Sometimes I can't find the answers on Google so maybe the mechanical engineers here can help me.
This is a layman describing this so please have patience.
Most carburetor engines have approximately 20 pounds of vacuum.
I am assuming the vacuum is created by the down stroke of the piston of a four stroke engine.
Barometric pressure is measured differently than vacuum.
As a layman I think pressure would be the opposite of vacuum so the measurement would be pounds of pressure as compared to pounds of vacuum. But it is not.
With barometric pressure pumping air into an engine isn't the vacuum gauge really measuring the two, barometric pressure and vacuum?
Why do I ask,
With my small blower on my engine I have vacuum until the blower is spun enough to produce boost. With boost I am producing more pressure than barometric pressure , right?
It is measured in pounds of boost.