A system for treating exhaust gas from an engine is disclosed. The system may include a housing with a first longitudinal axis, an inlet port, and an outlet port. The housing may define a first flow path. A fluid treatment element may be arranged in the flow path. The system may also include a conduit defining a second longitudinal axis and forming a second flow path. The conduit may have first and second tubular portions generally aligned with the second longitudinal axis. The first tubular portion may have a first cross-section, and the second tubular portion may have a second cross-section. An inner diameter of the second cross-section may be less than an inner diameter of the first cross-section. The centerpoint of the first inner diameter may be offset from the centerpoint of the second inner diameter in a direction generally parallel to the first longitudinal axis.