The quest for more horsepower is a never-ending journey for car enthusiasts. The aftermarket is flooded with products promising performance gains, but separating fact from fiction can be tough. To cut through the noise, we decided to put a popular modification to the test: the cold air intake. For our experiment, we needed a clean slate – a modern, low-mileage, and completely stock vehicle. Enter the perfect candidate: my father’s pristine 2021 Mustang Gt. And with Christmas around the corner, the timing couldn’t have been better for a horsepower-boosting gift.
Following my tradition of Mustang-themed holiday gifts for my dad, this year’s present was performance-oriented. He gets upgrades for his beloved Mustang, and I get to enjoy driving it afterward. Of course, the labor and the task of documenting the results fall on me. But seeing the horsepower gains on his S550 is far more rewarding than another generic gift.
Alt text: 2021 Mustang GT undergoing dyno testing to measure cold air intake performance gains.
To ensure accurate and consistent results, we opted for a Dynocom hub dyno at Aikman Performance. This type of dyno minimizes frictional loss, offering a more precise measure of power at the wheels. Our goal wasn’t just to tidy up the engine bay aesthetics, but to rigorously test the real-world impact of a well-designed cold air intake when paired with a performance tune. For this, we chose the Steeda Mustang GT ProFlow Open Cold Air Intake, which necessitates a tune, and the SCT Livewire TS+ Performance Programmer, utilizing a Steeda tune. Our testing would follow a structured approach: first, establishing a baseline horsepower figure in stock configuration, then assessing the gains from a tune-only setup, and finally, evaluating the combined effect of the Steeda cold air intake and its specific tune.
Before diving into modifications, I wanted to familiarize myself with the SCT Livewire TS+. Compared to my older SCT X4, the Livewire TS+ is a significant upgrade. Its vibrant 4-inch color touchscreen provides a user-friendly interface for monitoring gauges, navigating menus, data logging, and even timing performance metrics. Features like reverse camera integration further enhance its appeal. While both programmers offer similar storage and tuning capabilities, the Livewire TS+ offers a much more modern and intuitive user experience.
Alt text: SCT Livewire TS+ tuner showcasing its color touchscreen interface inside the cabin of a 2021 Ford Mustang GT.
Christmas arrived early at Aikman Performance in Cedar Park, Texas. While the shop was filled with high-horsepower race cars, our focus was on extracting more from the stock 2021 Mustang GT. Jerry Aikman, the owner and tuning expert, quickly loaded the Steeda tunes onto the SCT Livewire TS+.
After warming up the Mustang’s engine to optimal oil temperature, we were ready for our baseline dyno runs. The Coyote V8 roared to life, and even in its factory form, the sound was impressive. The initial dyno pull revealed a solid 410.8 horsepower at the wheels. A second run confirmed this figure, establishing our starting point.
Next, we explored the potential of a tune-only upgrade. We uploaded the Steeda tune designed for a stock Coyote engine. This tune alone added a noticeable 15 horsepower, bringing the Mustang GT to 425 horsepower on the dyno. This demonstrated the inherent restrictions within the factory engine mapping and the immediate benefits of a performance tune.
Excited by the tune-only gains, we moved on to the main event: installing the Steeda ProFlow Open Cold Air Intake. Aikman Performance was equally eager to see the combined results. The factory intake system was straightforward to remove with basic tools, creating ample space for the new Steeda intake.
Alt text: Components of the Steeda ProFlow Open Cold Air Intake kit ready for installation on a Ford Mustang GT.
With the Steeda intake installed and the corresponding CAI tune loaded, we ran two more dyno pulls. The results appeared on the screen – an additional 10 horsepower. The Steeda cold air intake and its conservative tune pushed the final dyno figure to 434.9 horsepower at the wheels. This represents a significant gain from just a tune and intake, validating these as effective initial modifications.
Alt text: Dyno graph illustrating the horsepower and torque increase achieved with a cold air intake and tune on a Mustang GT.
In total, we achieved a gain of 24.1 horsepower and 21.8 lb-ft of torque through the cold air intake and tune. While dyno numbers are valuable, the real-world driving experience is equally important. Out on the Texas Hill Country roads, the Mustang GT felt noticeably more responsive, especially in the mid-range and upper RPMs. The engine note was enhanced, and acceleration felt more immediate. This cold air intake and tune combination provides a tangible improvement in both performance and driving enjoyment for the 2021 Mustang GT, making it a worthwhile upgrade for any enthusiast looking to unlock more from their ride.
