This Mazda Miata Makes Well Over 400 Horsepower, Thanks to a Ford Mustang EcoBoost Engine Swap

The Story

And if you like the sound of that, you should be able to have your own ND-gen MX-5 outfitted with the tuned turbo four by the end of the year.

GeauxMotoThe ND-generation Mazda Miata is already a beloved performance car without any external help, but . What if you swapped its naturally-aspirated engine for a forced-induction mill to more than double the power?. It may sound a little mad, but tuning shop GeauxMoto has done exactly that, dropping the 2.3-liter turbocharged four-cylinder EcoBoost engine from Ford’s Mustang into the Japanese roadster. And the results are fierce.

GeauxMoto, based in Hammond, Louisiana, is a one-stop shop that’s focused on track-car builds and capable of everything from frame repairs and full paint jobs to engine assembly and dyno tuning, and Mazda Miatas are unsurprisingly frequent visitors. So, the company decided to see if a tuned EcoBoost engine swap in the ND-generation MX-5 would prove more reliable than previous turbo kits. The resulting, highly successful testbed vehicle was dubbed the EcoYata, and its 450 horsepower and 400 lb-ft of torque speak for themselves.

“We started out racing a boosted NC Miata that blew up countless times. This encouraged us to switch to an OEM boosted motor to get rid of a lot of the hassle from fitting an aftermarket turbo manifold and figuring out how to plumb water lines that actually flow properly,” Dayton de la Houssaye of GeauxMoto said to Road & Track. “The EcoBoost ticked all the boxes, and makes great OEM power numbers at 315 horsepower and 350 ft-lb [of torque], while being one of the biggest-displacement turbo four-cylinder options with really tight exhaust packaging. Another upside with these engines is you can still buy them brand new at Ford dealerships with a warranty.”.

Fitting the larger displacement engine into the Miata wasn’t particularly challenging, according to the shop. Even paired with Ford’s MT-82 six-speed manual transmission, de la Houssaye said the EcoBoost motor fits into the Miata’s engine bay without modification to the subframe. GeauxMoto scanned the entire powertrain and chassis to confirm it would work; it’s extremely tight in a few spots, with shaving a few tabs on the exterior of the transmission and some trimming of the windshield cowling required, de la Houssaye explained, but the fitment is otherwise factory-spec.

Once the team at GeauxMoto confirmed the new engine and transmission could slide inside the ND, they went to work tuning the motor for a reliable power increase. With a ported head, an upgraded Garrett turbocharger, and a new intake and exhaust system, the EcoBoost-swapped Miata put down 460 horsepower and 400 lb-ft of torque on an E85-specific dyno tune provided by Engineered Motorsport Solutions, and 397 horsepower and 341 lb-ft of torque when tuned conservatively for California-grade 91-octane gasoline. Those power figures both include a version of the EcoBoost engine with fortified Mountune internals, which GeauxMoto recommends for engine longevity. A 315-hp version of the swap kit is also available without the forged engine internals; GeauxMoto has reliably run this non-forged internal version of the kit up to 440 horsepower. Either way, that’s a lot of power in a car that weighs under 2400 pounds.

“It’s a Miata on steroids, for sure. Basically, imagine a normal ND but with a near-immediate torque hit that’s twice as hard as your stock motor at peak power,” de la Houssaye said. “On top of the wonderful power and fun torque curve, you get lots of turbo noise. With the OEM baby turbo, these engines hit peak torque around 3000 rpm, which we limit to 300 ft-lb for longevity.”.

The best part of this swap is, the Miata retains all its factory functions. GeauxMoto wanted to make the engine swap as OEM-like as possible, so they connected a Ford Performance ECU to Mazda’s powertrain control module, allowing the stop/start button, electronic power steering, ABS, air conditioning, window switches, and mirrors to function as normal. Even the gauge cluster will appear like it usually does, despite the addition of a foreign engine. Mazda’s factory differential, front and rear subframes, interior pieces, electronic power steering rack, and exhaust all bolt to the Ford powertrain without much modification, too.

The kit is not quite ready for purchase, but GeauxMoto expects to launch it before the end of the year. The total cost for the swap will be around $12,000, excluding the donor vehicle and the new engine and gearbox; buying a crate engine directly from Ford will cost around $7000, plus an additional $4000 for an MT-82 manual transmission. GeauxMoto says it estimates a complete swap would take around 48 hours, plus some additional time for dyno tuning. So if you’re looking for a reliable way to boost your Miata’s power output, you may need to make a call to Louisiana soon.

Why It Matters

Once the team at GeauxMoto confirmed the new engine and transmission could slide inside the ND, they went to work tuning the motor for a reliable power increase.

CarMotion Daily’s Take

The total cost for the swap will be around $12,000, excluding the donor vehicle and the new engine and gearbox; buying a crate engine directly from Ford will cost around $7000, plus an additional $4000 for an MT-82 manual transmission. Watch this space over the coming weeks. Markets rarely reward single announcements — execution over the next two to four quarters is what closes the gap between press release and customer. How this lands depends less on the announcement itself and more on the rollout, dealer support, and after-sales story behind it. Specifics on pricing, availability, and regional rollout will tell us whether this moves from headline to delivery. Independent verification and follow-up coverage from rival outlets tend to firm up the picture within days.