B8 RS5 4.2L V8 2.75-Inch Cat-Back Exhaust System

The JHM 2.75-inch performance exhaust system is engineered for the B8 RS5 4.2L V8, offering a significant transformation in sound and performance. After extensive research and development, including calculations and testing, 2.75-inch piping diameter was determined to be optimal for the 4.2L V8 engine's demands, avoiding the choking effect of smaller diameters and preserving low-end torque while enhancing top-end power. The system features a meticulously researched X-pipe design, crucial for naturally aspirated V8s, to achieve the best exhaust pulse scavenging and produce a cleaner, more refined tone. The gasket-matched flanges are larger than the stock downpipes, eliminating flow restrictions and turbulence caused by the transition from the larger stock headers to smaller stock downpipes. This ensures optimal exhaust flow for maximum performance gains. The full JHM exhaust system, including downpipes and cat-back, weighs 69lbs, making it lighter than the stock OEM system which weighs 78lbs. Installation instructions recommend installing the downpipes first, followed by the cat-back section starting from the rear of the vehicle. This product is intended for off-road use only and may not comply with emissions standards for street use.