Whistling flex pipe. Was "CGT downpipe/cat joint, need flex?"

[Dave Hord]

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He showed me a braided flex joint, said it was a $70 part, and told me he w=
as going to give it to me for free because he was upset that his shop did t=
hat.

So, they put it in and it can flex there.

But now there's a new problem.  The stupid thing whistles like a supercharg=
er or noisy turbo.  It has a sound that is almost like the pea shooter exha=
ust of an old Beetle.  It's mostly under load, but it's definitely new, and=
 annoying.

After trying to weld up leaks and the noise persisting, they concluded the =
flex joint was a bad one.  However, that was their last one in that size, s=
o I'm to go bad yet another Friday (tomorrow) to have a different one put i=
n=2E  What an ordeal.  It's typical.  But if it is quiet after this, then I=
'll be happy.
------------

Ken and group,

It doesn't sound to me that the particular flex you have had put on your car is
defective. It's certainly possible, but more likely a design issue.

What is sounds like is that the flex pipe you purchased is of a fairly standard
design: Corrugated flex pipe with a braided steel outer liner. Most likely the
entire flex is stainless steel.  The whistling that you are getting is due to
the inner corrugations of the flex pipe.  The company I work for discovered
this a number of years ago, and worked to develop a special automotive flex
pipe that has an inner braid liner as well.  The inner braid liner smoothes out
the gas flow and keeps it from whistling on the corrugations.

Check the flex they put in on Friday before it goes in.  If it has an inner
braid liner, it shouldn't whistle. If it doesn't have the inner braid liner,
and it _does_ whistle...you'll need to get a flex pipe of a different design.

Email me off list and I can help you out.

-Dave
-------------------------------
David Hord
Marketing/Product Development
& Technical Support
Vibrant Performance
Ph:  (905) 564-2808  ext. 277
Fax: (905) 564-8653
dhord at vibrantpower.com
www.vibrantperformance.com