Mr Helmholz - simple model

[Greg Hermann]

>If this opens a whole new box of problems, just ignore.  But, I've noticed
>what a huge change expansion chambers have had of VE in 2 strokes, and after
>seeing the Mercedes Benz GT (Sedan, whatever they call em) with the v-6, and
>3 into 1 exhausts, and running 2 expansion chambers (one per side), I just
>wonder, how they came up with that...
>   Is it the shape of the cones or volume that makes a "E.C." work, or
>both?.
>Grumpy
>

Both. Megaphones convert velocity to static pressure pretty efficiently.

Greg