The exhaust manifold found on the - Honda Prelude DOHC 4 Cylinder Engine were designed to combine the exhaust gasses from each of the cylinders quickly with a manifold that was cost effective to produce. Our 4-2- Tri-Y off-road racing headers are designed to allow the exhaust gasses to flow more freely from each cylinder and combine in a more efficient manner. Tubing has been optimized for the 2.2L engine. This creates a reduction in cylinder backpressure and improved exhaust gas velocity. These improvements free up lost horsepower and torque. An added benefit is a more performance oriented exhaust sound.