A Behind-the-Scenes Look at How STILLEN Engineers and Manufactures the Nissan Z Cat-Back Exhaust System

Take a look at the precision and craftsmanship that goes into every Nissan Z Cat-Back Exhaust System built here at STILLEN. Every exhaust system we produce is designed and manufactured entirely in-house at our Costa Mesa, California facility, and the Nissan Z exhaust is no exception.

CNC Band Saw and Mandrel Tube Bending

The manufacturing process begins with 2.5-inch stainless steel tube, which is cut in bundles using STILLEN's hydraulic CNC-controlled band saw. From there, the cut tubes move to our CNC mandrel tube benders. Mandrel bending is critical for a high-performance exhaust because it preserves the interior diameter through every bend, ensuring unrestricted exhaust gas flow and maximum performance. Every tube coming off the bender is verified in our proprietary bend check fixtures to confirm it meets our exact specifications before moving to the next stage.

CNC Milling and X Pipe Fabrication

The STILLEN X pipe is engineered for optimum exhaust gas flow and performance. To achieve the precision needed, the X pipe tubes are loaded into our CNC milling machine and machined for a perfect, repeatable fit into the welding fixture.

Once machined, the tubes and weld fixture move to the production welding booths, where our skilled craftsmen TIG weld the tubes and braces together to form a single, high-flow X pipe.

Merging two 2.5-inch exhaust tubes into a single tube would typically require a tube diameter exceeding 4 inches -- far too large to route through the chassis cleanly. A true dual 2.5-inch exhaust also did not deliver the sound characteristics we were after for this platform. The X pipe design allows us to merge the two exhaust banks in a way that optimizes exhaust gas flow without creating restriction, while also delivering the aggressive sound signature the Z deserves.

STILLEN Muffler Assembly

Muffler assembly begins with our production team assembling the perforated tube inner core, then forming the end caps for the muffler body. The inner core and one end cap are tack welded together before the muffler moves to the assembly area for insertion of high-temperature ceramic wool.

Once the wool insert is in place, the mufflers return to welding, where the outer cap is tacked on. At this stage, the mufflers are sent to an outside vendor for polishing before returning to STILLEN for final welding. This is the only step in the entire exhaust manufacturing process that takes place outside our facility.

STILLEN Proprietary Rotational Welding Positioner

After the polished mufflers return from the outside vendor, they are mounted on our proprietary rotational welding positioner -- a piece of tooling designed and built by our own engineering team. This positioner allows our TIG welders to precisely control the rotation speed and orientation of the muffler during the final weld pass, resulting in a consistent, high-quality TIG welded finish. The mufflers are intentionally left with a natural burn finish to showcase the quality of the TIG craftsmanship.

Final Assembly and Weld Fixtures

Every Nissan Z exhaust system goes through our pre-assembled weld fixtures for final welding and assembly. These fixtures locate and align all key components to ensure perfect, repeatable fitment across every unit produced.