When engineers and designers get bored, they come up with automotive marvels. The Mazda MX-5 is the best-selling 2-seat roadster that you can get your hands on. It’s been around for ages, and only subtly modified from the near-perfect first cars to roll out on the UK market since 1990. And when cars get nicknames like the Miata, you know the love they get from driving enthusiasts.
Though it doesn’t have sheer the bhp numbers of bigger cars, the whole package is lightweight and peppy. It’s sure to get you grinning from ear to ear when you’re driving down backroads, or swerving the back wheels into a spin at the track. The bullet-proof 1.6 and 1.8-litre engines in the first model have made the Miata one of the most modified and tuned cars there is.
And it ticked all the boxes for a little, lively sportscar. It’s rear-wheel drive with good power to weight and enough grip to be planted in a straight line, or thrown into a bend. 115 horses in the smaller 4-cylinder engine weren’t much on paper, but with it, the car could get to 60mph in just a tick shy of 9 seconds. If you wanted more oomph, you’d go with the 1.8 litres. Models that followed refined minor mechanical or electrical issues, and moved with the times. The soft-top roof was shunned (but brought back later), the pop-up headlights replaced and the cute curves turned into muscular edges. More power came from the larger 2.0-litre engine in the third-gen car from 2006, but with more weight. The current model is sold either as a 1.5 litre or 2 litres 2-seater RF hardtop or soft-top convertible.
You don’t need insane power numbers to get you smiling. But with aftermarket parts cheaply and readily available, and easily fitted, you can do better than the officially quoted 0-60 times. Here’s what to look for to get a little more push or better handling:
Exhaust Systems and Parts
By far the most changes are done to the stock exhaust. Newer Miata exhaust parts shed a few pounds and make the car even nimbler. Of course, you get a few more horses, and a raspier exhaust note, something that you can feel and hear with the top down. All cars can be fitted with a range of different exhaust types and parts. The goal here is to get better exhaust flow with straighter, simpler tubing while reducing overall emissions, especially in the first-gen models. Though not a game-changer, you’ll also get better fuel economy.
In older Miatas, the catalytic converter can clog up, effectively choking the engine. You feel this when the pedal is down, and the motor struggling to rev. Cars with higher mileage are also susceptible to blockage. The first-gen Miata came with a bolt-on catalytic converter, so are easier to replace, with subsequent models having the converter welded into the exhaust mid-pipe.
Exhaust Manifolds, Gaskets and Oxygen Sensors
If your car doesn’t pick up speed, while also putting out a weird rumbling sound, there might be leakage from the exhaust manifold. Either it’s cracked or the gaskets are worn. This allows for nasty smells and carbon monoxide to seep into the cabin. Replacement manifolds are an easy fix. If you want more power, say in the 1.6 litres, go for a new performance manifold. It may come at a cost, but the results are definitely there. Gaskets, both inlet and manifold to exhaust gaskets are cheap to replace. The gen-3 NC Miata has a built-in oxygen sensor that monitors exhaust flow. You can also install this in the previous models, though an ECU retune might also be needed.
Mufflers don’t affect speed as they do the exhaust sound. If you want to commit the sin of deadening the engines sound, get a muffler with an inbuilt resonator. Or do a muffler delete, and put on a straight tube for the loudest exhaust note. Combined parts, including new exhaust tips, are found in axle-back Miata exhausts. If you want a sportier look, go for dual exhaust tips in chrome coating.
Cat-back and Complete Exhausts
The best performance gains are from bigger tubing in cat-back or complete replacement Miata exhausts. The cat-back exhaust is a good upgrade with wider midsections, but to get the engine breathing as new a complete header back exhaust changes everything from the exhaust manifold, through to the converter, muffler and exhaust tips. Kits are supplied will all the needed parts for mounting. If you’ve put in a turbo, then a turbo-back exhaust is what you should buy. All aftermarket exhausts comply with current UK emissions regulations.
Exhausts are best paired with new air intake induction systems. Compatible kits for the 1.6 and 1.8-litre engines in the gen-1 NA and gen-2 NB Miata are easy and cheap to find.
Check the rotors, callipers and pads in cars with over 100K miles on the odo. With better brakes, you can keep more speed into corners, and have shorter braking distances. You get both fun and safety in the same package. Replacement parts are cheap unless you get branded performance brakes. Brakes are changed in front and back pairs, so factor in the labour costs as well. Also, check for any issues in the ABS.
Suspension and Steering
Miatas use traditional springs and shocks. The stock springs should be fine even in older cars, but shocks may need replacing, especially if you feel every rut or hole in the road. For the best control and handling, packaged performance suspension kits for all four wheels have adjustable damping and rebound settings. Inspect for any damage to suspension bushings, track rods, ball joints and upper and lower suspension arms. If the steering is stiff, replace the pump and power steering pressure pipe.
Turbos and Engine Swaps
To get the biggest bump in performance, install a turbo. You’ll also need to change the manifold, exhaust, clutch and flywheel and put in a bigger radiator to cope with the extra heat. The best engine here is the 1.6 litre. Or you can swap out the whole engine for something like the 2.3-litre turbo in the Mazda 3 MPS. It’s got over twice the power and torque. The engine bay can even be modified to fit a huge LS 6.2 litre V8 nicked from the Corvette. Just remember to also swap out the brakes for something bigger and with more bite, and get grippier tyres.
Buying Miata Parts
Miata parts are sold through numerous online retailers. If you need a specific part, like a tailored Miata exhaust, your best bet is garages stocking used MX-5s. Here you can get quotes for any needed replacement parts and labour costs.