Exhaust scraping noise on decel

[jwahl16]

I have a ebay 3" turbo back exhaust, and sometimes use the silencer. But recently i've noticed when I have the silencer in an awful scraping noise comes from the lower downpipe area of the exhaust. This DOES NOT occur when i have the silencer remove, so i assume it is backpressure related. At first i thought this was an exhaust leak i had but, I just fixed it and the noise is still there. The only thing i could think of was if the flex section of the downpipe collapsed on me. Unffortunately, i couldn't find a flashlight to look up there . O i almost forgot, the noise occurs in neutral and drive (havn't tried reverse) on deceleration between 2.5-3k rpms. As far as i could tell it did not occur as accelerate.

What do you guys think? My mods are up to date btw.

 

[ajpm26]

How long have you had the exhaust for? Hard to determine without driving it or seeing it, but definitely check if the flex section rusted.

 

[jwahl16]

I have had it for maybe a year, but its only has like 1000 miles if that

 

[jwahl16]

ok I finally got around to pulling the downpipe. I shined a flashlight into it and everything looked normal. The Flex pipe was at the normal circumference. I only got it half back on (damn this heat and bugs!) so I'll try and get a video of the noise tomorrow. In the mean time does anyone have any other ideas? I'm lost on this one.

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Ok i got everything put back together and took two videos. The first one was with the engine at 130 degrees. The second, was fully warm at 180 degrees. I was pleasantly surprised, the sound was a lot more subdued then it used to be a couple months ago (the last time i used the silencer). In the first video if you turn your volume all the way up you can kind of hear it, in the second video it is almost none existent.

MVI_0684.mp4 video by snowj16 - Photobucket


MVI_0685.mp4 video by snowj16 - Photobucket