Roush 421837-BLK Mustang V6 EcoBoost Axle-Back Exhaust Black Tips 2015-2026

Vehicle Fitment

• 2015-2017 Ford Mustang V6 (3.7L V6, Coupe and Convertible)
• 2015-2026 Ford Mustang EcoBoost (2.3L I4, Coupe and Convertible, without Active Valve Exhaust)

Fitment Notes

• Does not fit 2019+ Mustang EcoBoost models equipped with the factory Active Valve Exhaust option.
• Installation requires cutting of the factory exhaust piping - a reciprocating saw is recommended. No welding is required.
• Compatible with the factory rear exhaust valance for a clean, OEM appearance.
• Uses OEM hanger locations and mounting points - no drilling or modifications to the body required.
• Does not fit Mustang GT (5.0L V8) - see Roush 421834-BLK for GT applications.

Features

• T-304 stainless steel construction throughout for corrosion and stain resistance
• Full mandrel-bent tubing maintains a constant inner diameter for maximum flow and reduced backpressure
• Single-tip high-flow mufflers deliver an aggressive, throaty tone at idle and acceleration without interior drone
• Dual-wall 4 in. black powder-coated exhaust tips for a bold, stealthy appearance
• Zero impact on emissions devices - emissions-compliant design
• Uses OEM hanger locations - no welding, drilling, or body modifications required
• Roush Limited Lifetime Warranty

Specifications

• Part Number: 421837-BLK
• Exhaust Type: Axle-Back, Split Rear Exit
• Material: T-304 Stainless Steel
• Tip Style: Dual-Wall, Round, Black Powder-Coated
• Tip Diameter: 4 in.
• Inlet Pipe Diameter: 2.5 in.
• Muffler Style: Single-Tip High-Flow Open-Chamber
• Finish: Black Powder-Coated Tips / Natural Stainless Body
• Welding Required: No
• Cutting Required: Yes - Factory Exhaust Pipe Cut Required
• Emissions Compliance: Yes - Zero Impact on Emissions Devices
• Warranty: Roush Limited Lifetime Warranty
• Quantity: Sold as a Complete Kit (Driver and Passenger Side)

Included Components

• 1x Driver Side Muffler Assembly
• 1x Passenger Side Muffler Assembly
• 2x 4 in. Black Dual-Wall Exhaust Tips
• 4x Clamps
• 1x Installation Instructions

Product Description

The Roush 421837-BLK is a T-304 stainless steel axle-back exhaust system designed for the 2015-2017 Ford Mustang V6 and 2015-2026 Mustang EcoBoost without factory Active Valve Exhaust. The system replaces the factory mufflers with Roush's single-tip high-flow open-chamber mufflers, delivering a deeper, more aggressive idle and a throaty, raspy acceleration tone without unwanted interior drone. Full mandrel-bent tubing maintains a constant inner diameter throughout for maximum exhaust flow and reduced backpressure compared to the factory system.

The dual-wall 4 in. black powder-coated exhaust tips provide a bold, stealthy rear-end appearance that fills the factory valance opening cleanly. Installation uses OEM hanger locations and mounting points with no welding or drilling required - the only modification needed is cutting the factory exhaust pipe before sliding the Roush muffler assemblies into place and securing with the included clamps. The system is emissions-compliant with zero impact on emissions devices. Backed by the Roush Limited Lifetime Warranty against defects in materials and workmanship.