Mr Helmholz - simple model

[Ord Millar]

I have heard exactly the same for an H-Pipe.  Paint it, and where the paint
has blistered up is where the crossover needs to go.

-----Original Message-----
From: Todd....!! <atc347 at c-com.net>
To: diy_efi at efi332.eng.ohio-state.edu <diy_efi at efi332.eng.ohio-state.edu>
Date: Wednesday, May 19, 1999 6:20 PM
Subject: Re: Mr Helmholz - simple model


>The way I was taught to roughly but effectively 'tune' my exhaust system
>on my 4 stroke v-8's engine's is to bolt about a 2 or 3 foot pipe to the
>header collector paint it black with some spray paint (preferably BEFORE
>installing the pipe) then do a run down the strip...
>
>After runnin the car at WOT for a 1/4, there will be a point on the
>'tuning' pipe where the paint has been burned off, and a point further
>up towards the header where the paint isn't burnt at all!
>
>At the point where the paint begins being burnt is where ya cut the
>pipe.. Whalaa instantly tuned exhaust...
>
>I've never heard a technical explanation of why this works or even if it
>helps or hurts or is just a guess at the correct length of exhaust
>pipe...