Re: Velocity Stacks, Belts and Door Handles

["Rich Wagner" <drsavage@domain.elided>]

Michael wrote:

>IMHO, or rather, as I am reliably informed, I don't think inertia has much
>to do with it. Air movement in an engine's intake tracts, as well as gas
>movement through the exhaust, is pretty well continuous, what changes are
>the pressure waves moving up and down the intake and exhaust passages from
>atmosphere in  to atmosphere out. 

Flow through an engine is not continuous.  The cylinder, in combination
with both the intake and exhaust tracts, acts as a Helmlolz resonator. 
This is the reason that cam geometry has an effect on the power band.  It's
also the reason that engines equipped with high-lift/high-duration cams
rebreathe and go rich below a certain RPM.


Rich Wagner
Montrose, CO
'82 GTV6 Balocco

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