US Spec Baywindow Bus Exhaust CAT Replacement Pipe - Type 4 Engines

This straight exhaust pipe is designed to replace the original catalytic converter on US specification Volkswagen Baywindow Buses and early Type 25 / T3 models fitted with fuel-injected aircooled engines. It is a direct-fit alternative that connects the exhaust system together where the CAT would normally sit, simplifying the exhaust layout while maintaining correct alignment and flow.

On US Spec vehicles, the catalytic converter was introduced to meet emissions regulations and sits within the exhaust system between the heat exchangers and the cross over or silencer sections. This straight pipe removes that restriction, allowing exhaust gases to pass freely through a single uninterrupted section of tubing. The result is improved exhaust flow, reduced back pressure, and a simpler system with fewer components prone to failure.

This pipe is commonly used where emissions regulations do not require a catalytic converter, or when replacing a damaged, blocked, or unavailable original CAT. It is especially useful on older vehicles where the internal catalyst has collapsed or rusted, causing power loss, excessive heat, or exhaust leaks.

Manufactured as a reproduction replacement, this straight pipe is formed to match the original CAT mounting points and angles, ensuring it bolts directly into the factory exhaust system without modification. When fitted correctly, it restores proper exhaust routing and helps maintain engine efficiency and reliability.

Fitting & Additional Requirements

• Exhaust gasket sold separately and required for installation

• Designed for use with original-style exhaust components

• Intended for fuel-injected aircooled engines

• Professional fitting recommended to ensure correct sealing and alignment

Quality

• Reproduction part

• Manufactured to provide correct fit and reliable performance

Applications

• VW Baywindow Van (US Spec): 1974 – 1978

• VW Type 25 / T3 (Aircooled, Fuel Injection): 1979 – 1983