For this application we have opted to do a complete redesign of the entire airbox.
The factory intake elbow reduces in size considerably from the plenum opening to the airbox. Increasing the size or smoothing the inlet elbow has been the norm for most intakes with little to no effect in power. The effect on airflow is minimal even if there is an increase in size after going through the restrictive and small area through the OEM airbox.
Our design strategy was to create an inlet tube which kept the cross sectional area of the plenum opening consistent and enlarged it. In order to accomplish this we needed to redesign the complete airbox to allow such a large tube to pass through it.
The end result is a inlet tube which is significantly larger in volume and cross sectional area which slowly increases in size as it goes to the large surface area air filter. The plenum can now take in air to it's maximum capacity as the cross sectional area remains the same and increases.
The below images show the dramatic increase in size and how much larger the opening is to the air filter in comparison to the oem intake system.