Even since the first iteration of the MX-5 back in 1989, the idea of adding power to the light and nimble roadster has been an ongoing conflict. Mazda designed the car to be simple, with low power and weight, and near perfect weight distribution. But does adding a little bit more “go” really detract from the other great characteristics of this little car? The recipe is pretty perfect, with great balance, low weight, and power going to the rear wheels, but Mazda seems to think differently.
Fortunately, enthusiasts have been strapping various power adders to MX-5s for decades now, and the current ND platform is looked at as a perfect base on which to build the perfect sports car. Forced induction is one of the most reliable and cost effective ways to bump up horsepower numbers, and here are a few things to consider if you’re thinking about giving your ND some extra punch.
You should consider a twin-scroll turbo setup
Traditional single-scroll turbochargers are readily available from nearly every reputable turbo manufacturer, but to get the best drivability and usable power, a twin-scroll turbocharger is best. Not only do they reduce lag by helping exhaust gases to flow more efficiently, they also create a better scavenging effect – which uses the low pressure area behind each exhaust pulse to ‘pull’ gases out of the engine, helping it breathe easier.
Mazda put a lot of work into reducing engine back pressure, and by using a twin-scroll turbocharger, you retain as much of that as possible.
A well-executed turbo setup does not feel turbocharged
One of the best things about how a MX-5 drives is how it delivers its power. Because the factory engine is normally aspirated, the car feels very responsive and crisp. Turbocharger setups have a reputation for feeling “laggy” or non-linear when the boost builds, but by pairing the right size turbocharger to the car, you can make it so that the car drives like its normally aspirated, but with the added power of forced induction.
When combined with some choice chasses upgrades, it takes everything that the MX-5 is all about, and amplifies it proportionally. When set up properly, the ND does not feel hindered by its additional power.
Go for a turbocharger instead of a supercharger
One of the main questions people ask when adding forced induction to a car is whether to go with a turbocharger or a supercharger. For the ND, a turbo makes much more sense. Superchargers come with inherently high parasitic losses because of the power required to drive the belt that in turn spins the supercharger, therefore requiring significantly more boost to create usable power gains. That increase in boost can lead to knock and pre-detonation because of the ND’s SkyActiv-G engine which uses a high compression ratio. For safe, reliable, efficient power, a turbocharger is by far the best option.
Power limitations of the stock driveline
The ND is a well-engineered vehicle, but everything has a weak link when adding power. A good rule of thumb to follow is that if you plan on exceeding 240 crank horsepower, you should consider building the engine with stronger connecting rods and pistons, and if you plan on exceeding 300 crank horsepower, a stronger transmission will be required.
Since the first units rolled off the assembly line back in 1989, the Mazda MX-5 Miata has earned a reputation as being one of the most pure, exciting, and fun driver’s cars in the world. They have dominated race tracks around the world, and their simplistic nature makes them a pleasure to work on. By strapping a turbocharger and some related components to a brand new ND, you’re left with one serious little roadster that is ready to tear up the track.