JONNY GRUNWALD’S MAZDA RX-8
Fewer than five weeks until SEMA, Jonny Grunwald was feeling more relaxed than a hippie in a hammock.
It had been a hot minute since the JDM build specialist had left his project manager role at Bulletproof Automotive, and although the four-year stint had opened quite a few doors, it was nice not having to hustle for a moment.
You may recall Jonny’s white TCP Magic Mazda RX-7 from when it was showcased on the cover of Super Street last year (Vol. 21 No. 10), and how we spoke of his role as the guy behind some of the most bonkers project cars to have ever come out of the U.S. One part vehicular visionary, two parts JDM junkie, and all-around great guy, Jonny is the sort of support you want in your corner, which is precisely why those last few relaxing days leading up to SEMA ’17 were turned upside down with one swift flip of the hammock.
Jonny is no stranger to extremely tight deadlines and insane SEMA builds; it’s just that the Mazda RX-8 seen here wasn’t even close to being on his radar. At the time, pro driver Mad Mike Whiddett had been busy designing the Pandem aero kit for the RX-8 with Kei Miura of TRA Kyoto. While Mike was slated to debut an aggressive version of the kit on his tube-frame chassis race car at World Time Attack Challenge, a month before SEMA, Jonny took on the surprise assignment of agreeing to build a street version of the kit using an ’09 RX-8 he had just picked up. We guess it only made sense he’d build a sister car to his FD!
The road-to-sema build began when the car was dropped off at Auto Explosion, where the originally Velocity red RX-8 received a color change to Mineral White Metallic—the same sheen found on Jonny’s FD. He would spend much of his summer in Japan helping out the TCP Magic team competing in Formula DRIFT. After winning at Okuibuki in September, he finally flew back to complete his RX-8 with only two months in which to work. Jonny didn’t come home empty handed as he packed an RE Amemiya grille, hood vents, and eye lines on the plane.
Fun facts about this street fighter continue with the titanium wing stands, which despite their controversial aesthetics, are still one of Jonny’s favorite parts of the build. From there, we move on to the Pandem add-on titanium pieces featured on the front bumper and rear quarter attachments, along with the wing endplates. These raw materials alone reportedly cost more than his entire widebody kit combined and couldn’t even be manufactured until the Kyoto-born aero arrived from Japan, a mere nine days before SEMA!
With all the exterior bits taken care of, Jonny and his team got to scanning and designing everything in CAD, water jet cutting the titanium, and burning every piece by hand. He confesses the amount of time and labor that went into these details was absolutely asinine, especially since only the lengthened and redesigned wing stands ended up getting utilized. So, while some may hate them based purely on appearance, he loves these touches dearly because of all the time and effort that went into them.
Moving on to the engine bay, it becomes obvious that a disclaimer must be made: This is not a swap! The primary focal point of this build was that the man wanted to stick with the Renesis II, which meant implementing ass-tons of engineering in less than two weeks. Roping in Turblown from Minnesota proved to be part of the build’s success in this area, as the company had previous experience with performance Series 1 RX-8S.
With only a handful of people ever having successfully pulled off turbocharging a bridgeported Renesis II, this move was a huge gamble. This decision meant modifying the fuel rails, fabricating a custom wiring harness for OEM functionality, making a one-off manifold, installing a Borgwarner 9174 turbo, and much more to make it all work.
Being that there aren’t a lot of off-the-shelf items available for this platform, tuning had to be conducted in an extremely careful manner by multiple specialists. This meant bringing in Elliot White at Adaptronic USA (who was remote tuning in Minnesota at the time), Daniel Kuo from Garage Life, and Fris Cassola from Lucky 7, which meant more than 100 dyno pulls were made within 24 hours. After hitting 422 whp and 339 lb-ft of torque at 17 psi consistently and safely (a world record for the Series 2), the car was ready for SEMA and beyond.
To this day, Jonny assures us his RX-8 is still running beautifully after 1,300 additional street miles. Meanwhile, a debate among rotary nerds has been brewing online over the additional duo of ports on the Renesis II motor, as some feel
that the bridgeport will cause the entire engine to grenade at some point. Skeptics aside, he remains confident the car will hold up just fine, even though he does admit to having a spare engine on standby just in case shit goes pear-shaped.
As for how the vehicle performs on the street, where it was intended to roam in the first place, Jonny says in contrast to his RX-7, this build is equal parts relaxing to drive and incredibly comfortable. Air conditioning is something he hasn’t experienced for the better part of the past decade or so, and with the RX-7 preparing for upcoming track duties and high temps a factor, both performance Mazda monsters have their work cut out for them.