Flex Pipes Rattling

[minman26]

This seems to be a common issue, but I can't find much discussion on here, other than the aftermarket exhaust thread. If there an easy fix for this or are the options basically aftermarket exhaust or exhaust shop to install new flex pipe sections?

[doughboy17]

Yes, that is basically it. My recommendation would be to ensure it is the flex pipes vs. something else. I have my dealership (CPO car) telling me that my 1000 rpm rattle is my mufflers/resonators just beyond the flex pipes. I hope to get to a trusted exhaust shop this weekend to get a 2nd opinion. ... ... I still think it is my flex pipes ;-)

[Nick Fury]

As mentioned, it could be your resonators. However, it could also be your flex pipes. If you replace just the flex pipes, make sure you go with double braided flex sections. Even if you're going with aftermarket downpipes, make sure the flex section is double braided. The flex wall stuff is crap and will break.

[s4matty]

I completely got rid of the viabrations on 3 different s4's by changing the flex pipes from stainless to aluminized flex's.
Sure they wont last forever but there are upfront enough to get hot enough not to rust out fast.
Could also coat in a ceramic paint after welding in to.
I used a flex that was 1in longer mesh section then the stock flex and the awe and borla.
Another problem for viabrations ive seen with certain test pipes is the hanger bracket on the passenger side is welded up to far and not after the bend on lower section of testpipe to support the downpipe weight causing the whole downpipe and exhaust to shake at certain rpm's (this was the problem on the testpipes i have now) so i made a 2nd bracket from 2.5in muffler clamp and welded a support bracket to that to bolt up to stock location on side of the transmission and tottaly fixed my viabrations at 1k and 2k rpm

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[Starman17]

The flex pipes come in several revisions. The ones my 2014 had were quite flexible, with a bellows and metal "sock" jacket making up the flex section. The new one I replaced it with had an additional tight basket weave of metal wire over the flex section, making everything much stiffer. It does not rattle. I don't think you need to do anything fancy other than get the latest oem revision.

[minman26]

So dealer says it is “front exhaust falling apart internally.” $1900. Does that analysis make sense? Didn’t think there was a
Resonator forward the flex pipes. For that price I’d just get an aftermarket with DP.

[dubgli]

My braided style flex failed in about a month.







Someone else on this s4 forum recommended these flex pipes. From observation, I can't imagine these failing anytime soon or at all.






I just got a shop to cheaply replace and So far so good.


- dubgli