The Ecotec Miata Swap is the Bargain of the Century

Full Disclosure: MT Motorsports let me drive their car: that’s it, this isn’t an advertisement.

MT Motorsports is a Richmond Hill performance shop that’s obsessed with building fast Mazda Miatas. They do everything from turbocharging stock cars to monstrous LS swaps. More recently, they’ve become known for producing one of the strangest and most affordable Miata engine swap kits on the planet: GM’s 2.4l Ecotec swap.

At stock power levels, the Miata is plenty of fun. But, when put next to nearly anything modern, it becomes apparent how painfully slow these cars are from the factory. A 2016 Honda Civic would walk away from my NB Miata with ease in a drag race. If you take your Miata racing, (it’s one of the most raced cars on the planet) straights become your worse enemy as muscle cars come tearing up your rear.  The obvious solution for a moderate power increase is forced induction, and there are numerous turbo and supercharger kits on the market that promise between 200 whp – 250 whp reliably. Unfortunately, boosted Miatas almost always run hot on the track. As my friend Rajan (owner of a turbocharged 1.8L Miata) put it "it would be a dream-come-true if I could do five laps without needing to cool down."

Matt from MT Motorsports is involved in every aspect of the Ecotec swap program, and the more he talked, the more wide-eyed I became. The swap kit retails for $1899, and that will get you everything except for a header and an intake manifold — those can be pulled off of any Ecotec powered car and repurposed. For the motor itself, because GM stuck these things in everything (Colbalts, Malibus, Equinoxs, Solstices, you name it), low mileage examples can be sourced for around $500. Aside from that, the two wiring harnesses need to be spliced together, you’ll need to source a throttle pedal from a Cadillac CTS to account for the Ecotec’s throttle by wire, and that’s it. No chassis changes, no steering rack modifications, nothing. How difficult is it? According to Matt, “it's no more difficult than swapping out a Miata motor for a Miata motor." In their Ecotec swapped NB, they did the whole thing over two days. Come the third day, they drove the car to the Tail of the Dragon and back. That same car went on to do 20,000 km of daily driving with nothing more than basic maintenance.

Fabricating a swap kit and making it work is one thing. These guys have been testing their Ecotec cars for years now by racing the shit out of them. Their Ecotec Chump-Car saw 70 hours of endurance racing, usually 8 hours at a time, without a single engine-related issue and a radiator of “unknown origin.” As for power, MT achieves 200 wtq and 200 whp thanks to a custom 91 octane tune, which is remarkable considering its original 169 hp – 175 hp factory rating. If you’re concerned about the heavy GM engine throwing off Mazda’s perfect weight distribution, don’t be – the Ecotec motor is within five pounds of the original motor.

Now, it was time for me to drive the Ecotec powered NB. The car in question was dyno’d at 210 whp with a stock Mazda exhaust. In short, it’s fast — think factory Mustang GT fast: MT claims it does a 13-second quarter mile. This isn’t the type of car that’s terrifying under acceleration. It feels like the right amount of power for a car of its weight and more than enough to keep me grinning. Anything less would feel a little slow and adding anything more is unnecessary. There’s torque everywhere. At 2000 rpm where the factory BP motor would feel gutless, the Ecotec pulls effortlessly. After driving an Ecotec Miata, my stock NB almost felt broken. I found myself short-shifting because there’s so much mid-range torque, but there’s also no drop-off; it makes power straight to redline. My only complaint was the car’s lack of power steering. Though, I’ve been told that retaining power steering is a simple task.

Combine turbo power with a smooth torque curve, and oem reliability, for less than the cost of most turbo kits, and this is what you get. I can’t praise this kit enough — it’s a brilliant idea.

Wanna build your own? Checkout MT's dedicated Ecotec Swap site here.

Edit: To be specific, MT has been using the LE5 from the Chevrolet Cobalt, Saturn Sky, Pontiac Solstice and others.

Update:

After releasing our last article regarding MT Motorsport’s Ecotec swap, the response has been mainly:

“Yeah, 200 whp, that’s great. What about more?”

Now, I stand behind the statement that 200 whp/200 wtq in a 2300 lb car is plenty. However, if you want more, there are options. The 2.4L Ecotec is supposedly reliable with around 350 whp on stock internals. As for making that sort of power, the 2005-2007 Chevrolet Cobalt SS’ supercharger, unfortunately, does not fit in the Miata’s engine bay. You could, use the factory turbo from a 2008-2010 Cobalt SS with some modifications, which judging by a quick Ebay search will run you around $1000. Any other aftermarket turbo kit designed for use with the LE5 engine will work. Beware, you’re venturing into unknown territory. MT Motorsports has turbocharged plenty of Ecotec engines in their factory setting. They’ve never turbocharged an Ecotec Miata, so things may not be as simple as they seem.

Your biggest challenge when trying to extract more power from an Ecotec Miata has nothing to do with the engine whatsoever, it’s the Miata’s fragile transmission. MT has found the Miata’s five-speed to be good to around 250 whp. Past that and it begins to pull itself apart. The six-speed that came as an option on many NB Miatas is apparently good till around 300 whp, which is enough for a conservative turbo build. More power than that and you’ll need to source a transmission from a Pontiac Solstice or a Saturn Sky, though it’s up to you to fabricate your own custom driveshaft. 

That all said and done, you’re still limited to 350 whp by the engine itself. 

I’m a firm believer that the beauty of this swap is its price and simplicity. If you’re looking for massive reliable power, the LS swap is probably still a better bet, despite is being dramatically more expensive.