Roush Supercharger Upgrade Kit Phase 1 To Phase 2 750HP GT 2018-2020



  • 50 HP/ 60 TQ Over Phase 1
  • Total Gains of 290 HP
  • 50 State Legal
  • USA Made
MSRP $624.00
You save $24.01

Roush 750HP Phase 1 To Phase 2 Supercharger Upgrade Kit for 2018, 2019 and 2020 GT Mustangs.

Roush did a great job with their new Phase 1 Supercharger kit for the 2018-2020 GT Mustang. If you’ve installed one in your S550, you’ve surely enjoyed the 240 horsepower increase compared to stock. Roush also did a great job with their Phase 2 kit, which offers an additional 50 horsepower and 60 torque over Phase 1. If you’re ready to take that next step, this Phase 1 to Phase 2 Kit (422185) gives you everything that sets the Phase 2 Kit apart – so you can achieve 750 horsepower and 670 torque while staying CARB legal in all 50 states.

Features and Benefits:
- 50-State Legal
- Power is Increased to 750 Horsepower and 670 lb-ft of Torque
- Additional 50 Horsepower and 60 lb-ft of Torque Over Phase 1
- Larger Full-Face Low Temperature Radiator Improves Cooling Capacity
- Phase 2 calibration Delivered Through Roush Diagnostic Tool (RDT)
- Includes 3-year/36,000-mile Limited Powertrain Warranty (when properly installed by a Ford dealer or an Automotive Service Excellence-certified technician)
- Made in the USA

The upgrade kit includes a high-capacity low temperature radiator and upgraded ROUSH calibration, which provide increased cooling capability and work with Eaton’s TVS R2650 technology for greater power output. The larger LTR and optimized calibration work in harmony to improve cooling and optimize performance, giving drivers extra laps at the track all while carrying a CARB approval number (E.O. #D-418-33) and being legal in all 50 States!

Additional Notes:
- This kit is NOT compatible with the BULLITT edition Mustangs.
- This Kit and the included Roush Calibration are NOT compatible with any 2018-2020 5.0L Mustang meant for distribution outside of North America that are designed to meet Euro 6.2 emission standards.

- Low Temperature Radiator Assembly
- LTR Assembly Lower Bracket
- LTR Assembly Foam Seal
- Roush Diagnostic Tool (RDT) Re-Flash Voucher Card

Vehicle Fitment:
- 2018-2020 5.0L Mustangs with Roush Supercharger System (P/N: 422090) - Manual or Automatic
- 2018-2020 Roush RS3 Phase 1 Supercharged Mustangs

Tech Tips:
- The use of fuel additives (i.e. octane boosters) is NOT recommended.
- Calibration is optimized for 93 Octane Fuel but it is also compatible with Premium fuel (91 octane or higher). Premium and/or 93 Octane Fuel is required to prevent “spark-knock” or detonation under certain operating conditions.
- Operating your engine without the Roush PCM recalibration will result in engine damage or failure and will void your warranty.

California Residents: Proposition 65 Warning

This item is 50-state legal (CARB E.O. Number D-418-34)

Installation Difficulty


Intermediate skill is required for this installation.

Vehicle Fitment

This product will fit the following Mustang years:

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