The Borla ProXS muffler is a universal, reversible oval muffler for custom and performance exhaust builds. It features an internal X-pipe that balances the dual flow paths for stronger flow and a refined exhaust note, with dual inlets and dual outlets for a true dual layout. Construction is 100 percent welded T-304 austenitic stainless steel with high-temperature continuous-filament fiber (CFF) acoustic packing for sound control, finished in a natural mill finish that can be brushed or polished before installation. The notched necks are designed for clamp-on installation using 1 inch wide band clamps (clamps sold separately; an un-notched weld-in version is offered as 400286). Borla exhaust is handmade in the USA and backed by the Borla Million-Mile Warranty.
Specifications:
- System type: universal oval muffler, reversible design
- Configuration: dual inlet / dual outlet with internal X-pipe
- Inlet diameter: 2.5 inch dual
- Outlet diameter: 2.5 inch dual
- Body: 4 inch x 9.5 inch oval
- Body length: 19 inch
- Overall length: 24 inch
- Neck style: notched for 1 inch wide band clamps
- Material: T-304 austenitic stainless steel
- Construction: 100 percent welded
- Made in the USA
- Part number: 400493
FAQ
What vehicles does the Borla 400493 ProXS muffler fit?
It is a universal muffler rather than a vehicle-specific part. It suits any custom or performance exhaust system that uses 2.5 inch dual inlet and outlet connections and has clearance for a 4 inch by 9.5 inch oval body, 19 inches long and 24 inches overall. Confirm pipe sizing and clearance for your application.
What does the internal X-pipe do?
The internal X-pipe crosses the two flow paths inside the muffler to balance exhaust pulses, which can improve flow and smooth the exhaust tone compared with a straight dual-chamber muffler.
How does it install?
The necks are notched for clamp-on installation with 1 inch wide band style clamps (not included), and the reversible design lets it mount in either orientation. An un-notched version for weld-in use is offered under part number 400286.
Is this a 50-state emissions legal or street legal part?
This is a universal weld-in exhaust component, not a complete vehicle-specific system. Emissions compliance and street legality depend on the complete exhaust system and the specific vehicle it is installed on, so a universal part sold on its own carries no standalone emissions certification. Confirm the requirements for your state and application before installing.
Where is it made and is it warrantied?
It is built in the USA from T-304 austenitic stainless steel and is backed by the Borla Million-Mile Warranty.
