Fun, chuckable, cheap to run, and even cheaper to maintain. This is what made the Mazda MX-5 the best-selling two-seater roadster ever. The car is built around a rock-solid chassis, ridiculously low weight, and a choice of several powertrains to provide unrivalled motoring thrills for the money. But if you’re picky about power and torque curves, especially in the early NA and NB models with the 1.6 and 1.8-litre engines, there are hundreds of additions to get that sorted.
Tuning your Miata is done in stages. Subtle gains that include more responsive throttle, quicker acceleration, and improved drivability are achieved with the simple remapping of your ECU’s software. This changes things like the fueling and timing to belt out a few more horses, have power spread across a wider rev range, and adjust redlines for extra push.
And it’s a simple, cost-effective way to get the most out of the smaller engines without having to spend on extra parts. This is what most tuners consider Stage 1 tuning. Others will make changes to the air intake and exhausts to balance things out, before going on to more serious mods in subsequent tuning stages.
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The basics of ECU tuning
ECU tuning or remapping involves installing new ‘maps’, essentially the collection of engine and vehicle parameters that define how the car drives. Manufacturers won’t give you the car’s full potential for the simple reason that they balance longevity, fuel use, and performance to meet most drivers needs and comply with regulations. The 114 bhp in the 1.6 and 138 bhp in the 1.8 might be enough, considering how light the car is, but an aftermarket MX5 ECU remap can extract more performance. The only catch is that the early NA and NB cars had ECUs that weren’t remappable, but cheap pre-programmed options are easy to come by.
ECUs control fueling, engine timing, and emissions levels. Slight changes can make substantial power gains, which you’ll appreciate in the lower-powered MX-5 engines. You’ll see more torque available lower down, so more pulling power from a standstill, quicker acceleration made possible with revs holding higher, and extended redlines so the car never runs out of puff even with the gas pedal floored. A decent result from half an hour’s work.
The same process is required, albeit with modified maps and EC tunes, when adding performance parts. While you want the extra power for pure driving fun, you also want the car to last. Maps balance out the variables with each new addition, so the car not only performs at its best but will do so for years to come.
Remapping a mazda miata
The NC and current ND cars can be remapped without having to change the whole ECU. The cars are connected to a computer via the OBDII port; the factory maps are first scanned, then erased, and the new software is downloaded. In most cases, owners can also see previous changes ( in maps or added parts), and revert to factory settings.
The thing here is going with trusted tuning brands, as any dodgy software that’s not thought out to the last detail can do more harm than good. The whole process lasts less than an hour and will depend on your choice of tune. Like tuning in general, ECU remaps are done in stages (1–3), with incremental improvements the higher you go.
For the NA and NB models, you’ll be looking at swathes of aftermarket ECUs with the appropriate wiring and mounting hardware. These are slightly more costly than a basic ECU remap on existing NC and ND Miatas, but you won’t miss out on any of the performance benefits. Keep in mind that there are different versions for different markets. Cars sold in the UK won’t work with ECUs specific for US and Japanese markets (considering the many Eunos imports).
Pros of an ECU Tune
I’ve touched on the pros of remaps and how they can transform an older Miata and breed a new motoring life. But let’s get all the pros in one place and see whether ECU tuning has any downsides.
Increased torque and power
Depending on the remap, or ECU, you choose, cars can increase power numbers by up to 15 percent. For the smaller displacement engines, this means an additional 20–30 horsepower and roughly 20–25 Nm of torque. If you’re tuning a turbo Miata (either with the MPS engine or an aftermarket turbo conversion), this can exceed 50 percent over stock. Much of the added power is due to modifying air and fuel ratios at varying engine speeds and more efficient timing.
Power curves can also be changed, so you get improved throttle response, and the engine extracts the last drops of power at higher revs before gear changes follow. In short, the added power translates to better acceleration, using lower gears for maximum power efficiency, and more leeway when pushing the engine harder.
Improved efficiency and lower fuel use
Increased combustion efficiency means less fuel spent to get the quoted power figures and bring your Miata up to speed. An ECU tune can specifically be done to lower fuel use across defined engine speeds without affecting power delivery. This has been done in standard diesel engines for years.
The benefit for the Miata is that while there’s more power on tap, the engine will actually be sipping less fuel. Air and fuel ratios are brought to an optimum, so there’s no risk of related fueling issues, such as carbonisation in older cars, or billowing smoke in differing colours from the exhaust.
Fix previous engine and vehicle issues
Older cars may have enduring issues that haven’t been resolved. The car can underperform due to problems like intermittent engine knock, overly long throttle lag, incorrect temperature settings in thermostats, fans, and sensors, and more. This is often more due to failures within the ECU and the maps, than the parts themselves. A remapped ECU can delete these problems and prevent them from throwing up the check engine light in the dash until there is a real issue at hand. With that said, it also means engine and part longevity is increased.
Now for the cons. The only thing worth mentioning is finding a decent Mazda tuning shop and ensuring that the software or replacement ECU is compatible with your Miata in terms of model variations and production year.
How do I follow up on a remapped Miata?
Depending on what tuners define as Stage 1 tuning, an ECU remap or replacement can also be followed up with changes to the stock air intake, swapping (and relocating) the factory airboxes, filters, and piping for cooler air. This vastly improves combustion and means more power without having to stress the engine.
To add to the efficiency equation, you’ll also be looking at an exhaust upgrade, either as a less costly axle-back system to remove gas flow restrictions and improve the exhaust sound, or as cat-back or header back variants that add a few more horses and torque to the gains you’re already seeing with the ECU tune. This sets the foundation for more serious upgrades, such as high-flow injectors or cold spark plugs to maintain better air and fuel ratios and higher temperatures, and the foundation for all the complex work that follows in Stages 2 and 3.
For most NA and NB owners, though, an ECU tune is all it takes to add that little dose of fun, and a bit more drivability to a car that can still hold its own against the newer competition.
