More on mufflers

[david crooks <david.crooks@xxxxxxxxxxxx>]

>When one tests mufflers, can you be sure that
>the flow with hot, pulsing exhaust gas will be
>the same as a cool, steady flow of air? Or at
>least comparable from one muffler to another?

No it isn't the same, but at least it gives
you a point of reference.  The exact same
question could be asked of Cylinder head flow
testing (but rarely is!).  The question is
even more relevant with headers.  The whole
idea behind equal length tube headers is to
keep the pulses of each cylinder spread out,
and not allowing two to crowd into the same
pipe at the same time.  Static flow testing
will never show this.  It will also never show
the true difference between shorties and long
tube headers.  And what's true of the exhaust
is equally true of the intake manifold ports.

On the other hand, there is no black magic here.
Given some time and computer horsepower it can
all be simulated, although it's sometimes faster,
easier and cheaper to build it and measure!

As always, YMMV!
Cheers,


Dave