I saw it in a thread on here someone talking about in their manifold they are making like 1-2PSI or positive pressure? Is this some BS or is it possible? I thought maybe it flows so well n the head near the valves its negative pulling the air and in the mani its possitive then pushing it? IDFK. Hopefully that person chimes in at either this joke or something crazy. I searched with no results.

 

Nope, no crazy bs , Positive manifold pressure was acquired from a street tuning run on my personally owned car..
Equal manifold pressure is at 1038mbar.. i was reaching 1338mbar..Volumetric efficiency is generally a ratio of air mass trapped inside the cylinder when the valves close, to the volume of the cylinder under standard atmospheric conditions.

In an FI motor, the whole cylinder is pressurized, so naturally the VE rises above 100%.

In a naturally aspirated motor, well designed intake systems, exhausts, and cam profiles can cause a "natural supercharging" effect. The air flowing into the cylinder has enough velocity / momentum that it continues to cram its way in, resulting in a slightly higher than atmospheric pressure, and > 100% VE.