Intermittent exhaust rattle?
02-18-2009, 11:44 PM
#1
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Intermittent exhaust rattle? EDIT: Found (pics on pg. 2)
Trying to track some rattling noise from ther rear of my S2. I haven't been able to get under the car yet, which doesn't really matter as I hear it more when driving. Specifically, I hear it between 1800 and 2800 RPM, most prominently at 2000 RPM. From what I have looked at, everything around the muffler (muffler hangers, etc) is solidly hooked up. If it were a crack or bad weld, wouldn't I hear this all the time?
In case it matters, one of my POs installed a Borla exhaust.
In case it matters, one of my POs installed a Borla exhaust.
Last edited by Wipeout; 03-10-2009 at 01:40 PM. Reason: Fixed
02-18-2009, 11:59 PM
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ohh ohhh i know this one! i have the same thing!
there's another mount inbetween the cat and muffler, mine was completely off, and i cant find where it welds back on, but yeah, deffinately check the other mount.
there's another mount inbetween the cat and muffler, mine was completely off, and i cant find where it welds back on, but yeah, deffinately check the other mount.
02-19-2009, 09:45 AM
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I have the same borla exhaust. Mine is missing the same mount between the cat and the muffler body itself. Sounds good, but mine rattles at 2800/3000rpm. Im going to fab up a bracket to weld on because I just had to replace the section of pipe between the manifold and the muffler cause it cracked wide open. So, for now, I'll reinstall the stock muffler till I get the bracket fabbed and welded.
02-22-2009, 02:10 AM
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I'd think a crack would be constant noise. I can tell it's coming from the back - haven't gotten under the car still but it sounds like it's coming from the flange from the cat back to the muffler.
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02-22-2009, 12:15 PM
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My exhaust has a couple of nasty rattles. I thought they were both from broken baffles in the muffler but after replacing the muffler it only solved one rattle (muffler did have broken baffles...shaved a considerable amount of time off my quarter mile replacing it) Now I have another rattle that sounds the same as yours...intermittent and only occurs around those rpm. Mine is coming from the resonator.
03-02-2009, 11:09 PM
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Okay, the exhaust rattle was really bad today. Somewhat there on acceleration, very noisy on deceleration in the 2-3k range. I checked everything I can see down there, everything seems tight. There's a mount in front of the cat, at the flange that leads back to the muffler, and the muffler hangers themselves. Moving the exhaust system by hand, no real noise. Drive it and get it warm, will rattle/buzz like crazy from the muffler area at idle and tons while driving.
Only thing I can think of is a weld.
I wonder...my flange is one of the triangle flanges...think the exhaust from my '85 would mount up from the cat on back? I really don't want to do that, but it'd tell me if it was a weld or something that's NOT exhaust making all that noise.
The car is benched until I get this figured out, I think.
Only thing I can think of is a weld.
I wonder...my flange is one of the triangle flanges...think the exhaust from my '85 would mount up from the cat on back? I really don't want to do that, but it'd tell me if it was a weld or something that's NOT exhaust making all that noise.
The car is benched until I get this figured out, I think.
03-02-2009, 11:18 PM
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What the stereo is for.
When the car is good and cool, get under it and poke the exhaust in places. If the hangers are failing, it will be very easy to move the exhaust farther than it should move. See if you can get it to hit something solid, and then look there for evidence of contact.
Different RPMs are going to cause different responses in the physical motion of the exhaust system. It's very possible for a particular section to resonate at one RPM range and rattle only then.
When the car is good and cool, get under it and poke the exhaust in places. If the hangers are failing, it will be very easy to move the exhaust farther than it should move. See if you can get it to hit something solid, and then look there for evidence of contact.
Different RPMs are going to cause different responses in the physical motion of the exhaust system. It's very possible for a particular section to resonate at one RPM range and rattle only then.
03-02-2009, 11:30 PM
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I was poking under it tonight, really wasn't moving more than I was able to move the one on my '85.
Spencer, the sound is coming from the muffler area, NOT the cat. I stuck my head under the car with it running to confirm.
Spencer, the sound is coming from the muffler area, NOT the cat. I stuck my head under the car with it running to confirm.
03-02-2009, 11:51 PM
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Donuts seemed okay, didn't see any loose bolts on the muffler or the heat shield. I thought the shield was my problem, too.
What's got me worried is that it's most noticable when off throttle.
What's got me worried is that it's most noticable when off throttle.