When designing air intake systems, engineers need to take everything into consideration, not just making sure it fits. From the size and surface area of the filter to where it is actually inducting cooler, denser air there are a lot of things to consider.
Testing on the flow bench at Banks is a complete prototype Ram-Air intake system for the 2017 to 2019 6.7-liter Ford Power Stroke. While the design for the system has been tested for flow and density increases on both the flow bench and on the road and is thus locked-in after many iterations and fine-tuning, the materials used in certain locations of the system are still under consideration. The part in question is a replacement for the tube that goes to the throttle body, and whether it will retain its shape or collapse under extreme conditions. Banks is testing identical parts in form and function, but each is made from a different material: nitrile sheet rubber (or NBR for short) and silicone.
Both materials have great resistance to cold temperatures while remaining flexible, and that flexibility is key when taking the movement of the engine and vibration into consideration. NBR has a greater flexibility at lower temperatures, but silicone is the winner at higher temps that can normally be seen under the hood. NBR is more resistant to fuels and oils, which makes it an ideal choice for any automotive application, but silicone exhibits less compression than nitrile.
One size never fits all and even though it would be easier to use something off-the-shelf, each vehicle and system’s needs are different. There’s more to consider both pro and con for each, but it’s the design and testing that makes Banks different than the rest.