H22 Euro R Intake Manifold PDE Head: A Comparative Analysis

The Honda H22 engine, renowned for its performance capabilities, has various iterations. Among these, the Euro R (PDE) variant stands out. A key differentiator lies in the cylinder head design, specifically concerning the intake manifold and porting. This article delves into a comparative analysis of the H22 Euro R intake manifold and PDE head against its standard H22A counterpart.

One of the most significant distinctions of the Euro R head is its factory-ported and enlarged intake runners. These runners are meticulously gasket matched, optimizing airflow into the combustion chamber. The Euro R intake manifold is designed with corresponding runners to complement the head’s enhanced flow characteristics. This raises a crucial question: is installing a Euro R intake manifold on a standard P13 head counterproductive? Many enthusiasts have undertaken this modification, potentially unaware of the inherent mismatch between the manifold and the stock head’s intake ports.

Internally, the Euro R and standard H22A heads appear remarkably similar. Components like rocker arms and cam caps are shared between both versions. Previous claims regarding altered valve angles, for instance, from 60 to 75 degrees, seem unfounded upon closer inspection. Based on casting marks on the valve seats, the valve angles appear identical. While precise measurements weren’t taken, the similarities strongly suggest consistent valve angles.

Further examination reveals that stud, bolt, and hole placements are consistent across both heads. This uniformity extends to the exhaust side, timing belt side, and distributor side.

While numerous differences exist between a complete Euro R engine and a regular H22A, this analysis focuses solely on the cylinder heads. The intent is to address the ongoing debate surrounding the specific variations in the heads themselves. The key takeaway is the significant difference in intake runner size and porting between the Euro R (PDE) and the standard P13 head. This difference highlights the importance of matching the intake manifold to the head for optimal performance. Using a Euro R intake manifold on a stock P13 head might not yield the desired performance gains due to the mismatch in airflow characteristics.