Roush421994 Phase2 Supercharger Upgrade Kit 727HP for 15-17 Ford Mustang

Vehicle Fitment

• 2015-2017 Ford Mustang (EcoBoost, GT, GT Premium, GT 50 Years LE, Shelby GT350, Shelby GT350R, V6)

Features

• Phase 2 supercharger upgrade kit builds on ROUSH Phase 1 system for higher output
• Delivers approximately 727 hp and 610 lb-ft of torque with upgraded calibration
• Includes preset plug-and-play digital fuel pump controller for safe fuel delivery
• Smaller diameter 80 mm supercharger pulley increases boost level
• Colder heat-range spark plugs included for efficient combustion under boost
• ROUSH Diagnostic Tool (RDT) reflash voucher provided for calibration download
• Designed to retain broad drivability and engine reliability under daily use
• Engineered for consistent performance across varying conditions

Specifications

• Part Number: 421994 / RSH421994
• Application: 2015-2017 Ford Mustang
• Compatible Engines/Trims: EcoBoost, GT, GT Premium, GT 50 Years LE, Shelby GT350, Shelby GT350R, V6
• Rated Output: ~727 horsepower @ ~6,850 rpm, ~610 lb-ft torque
• Supercharger Upgrade Type: Phase 1-to-Phase 2 conversion
• Includes digital fuel pump controller and high-boost pulley
• Installation: Moderate; requires access to supercharger and PCM reflash via RDT
• Warranty: Extended ROUSH supplied parts warranty included

Included Components

• 1x 80 mm supercharger pulley
• 1x Preset plug-and-play digital fuel pump controller
• 8x Cooler heat-range spark plugs
• 1x ROUSH Diagnostic Tool (RDT) reflash voucher

Product Description

The Roush 421994 Phase 2 Supercharger Upgrade Kit is a high-performance forced induction upgrade designed for 2015 to 2017 Ford Mustang models. Building on ROUSH's Phase 1 supercharger offerings, this conversion kit increases boost and airflow through a smaller 80 mm pulley and enhanced fuel delivery, resulting in approximately 727 horsepower and 610 lb-ft of torque - a significant gain over the stock and Phase 1 systems. The package includes a preset digital fuel pump controller and colder heat-range spark plugs to support the higher boost levels with reliable combustion.

Installation typically requires mechanical experience and access to the ROUSH Diagnostic Tool to flash the updated Phase 2 calibration to your Mustang's PCM. The kit is engineered to blend increased performance with everyday usability, maintaining drivability and heat management while delivering elevated power. This upgrade is ideal for Mustang enthusiasts seeking a substantial horsepower boost without building a full custom forced induction setup.