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Custom Duramax-powered Nissan GU Patrol review

By Dan Everett | Photos: Nathan Jacobs, 09 Mar 2018 Custom 4x4s

Custom Duramax Nissan GU Patrol

With 2000 Earth-rumbling newton metres, this isn’t a snowball – it’s a full-blown avalanche.

THESE hallowed pages are no stranger to the occasional snowball. Hell, we’ve been personally responsible for more than a few over the years ourselves.

They start out as a reasonably sedate project, something designed for camping trips, light wheeling and maybe yanking the occasional trailer around… until it all gets out of hand. If most of our builds are snowballs, Ant’s killer Patrol is an avalanche.

What started out as a mild-mannered farm truck is now packing a 450 per cent torque increase, sports car-trumping speeds and off-road ability that’d rival anything this side of a mountain goat.

If Ant’s bearded mug looks familiar there’s a good reason. One of his 4x4s graced the January 2018 cover: a Duramax-powered PX Ranger – yeah, you read that right.

This time he’s brought out the big guns, his ’01 GU coil-cab pounding out a mind-melting 2000Nm and 836rwhp thanks to yet another 6.6L V8 Duramax swap; although, this one’s tuned to within an inch of its life.

In stock form the bent-eight will put to shame anything offered within the Australian market. However, what does it take to make it punch out more than double the power and torque?

First things first, you rip it down to a bare block. The stock pistons and con rods were binned. In their place are forged rods from Carillo, which are topped off with ceramic-coated pistons from Mahle Motorsports designed to handle 1000hp.

From here an ATI balancer was fitted at one end, with a Wagler billet flexplate at the other. An aggressive camshaft was slotted between the two banks of pistons; although, with an altered firing order it’s designed to improve longevity, not just punch out more power. The stock heads were also shelved, and atop the Duramax are a set of CNC-ported offerings from Socal Diesel stuffed full of oversized valves.

Finally, a 12mm injection pump was strapped to the oiler, with 150 per cent oversized injectors satisfying the powerhouse’s insatiable thirst for diesel.

The turbo was upgraded to a billet 72mm VGT offering, breathing deep through the five-inch snorkel and airbox fabbed-up in-house at Ozmax Conversions, with an Ozmax front-mount intercooler between the turbo and intake.

The whole affair is reigned in with a DSP5 tuner, allowing Ant to select anything from a mild tune right through to the balls-to-the-wall power tune – “I lined up against a 600rwhp FPV F6 Typhoon and blew the doors off it,” he laughs.

With three times the torque of a 79 Cruiser flowing through the Patrol’s veins, a standard transmission would last about 30 seconds before turning itself inside out. Backing up the Duramax is none other than the venerable six-speed Allison transmission.

In typical Ant fashion it’s had somewhat of a tickle, and by somewhat of a tickle we mean it’s a fully built item from Limitless Diesel. It’s sporting everything from billet shafts throughout to a race-ready shift kit, clutch packs and billet baskets.

From here, power feeds through to an Ozmax Conversions transfer case adaptor into the stock Patrol transfer case. With the transfer case sitting 50mm rearwards to suit the engine, both front and rear driveshafts needed to be custom-built from heavy-wall chromoly, to suit the new lengths.

Up front the factory diff runs an Eaton ELocker wrapped around 4.11 cryogenically treated diff gears. Longfield 300M chromoly axles and CV joints have been slotted inside to send power to the front wheels.

Product test: Harrop-Eaton ELocker

In the rear a locker simply wasn’t an option. “When you’re pushing this much power a locker in the unlocked position only sends power to one wheel, it just can’t handle the torque,” Ant told us. Instead, he’s installed the stronger H260 rear diff and then yanked it apart and shimmed the LSD.

He’s also cryo-treated the axles and gears, too: “While I was getting the diff stuff cryo’d I did the gears and chain from the stock transfer case, too. It doesn’t need it, but why the hell not?”

To make the goliath engine fit in the comparatively small Patrol, Ant knocked together custom mounts from front to back, then extensively massaged the firewall to clear the dump pipe without running a body lift. Despite all that, Ant tells us that’s only half the battle.

“Getting the engine in is the easy part,” he said. “The wiring, intercooler piping, coolers and airbox all took far more work.”

With most of the Patrol’s weight over the front axle, Ant’s gone for an unusual, albeit successful, approach to his suspension. Up front are Fox 2.5 body remote res DSC shocks, with the rear copping smaller-diameter 2.0 remote res Fox, all from Down South Motorsports.

“With the weight difference, the larger body shocks in the rear would have actually made it ride worse,” he told us. “As it is, it’s unreal. You can hit anything flat-out in it.”

Of course, it’s not all about shocks, either. Up front the diff is kept in place by a set of Ozmax long arms, at 350mm longer and with a Cruiser bush end they’re able to take full advantage of the big shocks and 3.5-inch-taller coils. The rear is running 300mm longer lowers from Down South Motorsport, with heavy-duty adjustable uppers helping correct pinion angle after the two-inch King flexxy coils went in.

PSR adjustable Panhard rods front and rear keep it all centred, with a matching tie rod and drag link up front. Ant’s swapped out the stock front guards for a set of Kevlar replacements that sit two inches wider, with an opening that’s also two inches wider. It provides ample room for the 37 x 12.5-inch Goodyear Wrangler MTRs to stuff up into at full articulation. They’re able to run at insanely low pressures, too, thanks to 17 x 9-inch -30 Allied Rattler beadlocks at each corner.

While the tube bar work front to back might look comp-ready, Ant’s built the tray with his furry friends in mind. A removable frame clips onto the tube frame work, which is then wrapped in a canvas canopy to provide shelter for the dogs and a dry spot to stuff a swag or two for camping trips.

Inside, the madness doesn’t stop. Ant’s opted for the base model DX for its rugged vinyl flooring and manual wind-up windows. He’s then proceeded to deck it out head to toe in off-road goodies.

Built not bought at 4x4 Australia Custom 4x4 reviews

The pews have been replaced with leather reclining Recaro bucket seats, with an Intervolt dual-battery system tucked in behind. Storage is taken care of by a Department of the Interior roof console with a Bluetooth-enabled XRS UHF from GME sorting out comms.

Eagle-eyed Patrol owners will notice the steering wheel as not being a typical DX tiller, either. Ant swapped it for the wheel from an imported WC34 Nissan Stagea. In the process he’s picked up steering wheel gear selectors, which, when paired with the Allison trans, let him row through the gears while holding on for dear life.

Despite being essentially a road-registered off-road racer, the big GU has pounded out the kays doing daily duties. A capable workhorse, reliable enough to head off on remote camping trips, that’ll then run with a Lamborghini Aventador? This might be the ultimate 4x4.

Just don’t ask how much it cost. 

Giggle Gas

“ONCE you’ve owned one you could never go back to a normal winch ever again.” A big claim from Ant, but when you find out what winch he’s packing it starts making a whole heap of sense.

Nestled inside the front bar is what remains of a Warn 8274, more commonly known as a high-mount. Ant’s swapped out the mediocre standard motor and strapped on a twin motor set-up from UK-based Gigglepin. The billet upper let Ant replace the stock 4.6hp motor with two 9hp units, modified versions of the 6hp Warn XP motor.

At the flick of the switch the twin 9hp units are pushed to their limits with a Red Winch “Supercharger”, kicking voltage up from 12V to 24V. Drive passes through 63 per cent quicker gears, before making its way through the DeltaTek air-free spool, where 80 metres of 13mm Dyneema rope are wrapped around the 76mm-wider drum... What? You didn’t think Ant would run an Alibaba special, did you?