Mazda MX5 Miata NC 2006-2015 Essential Mods

Many people buy cars and never consider modifying them. You don’t need to mod a car to be a true car enthusiast but most cars do have something or other that can be improved. For Miata fans, we’re focusing this article on the Mazda MX-5 Miata NC 2006-2015.

The NC Mazda MX-5 Miata, or 3rd generation (MkIII) produced between 2006-2015, has been around long enough for owners to have truly uncovered the bare essential modifications this car needs.

In this feature we’re not going to look into heaving modding like adding a turbo or a supercharger. This article is focused exclusively on the bare essential mods that will take the Mazda MX-5 Miata NC from good to great. The information in this article comes from more than a year of research and lots of discussions with hardcore Miata enthusiasts. The personal research done on this car is so vast that oftentimes we can differentiate between something as simple as what transmission oil to use – as not all synthetics are created equal – and not all of them yield the best results.

So here we go. We’ll list them in order to make going through each mod a lot easier and more manageable.

Suspension

Here’s the deal, the stock suspension on the NC Miata is not that great. Sorry, if I burst your bubble if you thought you were paying an extra $550 for the factory suspension package. I do have good news for you though. You do want that package anyway. The money’s in the LSD that’s included with that package, not the suspension itself.

The stock suspension is too soft for anything other than cruising around town or freeway driving. Not to mention the car looks much better lowered at least an inch. But, if you are not the lowering type, performance-wise you would still want to upgrade anyway. The stock NC Miata has a lot of body roll and feels sporty only because it’s a small 2-seater roadster. Otherwise, the body roll, dive under braking and squat under acceleration is reminiscent of a Buick.

Fortunately, correcting the problem is a rather easy affair and can be as expensive as you want it to be. Without counting installation costs, as you might be keen on doing the work yourself, upgrading can cost you as little as $300… or a bit more at $1,200… or you can go all out and spend $3,000. Let me break that down for you in easy-to-swallow bite-size options.

Option 1: The bare minimum – sways. This option involves doing something as simple as only replacing the stock sway bars for a beefier set from Racing Beat, Progress Technology or Flyin’ Miata for example. Switching out the sway bars will correct some of the body roll. A lot of guys are perfectly happy spending less than $300 to upgrade the front and rear sways and they’re done. This will of course only improve the suspension by reducing body roll, but will not improve ride quality, dive or squat. It might make the ride comfort a little worse – performance over comfort. It will also not reduce ride height. You can get a good set of sway bars, front and rear combo for around $300.

Option 2: Add lowering too. This option assumes you’re also doing option 1. Add another $200 and install lowering springs on your stock shocks. This is something that works pretty well with the stock Bilsteins in the NC with Suspension Package. While less than high-performance and ideal, it is quite cheap. We’re talking $500 for reduced body roll and ride height while reusing more of the stocking suspension components – so, less waste.

While this option is far less performance oriented than the higher-end options we will discuss, it’s good enough for some very respectable people. For example, Brian Goodwin from Good-Win-Racing, who’s a Miata guru in San Diego California has a setup of just sways and springs on a his 2012 MX-5 GT PRHT. This is a guy who has many Miatas, and runs Ohlins on some of his track cars. If he reckons this simple setup is good enough on a DD, that’s a lot to say. We recommend the Progress springs if you are going this route. Note however, the suspension geometry is a little different between the NC1 (2006-2008) and NC2 (2009+) – this is specially important for the heavier PRHT cars. If you choose the wrong springs you might end up with reverse-rake (front higher than back). Luckily, this problem was discovered a while ago and Progress Technologies designed different springs for both models. I claim part of the fame for the recommendation of that setup to Goodwin Racing, although officially somebody else beat me to it.

There is more information on the development of the NC2 Progress springs on this page of this thread. Note of caution, you can easily be lost for days reading that thread and then turn around and spend a crapload of money.

Option 3: Sway, shock and spring upgrade. I believe this to be the best value option… the one that offers the best bang for your buck. It’s not as cheap as just doing springs and sways, but it offers the biggest improvement over stock shy of spending $2,000+ on a good set of coil-overs. This option involves upgrading your anti-sway bars with a set of Progress Technologies, Flyin’ Miata or Racing Beat sways, and choosing a spring and shock absorber combo. Some popular options include our preferred choice of Progress Springs with Koni Adjustable Sport Shocks. This option will set you back around $1,200 for the full combo of sways, shocks and springs. Another popular combo is using Flyin’ Miata springs with Tokico HTS adjustable shocks. Flyin’ Miata even has various level packages with and without sways. These packages range from $729 to $1,099. This will save you a tad bit over our preferred Racing Beat / Progress Technologies / Koni option.

You can find all the options for our recommended Progress Technologies springs, Koni shocks and Racing Beat or Progress sways on Good Win Racing’s NC Suspension catalog.

Option 4: Coilovers. This would be the daddy of all suspension upgrades, but of course it depends if you buy quality or not. It used to be that coilovers meant expensive-quality, but nowadays there are cheap crappy sets out there selling for less than a decent set of springs and shocks. Unless ride height-adjustability is absolutely essential for you, it’s generally better to invest in a good spring/shock combo, like Progress/Koni than to spend the same amount of money in what would equate to a lower end set of coilovers.

Ride height adjustability aside, you’re looking to start at around $1,200 for a nice set of H&R Coilovers for MX-5 Miata or $1,500 for Tein Flex coilovers. But, to really get going on some really good coilovers you need to look at $2,200 for a set of KW Suspension Variant 3, $2,200 Fat Cat Motorsports Coilovers, $2,400 Bilstein PSS10 or all the way to $2,600 for the very amazing Ohlins Road and Track DFV MX-5 Miata coilovers. Of course there are other higher-end options like Penske or Motons, but these are usually way too expensive for what most non-racing Miata drivers are looking for.

For coilovers setups, sway bars are very subjective. You need to make sure what coilover setup you’re buying and what you intend to do with the car (DD, canyon carving, autocross or track) and decide on the sways accordingly. Some of these setups are recommended with upgraded sways, some with only an upgrade at the front and some with no sway upgrade at all. So, keep that in mind.

As you can see, you can spend a little or a lot on coilovers and they can truly be the best option for ultimate handling. However, if you simply don’t want to spend that much, you’re better off with a good spring/shock combo than cheapo coilovers. Unless you just want to slam the car and vibrate your teeth out of their sockets. In that case, more power to ya. We respect all aspects of car culture.

If you insist you want ride height adjustment and don’t want to spend a giant wad of cash, I think the best option would be H&R Coilovers. Why? Those are the ones I would buy for my own car if I only wanted to spend around $1,200. Give my friends at Bean Garage a call. They don’t specialize on Miatas, but they do carry H&R and are standup guys. They can order those for you.

Alignment

Once you decide what you’re going to do about your suspension you want to get an alignment. In fact, even if you decide to run the stock suspension into the ground for a few years, you should get an alignment right away. Stock alignments are usually pretty funky and with quite a bit of tolerance. Not to mention, I wouldn’t trust a dealer to do the alignment anyway, so expecting good alignment after buying the car or negotiating it into the deal will likely not yield very good results either.

When I bought my 2011 MX-5 new, it came with a funny alignment and the steering wheel wasn’t even centered. I called the dealer and asked them if they could please align the car as it was “off” and clearly stated the alignment numbers I wanted. To my chagrin, the dealer’s tech told me he couldn’t give me the numbers I wanted and that he could only align it to “spec.” He proceeded to tell me these cars only have camber and toe adjustments and no caster adjustment up front. Something that is clearly wrong and I quickly raised a big red flag. I decided it would be a stupid idea to try and get a free alignment from the dealer and rather pay a proper shop to do the job right.

Alignment numbers can vary so I suggest you do the research. But, I believe these cars like to have a little bit of camber along with the highest caster you can get, for heavier steering and better centering after corners. Guys tracking or auto-crossing their cars like quite a bit of camber, around 1-2 degrees all around and zero toe all around. But if you do a lot of freeway driving, you might want to go easy on the camber and have a tad bit of toe-in in the front to help the car track better on the freeway and not spend your entire commute sawing at the wheel making corrections. If you only drive curvy roads, you’d probably like the responsiveness of zero toe all around. Some auto X only guys like to have a bit of toe-out. But that’s under very specific circumstances and probably won’t apply to you. Actual alignment numbers are a bit beyond the scope of this article, so I’m not going to go much more into that.

Transmission fluid

Yes, believe it or not, this is an essential upgrade for the NC Miata. You might have noticed how notchy and crunchy the NC 6-speed transmission can be. Specially, before it fully warms up. Replacing the transmission fluid will literally make this transmission buttery smooth. Now, if you have a brand new MX-5, this is something you might want to do AFTER the first 10,000 miles. The reason for this is you want to make sure all is well with the tranny from factory. While putting a better fluid in there will generally not void any warranties, it’s better to be safe than sorry. It also makes sense to let the transmission break in with the factory juice. In the rare case there is a problem from factory and your tranny needs repair or replacement, the service department would flush out your new and expensive lube anyway.

So what is it? Well, a couple of guys still argue for Redline, Motul and Amsoil… but literally dozens if not hundreds of NC Miata enthusiasts have confirmed, the miracle juice for the NC 6-speed transmission is… wait for it…

Ford Motorcraft Synthetic MT Oil part number XT-M5-QS.

Consistent seat of the pants tests have been done by plenty of MX-5 NC enthusiasts and they have all confirmed that it is miracle elixir and outperforms Redline MT-90 in terms of feel. I have driven a stock NC 6-speed back to back with a NC with Motorcraft in the tranny and I can tell you THERE IS A HUGE DIFFERENCE.

Now, the stuff ain’t cheap. You’re looking at roughly $20 a quart and you’ll need 3 of them. Unfortunately, you’ll end up putting away most of the 3rd quart as the Mazda MX-5 transmission capacity is 2.2 quarts. Some claim they’ve gotten up to the fill line by the end of the 2nd quart, but why take the chance and end up needing to go back to the shop to get the 3rd quart when your car in on jack stands?

This one’s hard to find. Regular auto parts don’t sell it so you might have to go straight to a local Ford dealer. Locally, those are like Starbucks with one on every corner. Before you go anywhere, I did find it on Amazon. Below is a link to it:

To do the job right, you’ll also need to buy some new crush washers for the transmission plugs from your local Mazda dealer. They’re cheap, so don’t worry.

Another good thing to do while you’re under there is change the differential fluid. Differential fluid actually breaks down and burns up faster than transmission fluid, yet because failures are rare, it’s not replaced often enough. If you do the change you’ll probably notice how dark, awful and smelly it gets after just 15,000 miles. For this you don’t need Motorcraft, but a good synthetic from Mobil 1, Redline or Amsoil in the proper viscosity will always be best. Check your manual. However, for quick reference SAE 90 or 75W 90 GL-5 is recommend. There has been some debate on GL4 vs GL5 gear oil, but the common consensus on the forums is to use GL-5 in the Miata limited-slip differential. Notice that the owner’s manual recommends changing the differential oil every 30,000 miles, but honestly, the stuff gets so filthy I’d rather do it every 15,000 miles.

Any question as to whether or not the Motorcraft lube is awesome? Check out this thread.

For info on how to change the transmission oil in a Mazda MX-5 Miata read this.

Horn

Props to Brandon Yang for reminding me of this one. I’m guilty for not having done this mod yet, but I will. The fact of the matter is, unless you are a Miata fan, this car is rather invisible. Even in bright red, it is invisible to dull people, large soccer moms in large SUVs and reckless dumbasses in pickup trucks. Because of this, the stock horn that sounds like a dolphin with a hernia being squeezed is less than adequate. Face it, flipping a reckless driver is not going to save you from an accident. You want something that will tell the mindless driver, “Hey, @%#$%&#! I’m here!

That’s where the Stebel Nautilus Air Horn comes in. It’s designed for motorcycles, so it’ll fit in your MX-5 just fine with a little bit of work. More importantly, it’s frigging loud and sounds like a Peterbilt at a ball game. So, next time some blind puppet is close to hitting you on the freeway, blowing the Nautilus will scare the careless driver straight into a different car.

You can buy the Stebel Nautilus Air Horn using the link below. While you’re there, pick up the Ford Motorcraft XT-M5-QS transmission fluid as well:

Exhaust

You could argue that an exhaust upgrade is not a definite necessity in the NC, that’s kind of why I left this for the end. On other hand, the enhanced induction sound when revving the Miata engine is quite nice, but it sort of needs to be balanced a little bit better with the exhaust noise which is really quiet in comparison. I’m not talking about going all ricer-fart-can loud, just mildly more muscular. While a header and mid-pipe do offer quite a bit of power gains and cool noises, a full exhaust is really not an absolute necessity. Plus, you’d have problems to deal with if you need CARB-approved parts. So, for the necessary mods we’ll stick with an axle-back only exhaust… or muffler for short.

A slightly higher flow muffler will spice up the exhaust note a bit even if the power gains are minimal at best. This will make it so that the exhaust sound matches the induction noise somewhat. Additionally, the transmission in the NC can be a little noisy with considerable gear mesh rumble and a slightly louder exhaust can drown out those pesky noises.

It’s options-galore for exhausts in the 2006-2013 Mazda MX-5 Miata, so do your research and have fun. The most popular options are those that stick with the stock 2-outlet configuration such as the Goodwin Roadster Sport Q and Flyin’ Miata Stainless Steel Exhaust. These are very popular because they look great, sound good and are relatively inexpensive. Another good one is the Mazdaspeed Miata Exhaust for the NC 2006+ MX-5. This one’s claimed to be one of the best sounding exhausts for the NC, but it’s expensive at almost twice the price of the Flyin’ Miata unit. It’s also quite a bit louder but should still keep you at streetable sounds levels.

For a single outlet exhaust, I’ve driven an NC with the Roadsport Street Single and really liked it. It’s about 30-45% louder than stock but at only 12 pounds it does offer quite a bit of weight reduction over the stock 26-pound unit. In comparison, the Roadstersport Q is about 10-15% louder than stock and the regular Roadstersport II is about 15-25% louder than stock. Although a bit loud, the Roadstersport single is not overly drony or unbearable. It’s actually quite fun. But if you are ever considering any other exhaust mods or even forced induction in the future, go with the quieter options. Anything else might get too loud for the streets and some track events with noise level limits. For that reason, I won’t even mention Goodwin’s Roadstersport race at only 7 pounds because that one’s up there near 88 decibels. I guess I just did.

Here is a link that lists all the Goodwin Roadstersport mufflers mentioned in this article and offerings from Racing Beat, Borla, Enthuza and Magnaflow: Mazda MX-5 Mufflers.

Here is a link to the very popular Flyin’ Miata Stainless Steel Dual Exhaust for NC.

Tires

Wait! I left tires for last, not exhaust. Why? Well, some people argue that the stock tires suck because either they are run-flats (on the GT), in which case I agree, or all the other ones are not grippy enough. For street driving, screw it, the stock tires are fine until you burn through them, then get something better. Tires are consumables and unless you’re looking to get the best times at your local autocross or track, you’ll be fine with the stock rubber for a while. However, when it’s time to replace them, THEN upgrade. There are much better options than buying the stockies again.

I know a guy running a 2012 Special Edition GT PRHT MX-5 in SCCA and Porsche Club Auto X with stock rubber and doing fine. I also know a guy with a 2013 Club Edition MX-5 who decided he would rather change the stock tires for Michelin Pilot Super Sport in 225 instead of the stock 205 and install them on the stock wheels. I actually drove that car and it’s pretty awesomely grippy. But that also has a lot to do with the amazing Ohlins DFV suspension on the car. My vote goes towards saving some money and keeping the stock tires at least for half their life.

That said, I’m not going to argue with the folks that say that the best improvement you can make to a car is tires. I’m not going to argue, because they are right. I just hate wasting money if my stock tires are like new. But, for performance the Michelin Pilot Super Sports are hard to beat.

Stock tire size for the NC Mk3 MX-5 Miata is 205/45/R17 – For the Michelin Pilot Super Sport tires I would recommend 215/45/R17. Although, like I said above, 225/45/R17 is possible, but at that point you’ll end up with slightly more diameter. I also know that with further modifications (possible fender rolling) you could fit 235’s under there, but I wouldn’t take it that far. Most of the people going that wide are doing it for competitive purposes such as track or autocross. For a street NC Miata, Michelin Pilot Super Sport in 215/45/R17 would be ideal.

Conclusion

That’s pretty much it. While there are an infinite number of things you can do to the NC Mazda MX-5 Miata, the things outlined in this article are what the folks at RallyWays and many of our friends consider to be the absolute necessity for MX-5 NC owners. Oftentimes people buy cars without doing enough research, if you’re all the way down here reading this feature you’re obviously not one of those people.

When I was doing my research before I bought my NC I was weighing the odds between a Porsche Boxster, Evo X, Corvette and Miata. With each of those cars I was also counting the expenses of necessary mods to make the cars be what they should be. It’s a cost you need to factor into your decision-making. You don’t “have” to do these mods, but owning a car like this and not doing them is bit of a loss and you wouldn’t be truly making use of the whole potential for enjoyment.

Share this resource article with your friends and other MX-5 enthusiasts. I will continue updating it over time as need be when newer and cooler products continue to evolve as the NC MX-5 Miata matures and ages. So again, save the link for future reference and share it.

*Disclaimer – The recommendations made in this article are based on many hours of research and lots of experience. These recommendations are also encouraged by the opinions of many Miata enthusiasts based on experience and best practices. While we believe these mods to be very positive in the improvement of the Mazda MX-5, we cannot guarantee your results. Also, these are serious modifications. If you are not qualified to do them safely, you should hire a professional to do them for you. This is for your present and future safety as well as those around you. If you decide to take on any of these recommendations, you should continue to do more research and become better informed. You proceed at your own risk and responsibility. We cannot stress this enough. We cannot state that any of these modifications will not affect your vehicle warranty, so proceed with caution.

Done with the warning bits. Enjoy.