed... then drive around the block with only the "Y"-hose removed... hear the difference? With the connector removed the sound is the same as with PSE on, but obviosly no cut-off. However, with the "Y"-hose removed it is different...

    Also, if there is no pressure in the lines when the connector is removed, then there should be no air leaking when also removing the "Y"-hose. That is not the case. There seems to be a default pressure and I don't think the flaps are fully open unless you disconnect the "Y"-hose. That would explain the difference in sound.

    Anyway, that is my subjective judgement, I might be completely wrong and after all I am just speculating about something I don't understand

    The car is still great and I would never change it for something else ...well except for the Turbo then

    Re: Vacuum Hose or Electrical connector?

    Quote:
    Also, if there is no pressure in the lines when the connector is removed, then there should be no air leaking when also removing the "Y"-hose. That is not the case. There seems to be a default pressure and I don't think the flaps are fully open unless you disconnect the "Y"-hose. That would explain the difference in sound.




    There are 2 Y connectors in the vacuum system for the 997 PSE. One is the PSE connection between the vacuum pump and the the engine/brake booster (this one has active vacuum on it) and is on the input side of the PSE vacuum switch. The other is on the output side of the vacuum switch. Make sure the one on the output side of the vacuum switch is disconnected, not the other one.

    The vacuum switch is binary not variable, so it is either on or off. The condition you describe can occur if there is some residual vacuum in the actuator side from normal operation. This would indicate that the vacuum switch dump port may be clogged. (when the vacuum switch is "off", the output side of the vacuum circuit is vented to atmosphere)

    I get the feeling that everyone reading this is getting much more of a detailed understanding of the PSE vacuum circuit then they ever wanted to know



    This information is great for trivia games however!

    For some more exciting, graphic, and in depth reading about this topic, be sure to pick up Porsche Technical Information bulletin 2 2601 911 (997) 2/05 at your local newsstand.

    Re: Vacuum Hose or Electrical connector?

    You guys lost me at "flap." Just kidding.

    Sometimes, the simplest answer is the solution. What about just removing the flap altogether? This eliminates the free movement of the flap since it's no longer there. And with PSE always on, the flap is always open anyway right?

    I have the mod done on my car so if anyone can get a definitive answer about this potential damage issue, please post your findings loudly. I would say there is a collective ton of money invested in PSEs by this forum's members!

    And the answer is:

    The definitive answer:

    No potential for any damage, no, none, nada, nyet, nr, non, apiø, nessun damage.

    Just unplug the electrical connector and be done with it.

    Re: And the answer is:

    Quote:
    Orient Express said:
    The definitive answer:

    No potential for any damage, no, none, nada, nyet, nr, non, apiø, nessun damage.

    Just unplug the electrical connector and be done with it.



    Ummm. OT, but which language is "nr" from?

    NO, NR

    It is Dutch.

    Re: NO, NR

    dont you think RC's mod is better than disconnecting the whole electrical connector?

     
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