<VV> carburetor power valve lesson

[BobHelt at aol.com]

This is for those still learning about Corvair HV carbs. 

In 1965 Chev added a high speed enrichment circuit that included a power 
valve. Chev literature says that this enrichment circuit is activated only during 
high inlet air velocities. HUH? high air velocities? Doesn't it take a vacuum 
to lift (activate) the power valve?

Well in other carburetors  MANIFOLD vacuum is used to activate the power 
valve. But the HV carburetor derives the vacuum to lift the power valve from the 
vacuum (low pressure) created at the venturi by (you guessed it) 

HIGH AIR VELOCITY

It's the venturi effect that produces the vacuum to lift the Corvairs power 
valve, not manifold vacuum.

Regards,
Bob Helt