SURVIVING THE PLUNGE
EIGHT YEARS AFTER HE CHOPPED UP HIS SHOW CAR, WE CHECK IN ON SHAUN JUDD’S EPIC HOME-BUILT GT1-SPEC FC RX-7
UNDER THE SKIN OF A GT1 RX-7
One class within the upper echelons of New Zealand motorsport exemplifies the Kiwi can-do attitude by offering such a loose set of rules that mad scientists– cum–race engineers can piece together tin-top machines capable of blisteringly fast lap times. It’s a class in which only one’s imagination, practical ability, and lust for speed are the hurdles between you and how fast you can go.
GTRNZ is home to our country’s fastest tin-top circuit racers, and one of them is the wildest-looking RX-7 you’re ever likely to lay eyes on. But the best bit about the flame-spitting FC is that owner/builder/pilot Shaun Judd has managed to piece together this weapon right from inside his humble two-car home garage.
It’s not the first time that we’ve pointed a camera at this FC, and, if we’re honest, we doubt it’ll be the last, as the 17-yearlong project has seen Shaun’s once-show-car-quality street car undergo more operations than Mickey Rourke. But in all that cutting, reworking, and reshaping in the quest for speed, surprisingly, the FC still hasn’t lost its soul — it is still instantly recognizable as an FC, and a surprising amount of factory tin remains, including most of the chassis rails, floor, firewall, and roof, all of which are a nod back to the original intention to run under the SS2000 regs. That plan quickly derailed and diverted onto a new track into what was then known as ‘Super GT’ and now as ‘GTRNZ’, a move made due to the restrictions placed on rotaries in SS.
It was 2010 when we first took a look at Shaun’s handiwork on the FC. It was then powered by a naturally aspirated 13B peripheral port (PP) and had the same basic suspension layout that you see today, although it was all a lot less developed than it is now. The custom double-A-arm configuration front and rear, pushrod Koni coilovers, and custom uprights were all fabricated by Shaun, and, for all intents and purposes, it was an oversized 224kW go-kart, which is fitting when you recall that Shaun had built the car as his step up from competitive karting.
After a somewhat lacklustre first season, the upgrades began, a close-ratio box, adjustable sway bars, new rubber, and an extra 60hp extracted from the 13b by Brent Curran, soon brought the FC up to speed — a little too much speed, as it turned out, as Shaun broke out at both Taupo and Pukekohe: “We ran a 1min 04.4s at Puke; I never thought we’d break out there.” This forced a shift to GT2, although they were now at the back of the grid again. “We needed some extra power. It was either build some sliding throttle bodies and try [to] get some more pace from the PP, or add in some boost,” Shaun explains. A super simple set-up soon turned into a package that produced 328kW the first season and 410kW the following one, after switching from avgas to E85. The car was no longer hampered by a lack of straight-line speed or relying solely on cornering pace to keep up; it now had the boost to battle those bigger capacity V8s on the straights, which placed Shaun squarely at the pointy end of the GT2 class. But, as with any homebrew racer, there are always improvements to be had, and the team never stopped upgrading, or re-engineering, parts as budget or imagination allowed.
The biggest ‘upgrade’ was forced by the cold, hard slap of a concrete barrier during the 2013 ITM 400, when the FCs clutch failed bringing it to a hault on track. Hit from behind, the resulting crash damage was extensive, completely destroying the rear end
Both the front and rear blade-type sway bars are adjustable right from the driver’s seat. Working between a horizontal and vertical position, the more horizontal the blade is, the softer the bar
and bending the front. It wasn’t a pretty sight, although it did give Shaun the excuse to re-engineer the suspension design, this time ditching the rear chassis rails and modelling everything using CAD.
New bodywork was needed, so the opportunity was seized to step to broader 280mm wide 18-inch slicks (and wheels). Kilos were also saved, bringing the kerb weight back down to what it once was with the naturally aspirated (NA) motor. These savings came in the form of new fibreglass doors, bonnet, rear hatch, and Lexan windows all round. The rear wing doubled in size and was attached directly to the chassis. A second wing appeared on the boot, and new aero up front included a large splitter, bonnet vents, canards, and box-style side skirts. The ride height dramatically decreased, giving the car an almost body-dropped look, with flares that now towered over the bonnet line.
It was almost two years after the crash that the FC resurfaced, displaying Shaun’s trademark meticulous show car presentation. The attention to detail was second to none, paired with his fabrication abilities — showcased via myriad laser-cut plate and bent tubes. But the two-year rebuild nearly went up in smoke during
the first time out at REunion, when the trademark flame-licking exhaust got away and took hold in the rear corner: without fire marshals on track — it wasn’t a race event— the mercury was soaring and flames spreading fast by the time Shaun made it back into the pits.
Despite this set-back, it wasn’t long before Shaun was back in the GTRNZ fold, and those upgrades made an instant impact, as, this time, he was nipping at the heels of GT1 class times. So, when a shake-up of the class breakout times was announced ahead of this season, Shaun knew exactly what upgrades would get him up to speed for his promotion to GT1. The old (and heavy) GForce was swapped for an HGT Precision six-speed sequential. Aside from chopping nearly a second from his lap times, it also helped Shaun be as precise as possible in the driver’s seat. This home-built warrior now found himself on the grid among a pack of wolves, and these wolves were showing their teeth. These were professional-built race cars, many with all the best pieces in all the right places, and the little 13B now had its work cut out to keep up, so Shaun’s driving had to be on point at each and every corner. Any mistakes would cost the torque-less 13B big time, “The biggest thing is you can be mid corner now and you can just pull another gear without thinking about it. Now if it comes on boost
The current weight sits a few kilos over a tonne. This means that when the ‘passing’ switch is hit and all 462kW is released, the car is a real rocket ship. Shaun admits, though, that the V8s he races against have a far easier job, as one mistake in gear selection exiting a corner is hard to come back from, unlike in the V8s No, your local dump truck isn’t missing its turbo. This is actually a Holset HX55 built by Turbochargers New Zealand, and sitting on a custom stainless manifold
and starts to step, I can bog it by short shifting,” he says.
However, best-laid plans have not seen a fruitful debut GT1 season, due to the new motorsport power-steering pump. This problem plagued the car and was eventually traced to the pump being supplied with the incorrect pressure-relief valve. It’s fair to say that it’s been a season the team would much rather forget. But this is motorsport, and they are not about to give up. In fact, the day before our shoot, new AP Racing Pro 5000 brake calipers found their way onto the handcrafted uprights via a pair of CNC’d mounts — whipped up, you guessed it, by Shaun. But that should come as no surprise, as you’ll struggle to find a custom piece on the car that he hasn’t built. It’s a never-ending challenge in the quest for speed, and one that shows no signs of slowing. In fact, this photoshoot is just like our last, when Shaun was speaking about the turbo motor it has now: there is more talk of a similar nature, only, this time, it involves making his own crank. We’ll let you join the rest of the dots on that one.