Walker 16403 Catalytic Converter with Integrated Exhaust Manifold - Front

Walker EPA Manifold Converter 16403

Walker EPA 16403 is a direct-fit catalytic converter with integrated exhaust manifold for select Nissan front applications. It is built with a stainless steel body and a ceramic substrate to support EPA emissions compliance on OBDII vehicles while maintaining OE-style fitment.

Key Features

• Direct-fit catalytic converter with integrated exhaust manifold
• Stainless steel converter body for corrosion resistance
• Ceramic substrate material
• 5-bolt welded flange inlet and 2-bolt welded flange outlet
• Oval inlet port and round outlet port
• Front-position application
• Includes front gasket; mounting hardware is included
• EPA-compliant design for federal emissions applications

Product Details

The Walker EPA product line is built for import and domestic OBDII vehicles that need an emissions-focused replacement with direct-fit installation. Part number 16403 is engineered as a manifold converter assembly, combining the exhaust manifold and catalytic converter into one unit for the front exhaust location. This configuration is used on 2004-2006 Nissan Altima and 2006 Nissan Sentra front applications, including federal and California emission models where permitted by law. This part cross-references Dorman - OE Solutions 674-659 for the same application.

Walker 16403 uses a stainless steel housing, a ceramic substrate, and welded flange connections to match the original exhaust layout. The overall length is 19 inches, with a 4-inch converter body length and a regular-grade construction.

What It Helps Address

• Check engine light related to catalyst efficiency faults
• Exhaust leaks at the manifold-to-pipe connection
• Failed or restricted catalytic converter performance
• Emissions test failures on EPA federal emission vehicles
• Noisy or damaged front exhaust manifold assembly

Installation Notes

Fits 2004-2006 Nissan Altima, front. Fits 2006 Nissan Sentra, front. Exhaust gasket is recommended, and the front gasket is included. Verify emission certification requirements before installation; this part is not legal for sale or use in California and other CARB-compliant states. It is legal in New York and Maine on EPA federal emission equipped vehicles only.

Quality Assurance

Walker Ultra EPA-Compliant Manifold Converters are designed to meet EPA emissions requirements for approved federal applications. Part number 16403 is built for direct-fit replacement use and follows the product line’s emissions-focused construction standards.