A housing structure for improving air flow to the intake manifold of an internal combustion engine is claimed. The present invention is a replacement part for a factory-installed mass air flow sensor housing and is designed to allow for larger air flow through the housing through the use of a bypass air passage or calibration tube that reduces air flow as experienced by the mass air flow sensor. The calibration tube reduces air flow across the sensor with a larger bore on its inlet and a restriction in its outlet. The calibration tube is angled to reduce back flow from the engine.