>Date: Mon, 23 Sep 1996 13:42:37 -0400
>To: owner-mgs@triumph.cs.utah.edu
>From: Don Mathis <donmathis@lucent.com>
>Subject: Noise due to tail pipe extension
>
>My tail pipe on an MGA extends to just under my chrome over riders. The
exhaust causes my chrome over riders to become black at the bottom. To
solve this problem I went to an auto parts store and bought a chrome tail
pipe extension.
> The distance from the muffler to the end of my tail pipe is about
10". The length of the chrome extension is about 8". I fastened the
extension such that it extended past the over rider. When I started the car
I could hear a blurble, blurble, blurble. It sounded like everyone wanted
their '57 Chevy to sound like in 1961. The ID of the extension is about 2"
and the OD of the exhaust is about 1.75". I assumed that the exhaust was
sucking air in from the back of the extension and making this sound so I
sealed the back of the chrome extension with modeling clay. No Change.
Then I assumed that the extension was vibrating on the tail pipe so I packed
glass insulation in around it. No Change.
> The outer end of the extension necks down about 1/8". I assumed that
this was affecting the flow of the exhaust so I took a hack-saw and cut this
end off leaving about a 45 degree angle on the extension. No change.
> I then adjusted the extension so that the bottom of the extension was
flush with the end of the tail pipe. That is, the exhaust coming out of the
tail pipe only "sees" a small bit, perhaps a 1/4" of the extension. No Change.
> I removed the extension and the blurble, blurble went away. I guess
I'll just paint the stupid tail pipe and clean the over rider more often.
Anybody have any idea why this does what it does. The blurble, blurble was
more intermittant than regular. It certainly is curious.
>
>
Don Mathis, Ph.D.
Lucent Technologies
Norcross, Georgia
donmathis@lucent.com
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