Tsukuba Circuit is hallowed ground in the time attack world, but for most enthusiasts outside Japan, the dream of hitting this iconic track in real life remains just that – a dream.
For Jacky Tse of JTune, a New Zealand-based tuner and die-hard time attack fan, however, that dream wasn’t something to just watch from behind a screen. It was something to be realised.
Jacky considers himself a “normal driver.” While he’s a casual track instructor, Jacky is not a professional racer. His goal was simple but ambitious: to prove that anyone could show up to Tsukuba for the first time in a street car and leave with a lap time that might seem unachievable for a novice enthusiast.
Of course, there was one crucial piece to this puzzle – the car itself.
Shipping a car from Japan to New Zealand is affordable, given the massive number of used JDM vehicles exported each week. But sending a car in the opposite direction? That’s a different story. I’ve covered a similar story where four Australians shipped their drift cars to Japan for a month of track days, and I’ve kept tabs on their ongoing adventure. From Australia or New Zealand to Japan, car shipping costs are only the tip of a very expensive iceberg – and that’s before you factor in the return trip.
For Jacky, sending a car from New Zealand didn’t make financial sense. A much better idea came during Tokyo Auto Salon 2024.
A year ago at Makuhari Messe, HKS unveiled a wide-body GR86 to showcase a fresh initiative for the company: The HKS. Drawing from over 50 years of tuning experience, this division has been set up to create fully built street cars for customers – from mild to wild. Knowing HKS already had a successful time attack GR86 in its R&D fleet, Jacky asked if he could purchase the car on display, with the intention of taking it to Tsukuba. The answer wasn’t completely straightforward.
Initially, Jacky was told he could buy the prototype ‘The HKS’ GR86, but as it transpired, the car had already been sold – to another Jacky, which may explain some of the confusion. It wasn’t all lost though. If he was willing to wait, HKS could build another car – ‘The HKS’ GR86 customer chassis #1 – and then run it with him at a Tsukuba time attack event.
This option turned out to be even better. Jacky could spec the car exactly how he wanted within the boundaries of what HKS defined as a ‘street car,’ and have time to properly prepare for the driving challenge. A few months later, a contract was signed, the deposit paid, and in June, ‘The HKS’ division began work on a new Toyota GR86 RZ in Crystal White Pearl.
By August, the core of the build was finished. By December, it was fully completed – just in time for the second and final 2024 HKS Tsukuba Hiper Challenge. This is when I joined Jacky and over 40 of his friends and family for the occasion.
Before diving into how the day unfolded, let’s take a look at the car…
At a glance, it’s clear this is no ordinary GR86. Street legal? Yes. Subtle? Not even close. The car sports a full HKS Type-R body kit, widening the front by 55mm and the rear by 65mm (per side). This is further enhanced by HKS SPL CRFP (carbon fibre reinforced plastic) canards, vortex generators, and an under-panel, along with a custom HKS SPL CRFP swan-neck GT wing –all of which were CFD-tested to improve high-speed stability.
The GR86 runs two sets of 18×11-inch +30 Yokohama wheels – Advan GT Beyonds and Advan Racing TC4s, which were wrapped in Yokohama Advan A050 295/30R18 semi-slicks for Tsukuba. HKS Hipermax R coilovers enhance the car’s handling while Endless 6-pot front and 4-pot rear brakes ensure it can stop.
Inside, the full HKS catalogue has been unleashed.
There are HKS 50th (anniversary) Bride Zeta IV front seats, HKS 50th TRS 6-point harness belts, and an HKS 50th Nardi Sports 34S steering wheel. Not forgetting its street car credentials, HKS floor mats and a luggage mat in the trunk complete the look. For its day at the track, the passenger Bride seat and mats were removed, but everything else remained.
Finally, the powerhouse and HKS’s bread and butter of the build – the engine. From its original 2.4L naturally aspirated specification, HKS stroked the GR86’s flat-four to 2.5L using their Short Block Step 2 kit, which includes forged pistons, I-beam connecting rods, and a forged crankshaft with a crank key.
To bring the power, an HKS GTIII-RS turbo kit was added, complete with the turbocharger, exhaust manifold, 113mm catted downpipe, intercooler, and a Super Power Flow air filter. Supporting the upgrades are a variety of HKS parts, including a grommet-type head gasket, Fine Tune V-belt, Hi-Power SPEC-L II exhaust system, and an S-Type oil cooler kit. Dress-up parts, like the HKS dry carbon fibre engine cover (removed in these photos) and fuse box cover, and the HKS oil filler cap, complete the engine bay.
The GR86’s factory ECU remains, but it now has an HKS F-CON sub-ECU, HKS EVC 7 boost controller, HKS ATK A/F Knock Amp, and an HKS VAC II (speed limiter removal) running alongside it. The power output? With 0.7bar (10.3psi) of boost dialled up, a conservative 350hp.
This was the full HKS catalogue build, with no cut corners. However, Jacky had an extra request above and beyond the scope of the driveline upgrade, which initially just added an HKS LA (Light Action) clutch: Fitting a race-spec limited-slip differential, and a Quaife 69G 6-speed sequential transmission from Momentum Motorsport in the United Kingdom, one of Jacky’s long-standing partners.
At first, HKS wasn’t fully on board with this deviation. But when Jacky showed up at the Fuji HQ mid-build with a Cusco RS 1.5-way LSD in his carry-on luggage and the news that the Quaife gearbox was en route, the team came around. After all, even HKS had encountered issues with stock GR86 transmissions failing under boost on track, and a broken box was the last thing Jacky wanted to have prematurely cut short his day at Tsukuba.
Originally, Jacky was supposed to get some test laps before the Hiper Challenge, but as often happens with these projects, the build went down to the wire. His first time behind the wheel would be at the event itself. And with only three short 15-minute sessions to work with, laying down a respectable lap time – Jacky’s goal being sub-1-minute – was going to be anything but easy.
The day started with high spirits, but things took a quick turn. Jacky hadn’t even made it out of the pit lane when the engine stalled and couldn’t be restarted. After the car was pushed back to the HKS pit, the issue was traced to a loose crank angle sensor. Session one: done.
To properly solve the sensor issue, the transmission would need to come out of the car to give full access to it. There was no time for that, so a side-of-the-road fix was employed, allowing Jacky to head out for session two.
Jacky had been preparing for this day for six months, running hundreds, if not thousands of laps on his simulator. But Tsukuba’s real-world elevation changes, corner camber, and track narrowness were all things he had to quickly adapt to. During the second session, he was understandably cautious, knowing that crank angle sensor failure at speed could end in disaster. Furthermore, the car was understeering, and the brakes weren’t performing as they should, mostly because the pads hadn’t been bedded in and the suspension settings needed tweaking. The big aero was hampering its straight-line speed too. Still, Jacky lapped at 1:03, a solid start.
After some tweaks and with confidence that the crank angle sensor issue wouldn’t resurface, Jacky geared up for the third and final session. He had a strategy: warm up on lap one, then push for a time on lap two, and lap three if necessary.
There was immediate improvement with a 1:01 first lap. But on lap two, the engine began to overheat, initially causing power loss and then a misfire. Jacky returned to the pits for a cool down, but on his return to the track the misfire persisted. Not wanting to risk the engine, the session was called.
Although the teething issues didn’t allow Jacky to hit his lap time goal, the GR86’s performance was impressive for a first shakedown.
Hit play above to ride along with Jacky for a few laps around Tsukuba.
At the end of the day, Jacky noted, “This project wasn’t just about a build or a lap time. It was about fulfilling a lifelong dream with my friends and family, and celebrating car culture at Tsukuba, the world’s most iconic time attack track.”
While this was supposed to be a one-hit Tsukuba deal, with HKS returning the GR86 to its HQ after the event and immediately prepping it for export to New Zealand, there’s a chance Jacky will get a second shot at that 59-second lap before Japan’s 2024/2025 time attack season is over. HKS has fixed the crank angle sensor issue and is currently fine-tuning the setup, so we’ll see.
In the meantime, you should definitely check out Jacky’s YouTube channel, Seat Time, where his ‘Road to Tsukuba’ has been documented in detail.
Alec Pender
Instagram: noplansco
