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re : tech: noise reduction

To: vintage-race@autox.team.net, G_Ivory@beutel-can.com
Subject: re : tech: noise reduction
From: AnalogMike@aol.com
Date: Mon, 29 Nov 1999 19:44:10 EST
Gavin Ivory <G_Ivory@beutel-can.com> wrote :

>  For a bunch of different reasons, I need to lower the noise levels on a
>  vintage race 914-6. It currently runs 2 x [3-into-1] straight thrus, ending
>  with megaphones [exit diameter 3"]. Our local builder has a proven set-up:
>  he sections-in two small Flowmasters. He's dyno'd the results, and claims
>  less than 2% power loss. The question is: Does anyone know if welding-on 
two
>  Supertrapp 5" disc sets will get decent results too?? The issue is that the
>  Flowmaster set-up carries a steep total price tag, especially relative to
>  the value of the car!

I use the long stainless steel, glass packed supertrapps, with and without 
disks on the end. This is on a 210HP 2.7.
It is fairly quiet, but not quite enough for Lime Rock.
At Lime Rock I measured 94dB with a ho-made factory style 
"sport muffler" with 2 outlets sticking straight back out. I did not have
the supertrapps dB measured. When I put the supertrapps on 
my 2.4S, and removed enough disks to quiet it down, it got
a severe flat spot. So I don't think those are your answer.

Regards, mike piera  AnalogMike@aol.com  '72 911S  '73 911RS Clone

my racing pages - http://www.analogman.com/911 

~^v^~ aNaLoG.MaN ~^v^~   vintage guitar effects   www.analogman.com 

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