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Rattling exhaust

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Old 05-13-2019, 07:21 AM
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congaman
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Default Rattling exhaust

Hiya

A quick question. I have a G-pipe/secondary silencer delete (great sound, by the way).

This morning my exhaust has a big rattle which sounds like a Caribbean steel pan band! It seems to be RPM-related rather than speed related. Is it likely to be the internals of the primary silencer or cat that is rattling? Has the G-pipe caused a blow through of that silencer?

Many thanks
Chris
Old 05-13-2019, 09:00 AM
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velocitylover
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It normally happens on cars with primary bypass, where a secondary muffler splits on the outside (vertical split thru welded together top and bottom half) - ask me how I know and why I have 3 spare mufflers...
To say that I would inspect your primary for sure.
Old 05-13-2019, 11:54 AM
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JasonAndreas
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Originally Posted by velocitylover
ask me how I know and why I have 3 spare mufflers...
What model year? Do you have the modified spacer rings and are you using the stronger (10.9) mounting bolts that are torqued to 35Nm that were previously 28Nm?
Old 05-13-2019, 12:38 PM
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congaman
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Thanks chaps. Unfortunately I think I have found the rattling problem. The main fan is touching the fan housing and causing the rattling. I've been told by my garage not to drive it as the tolerances are so tight - will have to get it recovered and taken there for it to be looked at. They say it might be the alternator bearing so could do damage if driven ��.

At least I know what it is!

Thanks
Chris
Old 05-13-2019, 01:34 PM
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911Jetta
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Originally Posted by velocitylover
It normally happens on cars with primary bypass, where a secondary muffler splits on the outside (vertical split thru welded together top and bottom half) - ask me how I know and why I have 3 spare mufflers...
To say that I would inspect your primary for sure.
+1

Happened to me after a track day. Sounded crazy loud on long drive home.




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