Getting the most out of your Mustang GT or Dark Horse takes more than just a tune, it takes the right hardware to deliver it. This package pairs Steeda's custom tune with the Steeda RTD4 tuning device and the 4 HP Tuners credits your S650 needs, giving you everything required to unlock your ECU and load your calibration in one convenient bundle.
Everything you need, nothing left to track down. The 2024+ Mustang GT and Dark Horse require HP Tuners credits before a custom tune can be loaded to the ECU for the first time, and tracking down the right number of credits on your own can be confusing. This package includes the 4 credits required for your S650, along with the RTD4 device itself, so there's no guesswork and no separate purchase needed. Just unbox it, connect it, and you're ready to tune.
Wireless tuning made simple. The RTD4 connects to your Mustang through the OBDII port and pairs with the HP Tuners TDN app over Wi-Fi and Bluetooth, so there's no laptop, no USB cables, and no pulling the ECU. From your phone you can flash your custom calibration, read stock files, log data, and clear diagnostic trouble codes, all through a clean and simple interface built for real world use in the garage or driveway.
Tailored to your exact setup. Unlike the built-in, one size fits all maps you get from traditional handheld tuners, this is a custom tune written around your specific combination of modifications. Steeda's tuning team accounts for the parts you've installed, whether that's an intake, exhaust, or supporting mod, and makes the appropriate adjustments to air/fuel ratio, ignition timing, and fuel delivery so the calibration matches your Coyote. On a stock GT rated at 415 horsepower, this tune adds a peak gain of 21 horsepower and 12 lb-ft of torque. On the Dark Horse, rated at 419 horsepower from the factory, expect a peak gain of 14 horsepower and 1 lb-ft, with a broader curve gain of up to 20 lb-ft of torque through the mid-range where you feel it most on the street and at the track.
Revisions for 90-Days. This calibration is designed to work with popular bolt-on upgrades including cat-back exhaust systems, cold air intakes, mid-pipes, and similar supporting modifications. Rather than a generic base map, Steeda tunes the calibration around how these parts actually change airflow and exhaust flow on your Coyote engine, so your Mustang runs cleaner, stronger, and more consistently instead of just louder.
93 octane base tune with E85 flexibility. The standard tune is calibrated for 93 octane pump gas, giving you a safe and repeatable power gain for daily driving and weekend track days alike. For Mustang owners who want to take things further, an optional E85 tune add-on is available, allowing you to take advantage of E85's cooler combustion temperatures and higher-octane rating for even more aggressive timing and additional power potential.
Delivered online, built around your build. This is an online-order custom tune, so it does not include the in-person dyno pulls or hands-on tuning support of a true dyno day session. What it does include is a calibration written specifically to account for your modifications, giving you a more accurate and complete tune than a canned, pre-loaded map, plus the RTD4 hardware to get it onto your car, all in a single package that's fast, affordable, and easy to receive from anywhere.
Product Benefits
- RTD4 tuning device included
- 4 HP Tuners credits included
- No separate credit purchase needed
- Wireless tuning via Wi-Fi and Bluetooth
- Simple OBDII plug-and-play setup
- No laptop or USB cables required
- Custom tune, not a canned map
- Fits 2024+ Mustang GT and Dark Horse
- GT gains up to 21 HP and 12 lb-ft
- Dark Horse gains up to 14 HP, 20 lb-ft curve gain
- 93 octane base tune
- Optional E85 tune add-on available
- Compatible with cat-back exhaust, intakes, mid-pipes
- Revisions included for 90 days
- Convenient online delivery
About Steeda: For over 35 years, Steeda has been a trusted name in Ford performance, with a history rooted in racing and a reputation built on real world results. Steeda's tuning team develops every calibration with an enthusiast driven approach, ensuring each tune delivers safe, reliable, and repeatable power. From daily driven Mustangs to dedicated track builds, Steeda's team lives and breathes Ford performance.
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Product Specifications & Vehicle Fitment
Review the product details and confirm compatibility with your vehicle before ordering.
| Specification | Details |
|---|---|
| Vehicle Fitment | 2024, 2025 |
| Vehicle Trim | GT, Dark Horse |
