Then venturi effect is that when air moves through a narrowed path, it's velocity increases and pressure drops, and that pressure drop is used to achieve some function.
The Eventuri intake does not make any use of the pressure drop, so there is no venturi effect being utilized as far as I can tell…
Most of the descriptions from Eventuri is talking about reduced air flow turbulence and hence smoother air flow, but it's unclear the effect of this in the overall design versus the reduction in restriction from their use of a more permissive filter element. They don't quantify this in any way. I don't doubt there will be an HP increase, but I would like more information on what makes their design more effective.
Obviously any intake isn't going to do anything special until the car is moving, so let's imagine the car is moving. Air is being channeled into the side intake, and the moment it encounters the air filter, that's resistance. That creates pressure at the point of contact, which the air has to overcome by increasing pressure until it can force its way through the resistance to the other side. That's going to slow it down. If you look at the inside of the Eventuri filter, they're using a cone shaped contact point to direct the airflow around and through the resistance pressure point.
Air doesn't like to change direction and loses velocity quickly; anything that it hits while it's moving slows it down. Look at the typical aftermarket filter below on the left. The air is both hitting the flat end of the cone and the paper, as well as changing direction while trying to overcome the resistance of the paper. It's losing velocity by the time it makes it through the filter element.
With their setup, it's hitting that cone instead of a flat end. The venturi shape after it gets through the filter element, gives the venturi effect so the air is losing less velocity than the other type of setup, and there's apparently no other obstacle in the path of the airflow right up to the intake port on the engine. That center piece at the end of the cone is the critical element because it doesn't just stop the air when it hits it, it directs it through the filter, and then prevents backflow vacuum as the air moves past it so the air doesn't slow down.
Look at the airflow pattern up to, through and after air encounters the filter:
The airflow is focused and faster on it's way to the engine. At speed, it's a push/pull system with the engine pulling as the intake is pushing.
This system is assisting airflow into the intake port which is the only way it's going to show more power right away at lower rpms, and consistently so all the way up the range. It's not wildly varied.
I hope we get some third party speed shop videos of installation and testing soon, because this is looking pretty darned good so far.