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Roush Phase 1 to Phase 2 Supercharger Upgrade Kit - 727 HP (15-17 GT)

Item 390770
Market Price $1,130.99 You Save 5% ($55.00)
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      Review & Installation Video

      Product Information

      Features, Description, Reviews, Q&A, Specs & Installation


      • Roush Phase 1 to Phase 2 Supercharger Upgrade Kit
      • Upgrade to 727 Horsepower and 610 lb-ft of Torque
      • Includes 80mm Pulley, NGK Spark Plugs and Plug & Play Digital Fuel Pump Controller
      • Roush PCM Flash Voucher Card Included
      • 3 Year / 36,000 Mile Limited Warranty on Roush Parts Only
      • Fits 2015-2017 GT Mustangs with a 670HP Roush Phase 1 TVS Supercharger Kit


      More Horsepower and Torque! Increase the power and performance of your current 670 HP Roush R2300 Phase 1 Supercharger to an impressive 727 horsepower and 610 lb-ft of torque with a Phase 2 Supercharger Upgrade Kit.

      Kit Includes. The Roush Phase 1 to Phase 2 Supercharger Upgrade Kit includes a new 80mm S/C Pulley, a preset plug and play digital fuel pump controller, cooler range NGK spark plugs, ROUSH PCM Flash Voucher Card and installation instructions.

      Roush Performance Quality - Guaranteed. Roush is known for a rich tradition of excellent racing performance engineering at the highest level of OEM quality and design. This Supercharger upgrade kit features a 3 Year/36,000 Mile Parts limited warranty (ROUSH Supplied Parts Only).

      Upgraded ROUSH PCM Calibration. ROUSH® PCM calibration is a success of engineering that maximizes the power of the system. ROUSHcharger owners will receive a ROUSH® PCM Flash Voucher Card, which is used to obtain the specific calibration needed for your Mustang and requires ROUSH Diagnostic Tool (RDT) software and a J2534 Pass-Through device to upgrade your PCM (software and pass-through device not included). If you don't have access to a pass-through device, you have the option of sending your PCM back to Roush, where they will flash your PCM for an additional $100 fee.

      Application. This ROUSH Phase 2 Supercharger Upgrade Kit works with both manual and automatic 2015-2017 GT Mustangs equipped with the Coyote 5.0L DOHC 4 valve V8 engine and a ROUSH R2300 Phase 1 TVS Supercharger that produces 670 horsepower. This voids optional Roush limited powertrain/drivetrain warranties.

      Fitment: 2015 2016 2017 Details

      MPN# 421994

      CA Residents: WARNING: Cancer and Reproductive Harm -


      Customer Reviews (11)

      Write a Review

      Ratings Summary

      4.8 out of 5 overall rating from 11 customers

      Installation Time: Full Day

      Installation Cost: $100-$250

      • November 10, 2019

        5 2017 GT - Tooner Installation Time: Shop Install Installation Cost: $250-$500

        Roush phase 2 upgrade kit

        very pleased with the power gains with the phase 2 kit. It took the Roush dealership around 4 hours for total install and tune. it is def a worth while upgrade! If you didn't need tires before you will most def will after.

        Helpful (0)
      • August 26, 2019

        5 2017 GT - BigMike Installation Time: Afternoon

        Stage 2 upgrade

        It has awoken my pony before stage 2 I’m running 11.9’s in 100degree weather now I should be at least mid to low 12’s,better throttle response too

        Helpful (0)
      • July 23, 2019

        5 2019 GT - WlknTal Installation Time: Shop Install Installation Cost: $100-$250

        THE CYOT

        Calculating the 13.75 loss going through the 6R80 trans with the Roush phase 1 kit I figure the phase 2 should get me around 625RWHP mark. So for the price of this unit plus install cost it fairly cheap horsepower, not to mention if I choose get a custom tune I could get close to 660 RWHP out of it.

        Helpful (0)
      • July 17, 2019

        5 2015 GT - RobertJ Installation Time: Afternoon

        Roush Phase 1 to Phase 2

        Install was easy and I would give it 1 out of 3 wrenches! I can feel the difference in power from the Phase 1 kit. This Phase 2 kit is incredible!

        Helpful (1)
      • May 11, 2018

        5 2015 GT - CecilP Installation Time: Shop Install

        Roush phase 2 kit

        Good product, no problems. Had to drive it home in the rain (first time). Drivability great, you can feel more power.

        Helpful (5)
      • December 20, 2017

        4 2016 GT - MikeJ Installation Time: Afternoon

        Good product with one problem

        This is a nice kit for a fair price to push it over 700hp. Drivability is still very good and the power increase can be felt immediately. Install is very simple, HOWEVER, I did have an issue with the PCM flash. When using the Roush software, you are prompted to put in the PCM tear tag number. Well, 2016 and up Mustangs don't have the tear tag info physically on the PCM like 2015 and prior, and getting the info can be a huge PITA if you don't have FMC dealer access. This isn't a big deal, but something customers need to be aware of if doing the install themselves so they don't brick their cars until they can get ahold of Roush.

        Helpful (8)
      • December 15, 2017

        5 2015 GT - Hellfighter60 Installation Time: Shop Install Installation Cost: $250-$500

        Roush Phase 2 Supercharger Upgrade Kit

        This kit definitely improved the horsepower on my Roush!. Gof it at a great price during Black Friday.

        Helpful (7)
      • June 09, 2017

        5 2015 GT - LarryS Installation Time: Shop Install Installation Cost: $100-$250

        Roush Phase 1 to Phase 2 2015 Mustang GT

        Nice increase in power, runs great. Highly recommend a stronger clutch to take advantage of the horse power increase. I had a Mcleod RXT 1000 HP installed, great for street driving plus great performance. That Mustang is great, lots of fun.

        Helpful (8)
      • February 03, 2017

        4 2015 GT - Michael Installation Time: Afternoon

        Phase 2

        20 Rear wheel horsepower gain....... Was hoping for a little more, but not bad!

        Helpful (10)
      • June 23, 2016

        5 2015 GT - captmike Installation Time: Afternoon

        And the winner is?

        Nice upgrade, turned that GT into an animal, now suspension to keep the animal under control !!! Thank you American Muscle for such quick delivery, worth the wait!!!!' Capt. Mike

        Helpful (8)

      Questions & Answers (14 answers)

      5 Top Rated Questions

      do i need to get my pcm reflashed if i already have the 670 hp tune with this upgrade?

      • You will need to reflash your PCM as the calibration voucher for the upgrade will be included.

      Helpful (1)

      Will this fuel pump booster handle more power with new injectors and a smaller pulley than the 80mm it comes with?

      • This kit is designed to upgrade the Phase 1 kit to the Phase 2 kit for more performance.

      Helpful (0)

      Do you think this will fit the 2018GT or are they different in the engine bay?

      Do u need anything else for this or u can just buy this and it will increase your horsepower

      • All parts to complete installation will be included. Please note that a Roush R2300 Phase 1 TVS Supercharger is required.

      Helpful (0)

      I have a 2015 mustang GT, I'm not a car guy and I want to know exactly what is this roush phase one to two is and how does it work? Thanks

      • This kit will allow you to upgrade the Roush Phase 1 supercharger to a Phase 2 which will provide better performance.

      Helpful (0)
      Post Your Question
      9 More Questions
      Will it pass CA smog? 1 answer
      Can any Ford dealer flash this or does it have to be a Roush certified dealer? 1 answer
      Does the upgrade decrease miles per gallon? 1 answer
      What’s the part number on the spark plugs? 1 answer
      Will my warranty be voided with the phase 2 upgrade kit? 1 answer
      Whats typical install time for a shop to install? 1 answer
      Will I be able to hear my blower after installing the phase 2 kit on my roush? I really miss the blower whine! 1 answer
      would i have to upgrade fuel injectors on my 2015 GT? 1 answer
      I have the 2015 Mustang gt with the ford racing supercharger installed on my car. I was wondering If the roush phase 2 supercharger upgrade kit will work with the ford racing supercharger. I know the supercharger was developed with Ford and Roush, however I have not seen any advertisement for the ford racing phase 2 upgrade. 1 answer

      Installation & What's in the Box

      Installation Info

      What's in the Box

      • (1) Preset Plug and Play Digital Fuel Pump Controller
      • (8) NGK Spark Plugs
      • (1) 80mm Supercharger Pulley
      • (1) ROUSH PCM Flash Voucher Card
      • Installation Instructions

      Tech Specs

      Will It Fit My Mustang

      • GT - 15, 16, 17

      This Roush Phase 1 to Phase 2 Supercharger Upgrade Kit is specifically designed for 2015-2017 GT Mustangs with 670hp Roush TVS Supercharger Kit installed.

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