Re: Elastic air and inertia

[Godfrey DiGiorgi <ramarren@domain.elided>]

I don't know that there is an easily seperable distinction between 
resonance effect and valve overlap... However, if you're getting 
blow-back from the exhaust side through past the carburetor bridge on 
overlap, you have one radical cam in there. Even with a very mild, 
tractor like cam (like in my Moto Guzzi 850 engine, 20/52/52/20 timing 
that's only 40 degrees of overlap), you still have a certain amount of 
standoff upwind of the jet bridge due to intake tract resonance. 

Godfrey

>BTW are you sure the "standoff" you refer to  was caused by resonance
>rather than valve overlap? it seems surprising that a wave effect could
>actually reverse the flow of air and fuel droplets back through the
>carburetor.

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