M954

Hey What's up,

Does anyone have any experience with flex pipes going bad on their car? I have a 2001 A4 2.8Q at 4000rpm and over it whistles so loud it hurts your ears. I have been through 3 LLtek Mufflers and found out it could be the flex pipe. any info. would be great. Thanks.

CTA4AVANT

However....mine is from having aftermarket flex joints welded in after my OEM ones were destroyed on a speed bump in NYC (long story).

My local shop did the repairs and had i known...I would have researched this a little more.

Apparently the OEM flex joints are "smooth" inside. The aftermarket ones I had installed are "corrugated".

This corrugation creates turbulance....hence the "whistling" noise.

I have found a source (Vibrant Performance - see below) for "smooth" aftermarket flex joints and sometime in the near future will have the crappy ones replaced.

BTW - Replacing OEM w/ OEM means replacing the whole downpipe/flex joint/ catalytic converter. It's a single welded component and they run anywhere from $250 (aftermarket assembly) to $800 (OEM assembly from the Dealer).

I hope this helps.<ul><li><a href="http://vibrantperformance.com/catalog/index.php?cPath=1022_1035_1064&amp;osCsid=d96fb3de bfd7fd6ce4c9e67536c29028">Vibrant Performance</a></li></ul>

M954

Thanks for the reply, I am new at this whole computor thing. I actually read your post on this subject and I was really hoping to hear back from you since it sounds like the same problem. I didn't do any damage to the exhaust, I just put the new muffler on and like I said, three Mufflers later it still whistles. Any idea on how I can tell if it is definitely the flex pipes and which side it is.

JJMcWank

I've been looking for an aftermarket replacement and haven't seen anything cheaper that about $380.

If you know anywhere off hand that sells them please let me know!

Thanks

CTA4AVANT

Now $293.<ul><li><a href="http://replacement.autopartswarehouse.com/parts/autopartswarehouse/wizard.jsp?year=1998&amp;make=AU&amp;model=A4--003&amp;part=Catalytic%20Converter&amp;dp=true&amp ;appTransmissionType=Manual">Link</a></li></ul>

CTA4AVANT

<ul><li><a href="https://forums.audiworld.com/12v/msgs/14395.phtml">more info</a></li></ul>

M954

Thanks alot for all of your help. Looks like it's time to get this musical car singing the propper note. It is tough not being able to really put your foot in it because of a bad exaust.

petenice00

I would say we get what we pay for..293 is indeed a little too cheap..I think for OEM-quality the lowest I have seen is 400 per side.
If I read this correctly, DEC quality is questionable.

To add to this post further, I had two ECSTuning flex pipes welded on and of course had a week or two of whistling like some of you folks.

I went back to the same shop, they discovered a leak in their weld and had to redo the job (no charge of course). The whistle is virtually gone (there's a muted whistle that goes away after 4K).

The sad part is that the shop charged 3-4 hours of labor the first time. That's one new cat/downpipe assembly.

CTA4AVANT

No Problem....glad I could help. Good Luck!