Abstract: A method of retrofitting an aftertreatment system of an engine is provided. The aftertreatment system includes a diesel particulate filter. The method includes removing a regeneration routine associated with a diesel particulate filter from an electronic control module of the engine. The method includes replacing the diesel particulate filter. The replacement includes removing the diesel particulate filter from the aftertreatment system. The replacement includes providing a housing at a location of the diesel particulate filter. The replacement includes proving a first end plate at an upstream end of the housing, and a second end plate at a downstream end of the housing. The replacement includes providing a plurality of hollow tubes between the first end plate and the second end plate. The replacement includes providing a plurality of cylindrical inserts adjacent to one another within at least one of the plurality of hollow tubes.