NZ’S MOST POWERFUL K- SERIES HONDA
R32 GT-RS WERE THE KINGS OF THE DRAG-RACING SCENE INTERNATIONALLY THROUGHOUT THE ’90S. HAYDEN THORN’S EXAMPLE PROVES THEY’RE STILL A COMPETITIVE PACKAGE
Hayden Thorn is no stranger to building a high-performance Nissan. With several builds up his sleeve, all with RB26s, working experience at Nelson’s main tuning company, and an addiction for serious amounts of boost through monster singles, there is no doubt Hayden could build something capable of decimating everything with minimal effort come race day. The RB26-powered R34 Hayden had at the time would be more than enough for most of the population — but not Hayden. So began the hunt for something built to destroy.
When Hayden set out to find something worthy of building, he didn’t ever expect to discover a vehicle with as much pedigree as the one he found. A good friend of Hayden’s had recently purchased a white Nissan Skyline GT-R from a guy in Wellington, who had in turn originally purchased it from Bling Bling Motor Co in Christchurch complete with an OS Giken RB30. Unfortunately, the GT-R came stripped when Hayden’s friend purchased it — stripped, that is, of any evidence that it used to be owned and abused by New Zealand GT-R drag-racing legend Reece McGregor. Hayden somehow managed to convince his friend that the GT-R should change owners immediately, and he ended up as the new owner of this certified dragster. “Once I found out the bare chassis had already been certified for an RB30 engine, had adjustable coilovers, a half-cage, Mines dash, and had racing history, I knew it was worth every penny,” Hayden told us.
With the GT-R now in the shed, it was time to start the new project. “I decided to pull the engine out of my R34, which was an RB26DETT with a Holset HX35, and install it into the GT-R to get
it running. I modified the oil system, installed a four-wheel drive sump, and fitted a new racing clutch. It was now time to go racing.” Hayden explained. There was no denying the pedigree — Hayden managed consistent low elevens straight out of the shed, which was very promising. Unfortunately for Hayden’s gearboxes, they just couldn’t handle the constant abuse that was getting dished out to them down at Motueka’s very own dragway as Hayden explains, “Three months of constant drag racing, and I managed to chew through three gearboxes. It was starting to get extremely expensive at this stage, so an upgrade was definitely needed.” Hayden decided he’d bite the bullet and import a GReddy Quaife six-speed H-pattern gearbox from Japan, which in itself was the price of five more GT-R gearboxes. With the power now reliably getting to the ground, it was only fair that the engine decided to have its turn to break. The RB26, with a bent crank was now also in need of an upgrade.
Given that the GT-R was already certified for an RB30, it was no surprise that Hayden purchased an engine out of an old Holden Commodore VL with a blown head gasket to convert to a Frankenstein engine. A new RB26 head was purchased, which had extensive porting (completed in-house by Top Secret in Japan and Trust 272 degree cams), perfect for the amount of impending boost. Instead of running the Holset HX52PRO which was originally planned, Hayden decided to keep everything Japanese and had a friend import an HKS T51R SPL turbo. “I’ve always liked the look of the HKS T51R SPL turbo, they sound amazing and they flow enough air for the power I was after,” Hayden explains. The RB30 block was completely rebuilt and strengthened with STA Parts pistons, ARP rod bolts, ARP head studs, and a Cometic head gasket. Hayden decided to leave the rods as factory. Once the HKS T51R SPL was bolted to the HKS SPL manifold, the fueling system sorted, and the Spitfire-series two-coil packs installed, it was now time for a tune down at NDT Developments. “We decided to run the RB30 on a strict diet of E50 ethanol fuel which netted some very impressive gains. On 27psi of boost, the RB30 made 521kW (700hp) at the wheels, with plenty of room for more, however we decided to leave it at that to guarantee us reliability. I was now itching to get it back to the drag strip,” Hayden told us.
A couple of drag days later and Hayden was smashing tens out like they were nothing. The package was proving to be extremely potent as expected, but it wasn’t until a local V8 drag day, which Hayden attended, that things started to get really exciting, he explains. “I decided to take the GT-R to take on some V8s at a local low-key drag day and after a string of very low 10-second passes, I managed to lay down a 9.97-second pass at 140mph. That was the end of my days racing, as the bolt-in roll cage isn’t permitted to run that fast.” With another 5psi of boost and some more timing which the RB30 can easily handle, Hayden predicts the GT-R will be running in the low nines. “I want to get the GT-R into the low nines, or even high eights would be nice. This won’t be happening until I have a full weld-in roll cage, more grip, and more boost. So, I’m excited to get it back out when the next phase of the build is complete,” he enthuses.
We’re sure that with the heritage this GT-R has, the dedication Hayden has to progress, and the addictive nature of going quicker — which got Reece McGregor into the sevens — we’ll see some exciting stuff from Hayden and his GT-R in the near future.
9 SECOND GTR
DRIVELINE GEARBOX: GREX/Quaife six-speed
straight-cut dog box CLUTCH: Tilton triple-plate FLYWHEEL: Custom
POWER: 521kW (700hp) at the wheels on 27psi of boost and E50 fuel
0-400M: 9.97@ 225kph (140mph)
EXTERIOR 0PAINT: Factory ENHANCEMENTS: N1 front bumper and side skirts, N1 headlights, Bomex mirrors
MODEL: Nissan RB30E, 3000cc,
six cylinder BLOCK: STA forged pistons, ARP rod bolts, ARP head studs, Cometic head gasket, GReddy oil pump, modified crank, Tomei sump baffle, external head drain, RB30 four-wheel drive
sump adaptor HEAD: RB26DETT, ported, bronze valve guides, modified combustion chamber, Trust 272 cams, HKS cam
gears INTAKE: GReddy intake manifold, Q45 throttle body, 4-inch intake pipe,
Unifilter air filter TURBO: HKS T51R SPL WASTEGATE: HKS 60mm FUEL: 2x Bosch 044 fuel pumps, custom surge tank, Sard fuel pressure
regulator, braided fuel lines, GT-R lift pump, HKS fuel rail, Injector Dynamics
ID1000cc injectors IGNITION: Spitfire series two coils EXHAUST: HKS SPL manifold, custom V-band 4-inch straight-through system COOLING: Alloy radiator, HKS GT front
mounted intercooler ECU: Haltech Platinum Pro OTHER: 420 Industries catch tank, Cusco brake master cylinder brace, braided wastegate lines, carbon air
diffuser, painted rocker covers
Believe it or not, the Mines gauge cluster was one of the reasons Hayden originally made the decision to purchase this GT-R back when it was a bare shell
SEATS: Bride Zeta III driver seat, R33 GT-R passenger seat STEERING WHEEL: Personal INSTRUMENTATION: Mines 320kph speedo, GReddy boost
and water temp gauges OTHER: HKS 4WD controller and drag adaptor, Cusco boltin roll cage, Sony head unit,
STRUTS: HKS Drag R adjustable coilovers
SPRINGS: HKS OTHER: Midori front camber arms, Tein castor arms, Cusco rear camber arms, Hicas delete kit, Cusco rear strut brace BRAKES: R33 GT-R Brembo calipers and rotors
How much fuel is needed in a car of this calibre? A lot. Try two Bosch 044 fuel pumps, a custom surge tank, a Sard fuel pressure regulator, braided fuel lines, an HKS fuel rail, and six Injector Dynamics ID1000cc injectors
SUPPORT WHEELS: 18x10.5-inch Varrstoen ES2 TYRES: 265/35R18 Toyo Proxes R1R
With the need for serious traction, Hayden has opted for some serious wizardry seen in Japanese drag GT-Rs of the ’90s. Items such as the HKS electronic torque split controller and the HKS drag adaptor play a huge role in getting the power to the ground
There aren’t many turbos around that sound as spectacular as the HKS T51R and they have been the turbo of choice for over ten years for people wanting to produce over 500kW. Hayden’s T51R SPL sits on top of a HKS SPL turbo manifold and is controlled via the 60mm HKS external wastegate.To keep things in the family, an HKS GT intercooler has been utilized to cool the turbocharged air
DRIVER PROFILE DRIVER/OWNER: Hayden Thorn
AGE: 25 LOCATION: Motueka OCCUPATION: Mechanic BUILD TIME: Six months LENGTH OF OWNERSHIP: Two years THANKS: Brian at NDT Developments and all of my friends who have been involved with the build