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991.2 Sound Symposer delete

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Old 03-14-2022, 09:32 PM
  #16  
Rapter
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Originally Posted by D2M
I never had any issues with the way the car sounded. I love every noise this car makes. I just randomly decided to try this as I was planning to pull the rear bumper for other reasons and turned out I liked it better without the symposer. So out they came.
the rear car;et removal enhances all the sounds you love… like you I love all the sounds too!
Old 03-14-2022, 09:45 PM
  #17  
Tier1Terrier
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@Rapter & @D2M
Thank you both for this. I'm very intrigued by this. Can you describe in a little more detail how the sound changes? Are you just leaving the openings with the white firewall adapters exposed to the engine compartment so that instead of the sound coming from the air intake it's coming from the engine bay itself? Do you suppose that there's any potential unintended hazardous consequence of this up to and including excessive heat entering the cabin through those holes? Assume that you were not to leave it completely exposed (bare metal) on the interior so as to retain the factory look inside the vehicle.
Old 03-14-2022, 10:13 PM
  #18  
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Originally Posted by Tier1Terrier
@Rapter & @D2M
Thank you both for this. I'm very intrigued by this. Can you describe in a little more detail how the sound changes? Are you just leaving the openings with the white firewall adapters exposed to the engine compartment so that instead of the sound coming from the air intake it's coming from the engine bay itself? Do you suppose that there's any potential unintended hazardous consequence of this up to and including excessive heat entering the cabin through those holes? Assume that you were not to leave it completely exposed (bare metal) on the interior so as to retain the factory look inside the vehicle.
in my application my sound symposers are still connected inside the engine compartment.

the removal of foam permits/ promotes the following:
-massive increase of induction noise into the car (air flow noises)
-enhanced exhaust note
-gear box linkage noise
-awesome whoosh of air noise when changing gears (not turbo noise)
-enhanced engine noise
-drive train noises (valve,clatter and injectors)
-sounds like a race car
-sound of flowing sand ??? Lol…it’s a funny sound and I like it


it’s still winter around here so it has been really cold …don’t know yet if there is a heat issue.

since the removal of the carpet and foam is fully reversible I suggest to take 10-15 mins to remove everything and enjoy. If you don’t like put everything back.

Last edited by Rapter; 03-14-2022 at 10:17 PM.
Old 03-14-2022, 11:07 PM
  #19  
D2M
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This is something you will just have to try, It takes 10 minutes and can be reversed back in 10 minutes. I literally did this in a random parking lot on the side of the road before I did the permanent delete. Basically everything sounds equalized, no one tone is more amplified than the other ( intake, turbo, blow off, exhaust ) everything is in harmony. This is the TRUE sound of the 991.2 engine. Who knew, I had this car since new, 14k miles and never thought of this. I drive my car in sport or sport+ %100 of the time, I have yet to put 1 mile on it in normal mode so the symposers were always on and it sounded great. I just like this better, maybe because of the sudden change..

Originally Posted by Tier1Terrier
@Rapter & @D2M
Thank you both for this. I'm very intrigued by this. Can you describe in a little more detail how the sound changes? Are you just leaving the openings with the white firewall adapters exposed to the engine compartment so that instead of the sound coming from the air intake it's coming from the engine bay itself? Do you suppose that there's any potential unintended hazardous consequence of this up to and including excessive heat entering the cabin through those holes? Assume that you were not to leave it completely exposed (bare metal) on the interior so as to retain the factory look inside the vehicle.
Old 03-14-2022, 11:11 PM
  #20  
D2M
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Once you have the fans pulled out of the grommets you will see the 2 black hoses connected to the white firewall adapter. Simply squeeze the ring and pull, leave the hoses off to the side, resemble the fans and fan cover and go for a rip. You may or may not like it.



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Old 03-15-2022, 02:55 PM
  #21  
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FYI, I just did this as an experiment over lunch. I simply disconnected the hoses under the fans as indicated.

Made zero difference in sound IMHO. Maybe it's my age (mid-50's) and mild tinnitus. In Sport mode on the GTS I couldn't tell any difference in sound. With windows down pretty much the same as I can occasionally hear the turbos spool depending on road noise and acceleration.
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Old 05-01-2022, 07:12 AM
  #22  
Sarawnty
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Thanks D2M for helping me source the parts. My 991.2 T is fairly loud to begin with. Vektor headers and AOS, Soul cats and exhaust tips, BMC air filter, EVOMS diverter valves and FVD tune. Plus the T has less insulation. I always drive in Sport or Sport+. I could definitely hear a difference in sound. First, much more pronounced diverter valve noise. I would describe the change in sound to be more mechanical. It's hard to really describe so you'll have to try disconnecting the hoses first. I've now removed the black rubber plugs to get more of the mechanical noises. Not sure if I'll leave them in or out. Thanks for the idea!

Last edited by Sarawnty; 05-01-2022 at 07:48 AM.
Old 05-06-2022, 02:52 PM
  #23  
dannyk304
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Originally Posted by D2M
The symposers are vacuum activated. You will need a constant source of vacuum to keep the activated at all times. You would have to find the main vacuum line that supplies vacuum to all vacuum operated systems and tap into that line. Or just drive it in Sport+ all the time.
Hi D2M - I've been trying to learn if the symposer is indeed activated with vacuum or absence of vacuum - like PSE exhaust valves, which I understand are open until COV switches to vacuum to close them, is this right? Are you certain symposer is on/open with vacuum and not the reverse? If so, and not sure if you know but is there a way to change the COV to do the opposite? This may all seem like strange questions but I am very interested in knowing because I want to add PSE but I don't care too much about the PSE console button (sure, it would be nice to have but easily the hardest part of doing a retrofit.) However, I do want the function of opening and closing and I was thinking of connecting the PSE valves to the symposer COV thereby switching PSE on/off with the sport button. I appreciate any and all insight here.
Old 05-06-2022, 03:07 PM
  #24  
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Originally Posted by dannyk304
Hi D2M - I've been trying to learn if the symposer is indeed activated with vacuum or absence of vacuum - like PSE exhaust valves, which I understand are open until COV switches to vacuum to close them, is this right? Are you certain symposer is on/open with vacuum and not the reverse? If so, and not sure if you know but is there a way to change the COV to do the opposite? This may all seem like strange questions but I am very interested in knowing because I want to add PSE but I don't care too much about the PSE console button (sure, it would be nice to have but easily the hardest part of doing a retrofit.) However, I do want the function of opening and closing and I was thinking of connecting the PSE valves to the symposer COV thereby switching PSE on/off with the sport button. I appreciate any and all insight here.

I can verify %100 that the symposers are activated with vacuum and spring back closed when vacuum is absent.
Old 05-06-2022, 03:12 PM
  #25  
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Originally Posted by D2M
I can verify %100 that the symposers are activated with vacuum and spring back closed when vacuum is absent.
Thank you. Any idea how I may be able to reverse the COV action to do the opposite?
Old 05-08-2022, 07:52 AM
  #26  
4 Point 0
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Whats the other end connected to?

I have the TiAL tubes. Are they connected to the hole in the metal tubes?
Old 05-08-2022, 10:38 AM
  #27  
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The inlet to the symposers is mounted to the intake Y pipe from the I/C to the throttle body. They are under boost pressure hence the heavy duty delete cap needed.

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Old 05-08-2022, 04:03 PM
  #28  
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Originally Posted by D2M
The inlet to the symposers is mounted to the intake Y pipe from the I/C to the throttle body. They are under boost pressure hence the heavy duty delete cap needed.
Thanks, that’s great info. I’ll get my mechanic to rip this rubbish out.
Old 05-09-2022, 10:53 AM
  #29  
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Originally Posted by G99x.y
THANK YOU! … Every gram counts!
Absolutely. At $40 (for the two silicone caps) to lose 2-3 lbs. a much better return than Titanium lug bolts to save 1 lb.. I'm just that much closer to a sub 3,000 lb. Carrera T that my wife can still tolerate.
Old 05-10-2022, 02:23 AM
  #30  
AlexZTuned
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Originally Posted by supercroc
Absolutely. At $40 (for the two silicone caps) to lose 2-3 lbs. a much better return than Titanium lug bolts to save 1 lb.. I'm just that much closer to a sub 3,000 lb. Carrera T that my wife can still tolerate.
While I’m not endorsing $400 Ti lug nuts, at least it’s 2-3 lbs of unsprung weight vs sprung weight. Spraying half a gallon of windshield washer fluid would reduce the same amount of weight too…


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