2015-2017 Ford Mustang GT Roush Phase 1 to Phase 2 Supercharger Upgrade Kit | 421994

Mustang GT Roush Phase 1 to Phase 2 Supercharger Upgrade Kit Features:

• Boosts output to 727 horsepower
• Delivers 610 lb-ft of torque
• Plug-and-play digital fuel pump controller
• Colder heat range Ford spark plugs
• 80mm pulley increases boost levels
• Installs without replacing supercharger belt
• Includes Roush Diagnostic Tool calibration
• 3-year/36,000-mile parts-only warranty
• 50-state emissions legal for 2015-2016
• CARB approved for 2017 California models

Turn Your Phase 1 into a True Powerhouse

If you’ve already experienced the thrill of the Roush Phase 1 supercharger on your 2015-2017 Mustang GT, the Phase 2 upgrade is your next step toward even more heart-pounding performance. This kit is designed to take your Coyote-powered Mustang from an already impressive 670 horsepower to a jaw-dropping 727 horsepower, along with 610 lb-ft of torque. The best part is that it builds on the components you already have, adding carefully engineered upgrades that maximize boost, fuel delivery, and calibration. Whether you’re looking for more straight-line speed, faster lap times, or just the satisfaction of knowing your Mustang has the muscle to back up its looks, the Phase 2 kit delivers the goods without sacrificing drivability.

Engineered Upgrades with Real-World Benefits

Every part of the Phase 2 kit is designed to work seamlessly with your existing setup, making installation straightforward and avoiding unnecessary downtime. The smaller 80mm supercharger pulley increases boost pressure and installs in minutes without requiring a new belt. A plug-and-play digital fuel pump controller boosts fuel delivery safely and reliably, while colder heat range Ford spark plugs keep combustion temperatures in check for consistent power under heavy load. Once the hardware is in place, the included Roush Diagnostic Tool makes loading the Phase 2 calibration quick and painless, ensuring your Mustang runs smoothly with the new upgrades. Backed by a 3-year/36,000-mile parts-only warranty and 50-state emissions compliance for 2015-2016 models (with California approval for 2017), this kit offers both performance and peace of mind. It’s the perfect way to unlock your Mustang’s full potential while keeping that factory-like refinement you love.

Vehicle Fitment: 2015, 2016, 2017 Ford Mustang GT 5.0L V8

50-State Legal Note: This kit is compliant with 50-State emissions regulations for 2015-2016 Mustangs (CARB E.O. #D-418-29) and is approved for sale and installation on 2017 model year vehicles in the state of California (CARB E.O. #D-418-34).