Vacuum in and of itself is created by lifting the gas pedal as the engine starts to suck.
It was originally used as free energy to assist in shifting an automatic transmission.
Why a “vacuum pump” is needed for braking is beyond me. Power brakes as well as power steering came from “positive” energy.
As I consider this, it seems that any device that is driven directly from the drive train is not a true vacuum device.
It may be that it is labeled as such, but it seems to be more complexity than needed.
Vacuum .. is created by lifting the gas pedal as the engine starts to suck.
It was originally used as free energy to assist in shifting an automatic transmission.
Why a “vacuum pump” is needed for braking is beyond me. Power brakes as well as power steering came from “positive” energy.
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Yes you get vacuum when you lift or operate at part throttle... when you are at a “track day” event you may not be off the throttle long enough to build vacuum especially with a supercharged engine. If you are “two pedaling” the car (never letting off the gas and just using the brakes to settle the chassis entering a corner) you will not have vacuum.. or to put it into a “street” scenario ,, you’re charging up a mountain road where you never let off the gas and are in a positive boost scenario...
Engine vacuum was used as a trigger to shift automatic transmissions (the vacuum modulator) but the transmissions all worked off of HYDRAULIC pressure generated internally, engine vacuum was just an indicator of throttle position and engine load. The vacuum modulator operated a hydraulic valve back in the analog control days and altered preset shift points (determined by pressure) to match engine load ,, now we use sensors for RPM , throttle position and “map” sensors and such to operate electrical actuators within the transmissions.
Vacuum is vacuum no matter if it is a engine pumping against a partially closed throttle or it is a vane type air pump run off of a cam chain..