Deadline Set: Taking An RX-8 From Stock To SEMA
Deadline Set

Those familiar with Speedhunters, and the annual SEMA Show in Las Vegas, might recognise the name Jonny Grunwald.

Jonny was formerly Bulletproof Automotive‘s project manager and has a string of project cars and builds under his belt, including his own personal FD3S (the white one), so he’s definitely got the right credentials when it comes to building a world-class SEMA showpiece.


The seed for this built-for-SEMA RX-8 was actually planted by none other than notable rotary headcase Mad Mike Whiddett. It was during an encounter with Mike at Fuji Speedway in Japan that Jonny first saw then-unreleased renderings of Miura-san’s upcoming Pandem RX-8 kit, which the sideways-happy Kiwi had a hand in helping design and would be applying to his latest BADBUL drift build.


While impressed, Jonny thought nothing more of it, until just five weeks prior to SEMA 2017 when he was offered the opportunity to build a car on behalf of TRA Kyoto/Pancross and Toyo Tires for the show.


Before he could even think about saying no – less than 72 hours later, in fact – he’d sourced a car and it was being stripped down ready for the build. Work began on the engine build first, before the team started on the body.


Flying back to Los Angeles fresh from TCP Magic’s Formula Drift Japan Okuibuki win, Jonny and the Lucky 7 Racing team began work on the RX-8 with its stock exterior before the kit would arrive less than two weeks before SEMA. The kit that Jonny last saw in the renders was soon being unloaded from boxes at Auto Explosion Body Shop in LA, where the team began cutting and fitting it to the Mazda.


The exaggerated overfenders add substantial width to the RX-8’s comparatively understated design, seemingly swooping and flowing around the wheels.


I’m usually not the biggest fan of this style of kit, but on certain chassis it works better than others. In my opinion, the RX-8 is definitely one of those chassis.


The kit follows the familiar lines of Miura-san’s previous work, dipping in sharply at the bottom of the fenders. The addition of alloy canards on the front bumper and side skirts helps this design feature integrate better, I feel.


As is often the case, the hardware and lines have been left exposed, creating a clear distinction between OEM and aftermarket.


Jonny also opted for an aggressive RE Amemiya hood complete with RE Amemiya carbon hood vents.


RE Amemiya also supplied the aftermarket front grille and carbon fibre front bumper garnishes, which complements the Pandem kit’s aggressive front lip nicely.

Almost There

One element that Jonny opted to change about the Pandem kit was the rear wing stays, choosing to have them redesigned slightly taller, and cut in titanium. In fact, Jonny actually remade all of the aluminium aero devices on the front bumper, rear quarters and wing end plates from titanium, but not everything made it onto the car.


“We had to wait until the aero arrived from Japan,” Jonny says. “It was just nine days before SEMA – we then scanned, redesigned them in CAD, water-jet cut the titanium, and then burned them by hand. The amount of time and labour that went into these details were insane, only for them not to be used except the lengthened and redesigned wing stands. They get hate, but I love them and smile because of how much work went into that detail.”


Once finished, the bodywork was coated in BASF RM Mineral White Metallic paint, with contrasting black sponsor graphics.


When it came to setting the Mazda down to ground, Stance Suspension XR1 coilovers complete with an air cup kit were used. P2M adjustable control arms all around allow for fine-tuning of stance and alignment.


A set of bronze RAYS Volk Racing TE37V Mark IIs measuring 18×10.5-inch -25 up front and 18×12-inch -33 adorn the four corners, mounted with Thunderbolt titanium lug nuts.


A Brembo Gran Turismo big brake kit peeks out from behind the recessed spokes.


Inside the cabin, the quality of parts, fit and finish is as high as outside. A pair of carbon-shell Bride Vorga Limited Japan Edition seats are paired with Takata Racing 4-point harnesses, surrounded by an Autopower Industries roll cage.

The immediate controls are a Personal steering wheel mated to a Works Bell quick-release for ease of entry and exit. The manual box is stirred with a Tommykaira x Rowen shift knob, whilst a trio of Defi gauges allow for close monitoring or boost, oil and water temperature.

Cutting It Close

Whatever your feelings towards Miura-san’s exterior creations, perhaps the real focus point, and attention, towards this build should be what lies under the bonnet. See, although there’s hardly a generation of RX that’s especially well-known for long-term reliability, the RX-8’s Renesis engine gets even more of a bad rap.


While many would have been tempted to swap in the tuneable 13B-REW, or even a – gasp – 2JZ or LS motor, Jonny decided to do something that not many have done by turbocharging the stock Renesis II motor. What’s more, with the deadline for SEMA looming ever closer, he had just two weeks to do so.


He enrolled the help of Turblown Engineering in Minnesota, who had previous experience of earlier model RX-8s, to get the job done. Turblown created a custom manifold for a BorgWarner EFR 9174 turbo, whilst also supplying one of their oil catch cans and a 10mm engine stud kit.


Meanwhile, back at Lucky 7 in LA, the team raced to create the fuel system needed to persuade the charged Renesis motor to make all the right noises. An Aftermarket Industries SP1000 surge tank, single 300lph in-tank and two Walbro 450lph external fuel pumps, Turbosmart FPR 2000 along with a custom fuel rail and four ID1750x injectors all join forces to ensure that minimal distance is travelled, but maximum fun is had, between fuel stops.


Lucky 7 also created the custom wiring harness to retain all OEM functions whilst making the motor and accessories play nicely with an Adaptronic M2000 ECU.


Once the manifold and turbo was united with the motor, Lucky 7 then went about fabricating all of the pipework to connect up the custom Treadstone Performance front-mount intercooler.


A HKS Hi-Power exhaust ensures that sufficient whistles, pops, bangs and brap-braps are shared with those in the immediate vicinity.


Drivetrain upgrades in the form of a SPEC Stage 3+ clutch and aluminium flywheel, along with an OS Giken 1.5-way LSD were added too.


I should mention that, whilst doing all of this, and with a firm deadline not far away, Lucky 7 also built up a spare, somewhat experimental, bridgeported Renesis II motor, complete with Goopy Performance 2mm oversized apex seals and Phenix Industries hardware. I guess to itch that ‘what if’ that was tickling away at the back of their minds.


The original stock – but now turbocharged – engine, was dyno tuned in LA with remote assistance from Elliot White of Adaptronic over in Minnesota with on-hand assistance of Garage Life Tuning. The team completed over 100 dyno pulls over the course of 24 hours in perfecting and stress-testing the motor. The result was a not-shabby 408whp and 335wtq at 19psi on E85 fuel, which is the best results Jonny has heard of from the OEM Renesis II internals.


With all of that hard work in the bag and running well, you’d have thought the engine part of the build done. But with 48 hours to spare before SEMA load out, Jonny decided to roll the dice and drop in the experimental bridgeport engine. Elliot White took an overnight flight to Los Angeles from Minnesota to make sure the car could successfully run at the show.


Jonny tells me that bridgeporting the Renesis engine is a point of contention amongst the RX-8 community, but with around 1,000 miles now on the experimental motor they are ready to start dyno testing. Estimates are in the 450whp range at the same boost pressure. “It’s a much more relaxing and comfortable ride in-contrast to the time attack-inspired RX-7,” Jonny tells me. “I haven’t had air conditioning for the past decade! Since this is a really crazy, but street-oriented build, I just want to enjoy it as much as possible by going to as many events as I can, and supporting our local rotary community.”

Words by Jordan Butters
Instagram: jordanbutters

Photos by Louis Yio
Instagram: lusciousy

Jonny would like to thank: TRA Kyoto/Pancross, Toyo Tires, RAYS, Lucky 7 Racing, Turblown, Garage Life Tuning, Autopower, Adaptronic, Stance Suspension, Brembo, Bride, Auto Explosion Body Shop, Fox Marketing, Takata, Aftermarket Industries, Speedster Oil, Derek Chan, Mad Mike, Taisuke Kawato, and Speedhunters.

Cutting Room Floor


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that's a lotta mods!


kit makes door not open?


A few of the photos shows the cuts made into the kit so the doors can open. xD


Yeah, can anybody explain? Or is there a way to somehow make it works?


Hey White 86,
The body kit is designed to have the ability to open the rear doors if necessary by removing 7-8 allen bolts on each side (takes about 2 minutes). The body kit is so wide that if you attempted to open the door without removing this panel it would make contact. But if you have a cage most people aren't throwing anything in the rear seat thats large enough or doing anything necessary to open the rear. I won't be moving out of my apartment using the RX8 haha.

By the way, I hope you enjoyed the Bulletproof 86 feature previously featured on SH.

Jay Soh Tsu Chung

So beautiful!


damn jonny making RX8 look dope AF. TE's on all the things! :o


Great kit, and I really like the look of the rx8! Is it just me or is the fitment on the front a little funky looking? Hard to tell but in some pictures it looked like it could use some spacers


Hey Dillon,
I'm a big function over form guy. We did an aggressive alignment like my FD3S and the RX8 wheel setup is the largest Rays Wheels / Volk Racing forged offering with the TE37v Mark II at 18x10.5-25 and 18x12 -33 I can camber it out to 0 and poke or go with a less aggressive camber profile to make it look "hella flush" but drivability is everything to me. This kit was also originally designed for a tube chassis race car and a lot of details/work needs to be made to perfect it for daily street use. I think the coolest thing about Rocket Bunny/Pandem is the diverse setups and styles people go for pending on their intended use.


So they didn't have time for fitting thee titanium body kit but had time to make 2 engines?!!!! that's little bit confusing, maybe the parts availability was the biggest difference.
A very nice build specially that it's done in a very limited time and it could be the best RX8 till now. The only problem it that the RX8 can't surpass the RX7 design, hope Mazda guys are working on a new masterpiece.


Hey Ishac,
It just came down to personal preference. I can swap out the additional titanium aero bits whenever I feel like a different look or for an upcoming event. Honestly, I already have a few carbon fiber revisions working in the back of my head but for now I'd just like to enjoy it. Hope you have time to check out my RX7 also featured on SH.


Thanks for your reply and it's good to know that it's evolving, even if the RX7 is more lovely the RX8 must take it's fair bit. So aesthetic wise is covered, hope you reach your goals with the bridgeported engine.
I've already checked your RX7 featured before (never miss articles like these) and you have split my heart in half both approaches are beautiful.


Can you bring this to DGRR

Love to see it in person in 2 weeks.


Hey Tim,
It's a dream to hit DGRR to support an inspiration and long time friend Phil. He's got an arsenal of amazing cars and new ones in the works. Hopefully I'll make it out there with both cars from LA one day.


Is it typical to oversize turbochargers that much for rotary engines? for a car that's going to be in the 400-500whp range I would of thought an efr7670 or even 7163 would easily support the airflow numbers for that power. While also bringing a lower boost threshold, wider powerband, and quicker response.


Rotaries are less efficient than piston engines at producing power compared to the amount of air that flows through them. Luckily, they flow large volumes of air very quickly, so despite needing larger turbos to create a given power, they also spool larger turbos much more quickly.


Yes it is typical. Rotaries need bigger turbos.


I'm no rotary genius but my understanding would be to compensate for the longer, higher powerband


Ditch the renesis!


Appreciate the tons of hard work that went into this build but I'm not feeling the overall look - it somehow seem like a lot of slap ons.


Very modified but.....a high budget catalogue car, a bit yawn....americans are flooding the world with these kind of NFS builds, and it's really killing this style for me, especially the wide bodies...


I'm not going to 'hate' on this, but I really wonder why so many people choose to use expensive and exotic materials just for looks, instead of using it to improve performance.

If it's a car show car, than it's a car show car. But, some people seem to think that they can have their cake, and eat it too. But, it's just a total waste. The fact remains, you're doing it wrong.

And, that's fine, if that is your intention. But, personally, I am a little saddened by the waste. It's one thing, to build and design a vehicle to exceed all performance limits, but I just don't understand the car show culture, I guess. I mean, this is Speedhunters, not Showcarhunters, right?


Hey Jim,
If you read the article there are several links to some of my previous builds for a prior company as well as my personal time attack built RX7. One of my previous builds that was at the same level actually was shipped to Japan to display at Tokyo Auto Salon ahead of being tracked at Tsukuba Circuit. The first time this build was even thought about was while talking to a teammate on track at Fuji Circuit for Formula Drift Japan.

All of my builds and especially personal cars are built to perform. As in a complete car... checking every single box of usability. This car was built in 4 weeks for this particular event and we managed to do some pretty ground breaking engine accomplishments that most of the world hasn't attempted in the last 5 years. This project is definitely a street oriented build in contrast to my FD.

Going from 190whp to 408whp on a Renesis II... is pretty insane and pretty fun to enjoy on the street.

Having my 550whp RX7 for the track... why do a full carbon interior and re-upholestered Recaro's in Alcantara?... I think its cool and I can. After 10 years in the industry working with Time Attack to Formula Drift Teams, Project Managing some of the largest builds in the world, and then taking time to polish my own style... I realized the best part about building your own cars is that there is no "right" or "wrong"... its your own doorway or terminal of expression. (Even if I'm honestly in the Function>Form camp).

I think having the ability and follow through to do something different is everything in contrast to people who don't have the opportunity to build at all. Since this is a new project.. the future is unwritten for what my team and I plan to do with her.


Don't take the name too literally. We're pretty evenly spread across all facets of car culture.