Feeds your Cummins engine cooler, denser, outside air for greater power and fuel economy. Up to 66% greater flow over stock. Extensively tested and validated. Banks Ram-Air Intake feeds your Cummins engine cooler, denser, outside air for greater power and fuel economy. Up to 66% greater flow over stock. Its performance is extensively tested and validated: in the computer, using Computational Fluid Dynamics software - on the flowbench - and later, on the vehicle. Let the others build and ship: Ram-Air's performance is proven, again and again!