HHR 3" MaxFlow Downpipes:
This superbly fabricated piece delivers Hahn RACE-quality CRAFTsmanship! The end result of thousands of miles of testing in numerous vehicles, we've brought you the downpipe that does it right. The metal-matrix high-flow catalytic converter is the last word in compact performance converter technology. The effect on power is minimal, typically about 5% as compared to our Off-Road downpipe that comes without the catalytic converter.
Continuous Mandrel Bends
Smooth, wrinkle-free bends for maximum flow. Our sophisticated in-house Mandrel Bending provides a clean, quality result, superior in appearance AND function to pipes formed by welding together miscellaneous chunks of tube. No unsightly welds to rust and impede flow.
Ultra-Strong Flex Section
You won't see flex section failures on Hahn downpipes. Our high-quality stainless steel flex design has evolved from years of experience and thousands of downpipes we've produced. It features an exclusive three-layer design for maximum flexibility combined with optimal durability.
Here's where we really nailed it. Our new SensorChamber creates a perfect environment for the downstream O2 sensor. Innovative design and extensive testing has proved that the SensorChamber prevents diagnostic trouble codes (DTC's), and will not set the Check Engine Light (CEL). You won't have to worry about random CEL's popping up due to the high-flow catalytic converter.
A note on 02 sensor placement...
Your car's O2 sensors are super-sensitive, and amazingly advanced little pieces of technology. Without them, we'd not be able to generate today's superb levels of fuel mileage and power. But they can't just be shoved in the exhaust anywhere! The delicate sensor element within is subject to damage if the sensor position is not inherently self-draining. As illustrated in the diagram above, the sensor must be mounted so that it can drain, in an upper position between 9 and 3 o'clock. If the sensor is installed in the pipe in a position that does not allow it to drain water condensate and particulate matter, the sensor's accuracy, and ultimately its lifespan, will be adversely affected. Non-draining O2 sensor positions between 3 and 9 o'clock are where the problems begin. Beware of amateurish pipe designs that do not take this into consideration!