Anyone Know What The Minimum & Maximum Vacuum Pressure is From a Slant6 ?

slantsixdan said
What the eff‽ Y'mean an OE pushbutton selector like this, this, this, this, this?

There is nothing such as "maximum vacuum pressure". Pressure and vacuum are opposite; we say "pressure" to mean above atmospheric pressure, and "vacuum" to mean below atmospheric pressure. Also, the question doesn't make sense in context of what you are trying to accomplish. A running engine—Slant-6 or other—creates plenty of manifold vacuum at idle (around 20" at sea level) and cruise conditions, less vacuum under acceleration, and zero vacuum at WFO (wide-open throttle). A vacuum reservoir with check valve—like this, this, this, this is used to store vacuum so the HVAC modes can still be shifted even with the accelerator on the floor on the way up a mountain.

The mode selector doesn't send out a specific or calibrated amount of vacuum to active ports, it will either connect them to vacuum or not, depending on which button is pushed.

I got a total kick out of your reply "schoolin' me" about misuse of pressure (e.g. negative pressure) vs vacuum. It is exactly what my engineering friend helping with this would say as well to me as well ... along with a diatribe about the intricate details surrounding it that would lose me in the first sentence. As a mere mortal outside the engineering world, the concept of negative pressure seems logical, but hey, what do I know?!!!

Thanks for the info you provided. I got it in my friend's hands last night to assess against the design he has us pursuing to make sure we understand all the factors and don't go down a rabbit hole with my wallet. I might be coming back to you if we get jam figuring this thing out ... thanks again !