demon, I'm no physicyist, but when a a diameter decreases, doesn't flow speed increse? A simple question from a guy who took High School physics a long time ago in a galaxy far far away.........
http://www.atlans.org/elements/fluids/pg11.html of course this is a stupid attempt to explain what I almost remember - and may apply only to liquids as air is more easily compressed than liquids(proven by the Beer Consumption - Flatulence/Belching/Urination studies - which incorparated input and output diameters - completed as the basis of my Phd)
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Finally, IMHO, mandrel bending
is superior to crush bending, but like so many things in life, it is (in our Contour Exhaust Example) a very steep point of diminishing return versus cost.
Mark
