aFe Stage-2 Si PRO DRY S Intake Systems 11-16 Ford Powerstroke - 51-81872

Part# 21-91051

When you think about cold air intakes, there are two main components to consider. First is air filtration. When comparing oiled filters to dry filters the oiled will always filter out more particulate than the dry filter will. The added oil allows the cotton fibers in the filter element to trap more particulate matter as the air passes through it. The downfall is that in dusty environments the oil filters tend to get dirty quicker than the dry filter will.

The second component to consider on a cold air intake is performance, or how much air flow it allows. From the tests that we have seen, there is no difference in air flow between an oiled filter or a dry filter, if they are both clean. However, as we stated before the oiled filter will catch more particulate and become dirty quicker than the dry filter will. As a filter becomes dirtier, its performance decreases due to excess particulate matter restricting the air flow. Therefore, a dry filter will provide more performance over a longer period of time than an oiled filter will.

For daily driven trucks we recommend oiled filters, unless the truck is driven in an extremely dusty environment. We feel that the extra filtration power added by the oil is worth sacrificing the 1 or 2 extra horsepower you might get from using a dry filter.