HPA's 3.2L Exhaust manifold is a perfect example of engineering, combined with experience and commitment to this unique motor. Cast with a high nickel content for proper thermal dynamics, this manifold has realized HP figures of 500+ on our current turbo kits.
The divided chambers within the exhaust manifold are a critical part of our design, maintaining the integrity of the independent Oxygen Sensor readings (One O2 sensor manages two hot rear cylinders and one cool front cylinder, while the other O2 sensor manages two cool front cylinders and one hot rear cylinder). These cylinder separations allow the Oxygen Sensors to deliver the correct fuel trim offsets to the ECU.
Any exhaust manifold that places these two sensors together will jeopardize long term durability, as the hotter side of the engine will never get the right fuel balance to even out the heat placed on the valves.