Brap To Reality: The Bridgeported 13B MX-5
Where Have I Seen You Before?

If you’re feeling a slight sense of déjà vu, don’t worry, you’re probably not alone.

In fact, anyone who has been visiting the site frequently since, let’s just say, March 2016, is probably familiar at the very least with the exterior of this Rocket Bunny-kitted Mazda MX-5. Due to an unusual set of circumstances, which can basically be summarised as being in the right place at the right time, this became the first Rocket Bunny MX-5 in the world, and as such, gathered quite a lot of attention online.

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Back then, the car was still running its factory 1.6-litre DOHC engine, making approximately 100hp or thereabouts. Fast, it was not.

At the time, its owner, Rick Weldon, told me that he planned to swap a rotary of some description into it. We hear a lot from owners of their ultimate plans for a car, but due to life being what it is, sometimes things just don’t happen, so we always take these aspirations with a pinch of salt.

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Considering what Rick went through, I would have understood if he had given up, but two years after the conversion started, the little Mazda had a lot more brap under the bonnet. It shouldn’t have taken that long really, but the first company to attempt it made a mess of things, and left Rick with an MX-5 and a non-running 13B, which wasted a year.

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Ireland is short of rotary specialists, so despite the country’s love for all things JDM, it’s rare to see any rotaries alive and in the wild, which makes it difficult to find someone trustworthy and reliable to take care of such projects. Luckily, Rick found a safe haven in Darren McNamara’s Group-D (yes, the same D-Mac you’re thinking of, and no, the Audi isn’t finished yet…) who were able to takeover and complete the conversion to the highest of standards.

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The reason why I found myself shooting Rick’s MX-5 on the coldest day in the history of the world, is that it’s for sale at the moment, and I wanted to tell its final story before it eventually disappears away with a new owner. And it will sell, because it’s an absolutely fantastic car.

So, where do we start?

The Same, But Different
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For such a small car there’s quite a lot to get through, but before we go any further I will say that it passes the Speedhunters Overfender Test. That is, it’s not otherwise stock. This has been a bit of a prerequisite for me when shooting these sort of cars over the last couple of years, although I would allow a car which wears the first of each kit an exception of sorts.

Otherwise, I don’t think it’s enough anymore for a car to just look the part – it needs to dance the dance as well.

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As a panel beater and painter by trade, Rick took a lot of care when actually fitting the kit. It wasn’t just fired at the car. The fuel filler cap has been removed and flushed, as have the hardtop mounts and factory side repeaters for a smoother look. The rear diffuser has been removed too, as it would have had to been cut up so much to accommodate the much larger rear silencer that there’d be little left. More on the noise in a bit.

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An area which has been arguably improved is the wheel fitment. There was a lot of time spent on this aspect of the car, but most notably the rear fitment. Previously the Mazda was running a significant amount of negative camber in the rear, which necessitated the addition of spacers to help bring the top of the tyre closer to the lip of the wheel arch. This had the unfortunate effect of the rear wheels looking too far apart when viewed from square-on behind, making the car look a little awkward. With some custom extended front and rear upper arms and larger tyres, Rick was able to dial-out most of the camber, and have the wheels and tyres fill the arches without the need for spacers.

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The wheels are the same Work Meister S1s in 15×9-inch (front) and 15×10-inch (rear) otherwise, with offsets of -28 and -38 front and rear respectively. I think the little bit of extra profile on the tyres (205/50R15 and 225/50R15) makes a noticeable difference, giving the MX-5 a more purposeful stance.

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Yes, the tyres could be wider, but with such a light and small car that’s primary purpose is fun road use, I can appreciate keeping them on the narrower side to allow for a more playful dynamic with a lower breakaway speed. You know, keeping it fun rather than having the car gripped-up to high heavens.

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The bump in tyre profile also helps to subtly raise the Mazda, which is a must for the roads around these parts. It’s still static as it was before, running HSD coilovers.

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While the car was away, Rick picked up another MX-5 to fill the small convertible-shaped hole in his life. This other Mazda’s purpose was to be used as a beater/track car, with some modifications including a Wilwood brake kit for circuit use. Unfortunately, it was stolen one night and later found burnt out. The only parts to survive the fire were the front brakes, which now live on behind the Meister S1s.

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On the inside, a lot is crammed into a relatively small space. There’s a roll bar behind the matching Bride Zeta IIIs mounted on Skid Nation brackets, a Nardi wheel fitted with an NRG snap-off kit, and a Group-D hydraulic handbrake lever.

Mounted neatly on the side of the centre console is a Haltech Elite ECU, with a plethora of vent-mounted gauges to cover your typical temperatures and pressures. Where there might have been an entertainment unit of some kind now resides an electronic water pump controller. Those of you with a keen eye will also have noticed the braided lines running along the passenger-side floor.

Those would be for the custom dry sump and fuel tanks in the boot. As with the rest of the car, there’s a nice amount of consideration and attention to detail with how everything is mounted, including the lightweight dry-cell battery. There’s even a convenient storage tray for a bottle of pre-mixed 2-stroke oil.

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It might have taken the guts of two years to transition from pistons to rotors, but it was well worth the wait.

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Without going full show car levels of tuck, the conversion is about as clean as you could ever want, with the bridgeported 13B sitting extra low in the engine bay thanks to the aforementioned dry sump system.

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Group-D took care of the whole conversion, only outsourcing the engine build to their partners at Hayward Rotary in the UK, who built a very similar 13B for the Need for Speed AE86, albeit without the turbocharger this time around. Instead, there’s an EFI Hardware throttle body setup with four 550cc injectors. There’s also LS coils and the crank angle sensor from an FC RX-7.

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A 12A front cover was used in conjunction with a custom Group-D engine mount, but there are some things missing from the bay. The alternator has been relocated elsewhere and the original mechanical water pump has been deleted, with a Davies-Craig electric pump being used instead.

You’ll also notice the pop-up lights are always up, because the motors have been removed to save weight and tidy the engine bay further. A Driftworks radiator, with stainless pipes, and an external oil cooler kit help to manage temperatures.

While it was a very windy day, I did manage to quickly capture some video to give you an idea of sound, because we all know that’s really why you’re here.

When Rick originally collected the car, it was pretty much straight-piped and was so loud that he would free-wheel it a considerable distance downhill towards his house and push the car into his driveway, so as not to annoy his neighbours. There’s a large silencer now at the back of the car, hence the removal of the diffuser.

It’s still loud, but I would have loved to have heard how rowdy it was beforehand to necessitate that level of caution.

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From a transmission perspective, Group-D used an NA RX-7 5-speed gearbox fitted with an MX-5’s rear casing, and an ACT clutch.

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I’m sure that for so many people, this is the ultimate MX-5/Miata/Eunos Roadster. It has pretty much everything that a diehard Mazda fan would want, but especially the powerplant and accompanying soundtrack.

For Rick, however, his time with the car has come to an end. With a commute to work of just a couple of minutes, the MX-5 doesn’t get used anywhere near as often as it should. It’s small, low, stiff, impractical and horrendous on fuel. It needs to be carefully maintained and just cannot perform short journeys.

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While Rick did manage to build the car he always wanted, I guess the reality of living with it doesn’t make much sense. I have huge respect for him in getting the car done, but still being able to acknowledge that it would serve someone else better, as opposed to being parked up and not being used.

He did say though that when driving it, all of its shortcomings disappear. It’s amazing the things you would justify for a 9,000+rpm soundtrack.

Paddy McGrath
Instagram: pmcgphotos
Twitter: pmcgphotos

Cutting Room Floor

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paddy, your work is a work of art! awesome story!


Thank you, mate :)


I wonder if Rick would've have held on to the car if it wasn't so extreme.

My 1st generation RX-7 goes to the track, but 95% of the time it's on the street so I didn't go crazy on suspension and kept the porting and exhaust mild.


He has another MX-5 which is near stock, and he said he likes that as he can just jump in and drive. He's still tempted to hold onto it, as when he does get around to driving it properly, it's really something special.


I saw this for sale recently and I can tell you it was soooo hard to resist making an offer xD


ohp there goes gravity


Sick! Love it! And those brap-brap exhaust notes!


One of the coolest NA I've ever seen!


The original set of images when it first debuted are amongst my most stolen of all time XD It's a popular car.


I'm sure rotary fanboys will go crazy over this 13b swap MX-5
It's an awesome build for sure!


Imagine if Mazda made a rotary powered Miata
That would be the best sports car ever!


I have seen this car in the flesh and I really fell in love with it. The build just makes you believe the 13B and MX-5 really belong together. Nice feature, sad for the dude to have to let a thing like this go


If it sells, I hope it doesn't vanish into the ether and that it's next owner gets it out and uses it. It's a riot of car.


All I can hear is Eminem

'Brap to reality, oh there goes gravity...'


I was thinking more Soul II Soul, but that's probably my age showing.


Hahaha no I get that one too! Brap to life!


I hope he doesn't track on *that* exact wheel/tyre set up.


He's entitled to use whatever he wants, and if he's having fun, who cares?


Ultimate Miata indeed. Hope they make 13B's on new miata's from Factory. Since miata was made for fun driving maybe mazda will someday put that out.


Great write up and great shots Paddy! What do you primarily shoot with if I may ask? I'm always curious what cameras and lenses you use to capture your shots.