Geaux Moto’s Ford EcoBoost ND Miata Makes 450 HP
A Louisiana shop called Geaux Moto has done something that sounds like a fever dream at a car show: dropped a turbocharged Ford EcoBoost four-cylinder into an ND Miata and tuned it to 450 horsepower at the wheels. But this isn’t a shock-value build. It’s one of the most comprehensively engineered cross-brand swaps in recent memory, and the technical decisions behind it are what make it worth paying attention to.
Geaux Moto, based in Hammond, Louisiana, sells a complete 2.3-liter EcoBoost swap kit for the ND chassis under the name “Ecoyata.” Their development car—the one that just surfaced with full technical breakdown and dyno footage—pairs that engine with a Mustang six-speed manual, a Varis-engineered aero package, and enough cooling infrastructure to keep everything honest on a track day. The result weighs 2,378 pounds and, on a street tune, makes 321 horsepower. Unleashed, it makes 450.
The Engine: A Focus RS Heart With A Bigger Turbo And Dual Wastegates
The 2.3-liter EcoBoost is the same turbocharged inline-four found in the Focus RS and the four-cylinder Mustang, and Geaux Moto doesn’t run it anywhere near stock. Their demo car uses a built Mountune bottom end, a larger twin-scroll Garrett turbo, and dual wastegates. On the dyno, a customer car hit 460 horsepower and 393 lb-ft of torque. The Geaux Moto development car itself is rated at 450 hp at the wheels—with ethanol in the tank.
For street use, the tune drops to 321 hp and 378 lb-ft, which keeps the car manageable without neutering it. The oiling setup uses a Focus RS oil pan with added baffling to handle the lateral loads an ND sees in cornering. Cooling is handled by a larger radiator and intercooler, plus supplementary radiators tucked into the factory foglight housings—a clean solution that keeps the nose looking stock while solving a real thermal problem.
The Transmission Swap Is The Hard Part
Fitting the engine is actually the simpler half of this build. The EcoBoost drops in with minor trimming around the cowl and some accessory repositioning. The transmission is where the engineering gets complicated.
Geaux Moto runs the Mustang’s MT-82 six-speed manual, which creates an immediate problem: the ND Miata uses a Power Plant Frame—a rigid ladder structure that connects the transmission directly to the rear differential, replacing a conventional transverse crossmember. Swap in a non-stock gearbox and that entire system needs a rethink. Geaux Moto engineered an alternative in-house, including CAD-designed motor mounts and transmission mount. Behind the MT-82 sits an OS Giken limited-slip differential installed in the stronger stock casing. The shop is also developing a tubular rear subframe to eventually accommodate a Ford 8.8 rear end, which would open the door to even more power without stressing the stock housing.
576 Pounds Of Downforce From A Varis Aero Kit
The aero package is what separates this Miata from other high-horsepower ND builds. Geaux Moto runs a Varis-engineered kit—the enormous rear wing is sourced from Varis, while the carbon-fiber front splitter is built in-house to a Varis design. Together, they generate 576 pounds of downforce at 100 mph. That figure matters when you’re putting down nearly twice the power of a stock ND through 285/30ZR17 tires front and rear.
The car also runs a dual-ECU electrical setup: a Ford Performance ECU handles the EcoBoost engine, while the stock Mazda PCM remains in place to retain factory functions including ABS and electric power steering. Geaux Moto developed a proprietary “black box” to get the two modules talking to each other—which means the factory throttle pedal, start/stop button, and instrument cluster all work as intended.
Street-Capable Despite The Numbers
For all its track-day hardware, this Miata hasn’t been stripped out. Air conditioning is retained. The interior keeps most of its stock trim, with Sparco seats and a custom roll bar engineered to fit under the DG hardtop without requiring a full cage. It’s a car you could drive to a track day, run hard, and drive home—which is exactly the point.
Geaux Moto is positioning the Ecoyata as a kit product, not just a one-off showpiece. Motor mounts, transmission mount, and roll bar are all slated to be offered as purchasable components, and the shop’s YouTube channel documents the engineering decisions in detail for anyone looking to understand what a properly executed swap actually involves. This is builder-porn with receipts.
The ND chassis has always had more potential than its 181-horsepower factory output suggests. Geaux Moto’s Ecoyata build makes the case that with enough engineering discipline—not just a big turbo and a prayer—a cross-brand swap can produce something that rivals purpose-built performance cars. Gearheads hoping to see this kit reach wider availability should keep an eye on the Hammond shop.
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