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Old 10-03-2017, 08:42 PM   #1
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Exhaust Sound Fluxuations...

Was hoping to get a lil insight or maybe find out if its common.

Anyway, I have a 01S with a complete catless exhaust. Headers, Secondary Pipes, Flex U Pipes, and a Beluga Muffler. So nothing expensive. However the exhaust has been bad ass for its low price range. It has shown a lil bit of issues, crap welding and some fiberglass being blown all over the car.

This has all stopped and it finally got stuck with a loud exhaust note. Very nice loud too. I know some of you have heard a clip I made. I can post it again. Anyway I been thinking about adding some stuff to try and quiet it down a lil bit. Well one of the flex pipes exploded from some unburnt fuel popping. I was unable to do anything about it for about a week since I been soo busy. But it finally got soo annoying being one side wasn't being muffled. So I fixed it and fired it up..... And well, its quiet as hell. I'm not complaining but I was wondering if someone knew why.... I love the way the car sounds now. It sounds sooooo nice now.

Exhaust matches the intake sound now instead of overpowering it. But I just don't know why its soo quiet now. Anyone know why this would happen? I have shoved a endoscope into each muffler to look for a possible restriction, there is non. Sucker is just really quiet now. Louder than stock, but much better tone.

So I'm unsure if there is an issue causing it to be quiet or... You tell me?

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Old 10-03-2017, 09:59 PM   #2
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First, crap welding and fiberglass being blown all over the back of the car is normal with these inexpensive cat back mufflers. Luckily, the fiberglass phase doesn't last long.

In regards to the sound, I am hard pressed to think of something you may have done during the repair of the flex section that would result in a restriction so severe that the sound would be severely muffled. I mean, its just pipe connected to pipe, so it should be fairly obvious if you did something wrong. Again, I am assuming that you either repaired or replaced the damaged flex pipe. Nothing else changed, right?

If so, then my first thought is that you got used to the unmuffled sound (which is L-O-U-D). Now that its muffled again, it may sound that much quieter because you're comparing it to what was basically an open exhaust.

Another explanation is that previously you had an exhaust leak where the flex section mates to the rigid components and that leak was causing additional sound but was (inadvertently) fixed when you replaced/repaired the damaged flex section; so now it sounds quieter because it is quieter. I had this exact situation when I didn't get one of the connections between the test pipe and the u-pipe to seal properly.
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Last edited by thstone; 10-03-2017 at 10:03 PM.
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Old 10-04-2017, 12:35 AM   #3
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Well, during the exhaust install which went over a few months as I pieced it together one at a time, I noticed something similar. Sound changes. It seems like it would get louder or quieter. But nothing like this. And while I would like to entertain that it's just in my head, idk. I remember how my car sounded. Everyone thought my car sounded like a damn race car before the damage to the flex pipe. People have claimed to hear me coming from a mile away. Now I can hardly tell the car is running... A little exaggeration but still. It's vastly quieter than it was. I even have video and sound clips I can provide tomorrow with an updated sound clip driving the same. It's quiet. Tho sounds just fantastic.

And no, I didn't do anything different. Truthfully I cut out the damaged part of the flex pipe which made it shorter by say 3 to 4in on the passenger side muffler.

Main reason I ask is because I know certain things change exhaust note. Say car running, I pull the oil cap, entire sound changes and gets deeper and louder with almost no RPM change. I just dunno if something else broke during the time I had to suffer the blown exhaust pipe.

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Originally Posted by thstone View Post
First, crap welding and fiberglass being blown all over the back of the car is normal with these inexpensive cat back mufflers. Luckily, the fiberglass phase doesn't last long.

In regards to the sound, I am hard pressed to think of something you may have done during the repair of the flex section that would result in a restriction so severe that the sound would be severely muffled. I mean, its just pipe connected to pipe, so it should be fairly obvious if you did something wrong. Again, I am assuming that you either repaired or replaced the damaged flex pipe. Nothing else changed, right?

If so, then my first thought is that you got used to the unmuffled sound (which is L-O-U-D). Now that its muffled again, it may sound that much quieter because you're comparing it to what was basically an open exhaust.

Another explanation is that previously you had an exhaust leak where the flex section mates to the rigid components and that leak was causing additional sound but was (inadvertently) fixed when you replaced/repaired the damaged flex section; so now it sounds quieter because it is quieter. I had this exact situation when I didn't get one of the connections between the test pipe and the u-pipe to seal properly.
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Old 10-04-2017, 06:14 AM   #4
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Yup, my guess is you're exhaust is now sounding how it's supposed to when all sealed up. The "getting louder or quieter" was a leak or crack that finally blew out on you.
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Old 10-04-2017, 11:30 AM   #5
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But there was no leak or crack. The cracks were brackets. Not exhaust leaks. I have 0 and had 0 exhaust leaks. The Only, and I cannot stress this enough, the only difference now, is the passenger side is about 3 to 4in shorter pipe. Same exact pipe, just removed the blown up portion.

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Yup, my guess is you're exhaust is now sounding how it's supposed to when all sealed up. The "getting louder or quieter" was a leak or crack that finally blew out on you.
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Old 10-04-2017, 11:40 AM   #6
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Listen to Porsche 986 Full Exhaust by Joshua Gray 11 #np on #SoundCloud
https://soundcloud.com/joshua-gray-11/porsche-986-full-exhaust

And now...
https://youtu.be/SyhahsDrBOU

It basically sounds stock now with a little rasp up top. 0 drone, where it had some in 6th gear at 75ish. Everyone who knows me is commenting on the car thinking I put the factory exhaust back on. But this is a full non cat exhaust. Where as before it sounded like it, now it seriously sounds stock. Had no exhaust leak before. Cannot find a leak now.

Leaks were tested by a vapor sprayer made to help assist leaks in emissions systems.

Cracks I mentioned prior weren't cracks in manifolds causing a leak, but cracks in brackets that hold the muffler to the transmission.

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