Ball Tearer Brumby

This article was first published in 2006.

Ask the farmer who used to own this Subaru Brumby to guess where it is now and he’d likely say rusting away in a dam or compressed into a neat 1 metre cube. But how far from the truth can you get?! Nathan Townsend’s Brumby ute is arguably the best in the world and, thanks to a serious EJ-series engine conversion, it’s one of the fastest. Not many Subaru utes are knocking on the door of a 9 second pass...

The idea to create a Brumby street/drag car (with an increasing emphasis on drag) came to Nathan after owning a ’99 Impreza WRX with a front-mount intercooler and few other bolt-ons. It was a quick car but Nathan saw the immense performance potential of the lightweight Brumby and the opportunity to do something a little different.

After purchasing a farmer’s 1989 Brumby, Nathan immediately got stuck into transforming the mechanicals while the body underwent a revamp. Nathan’s a pretty handy kinda guy and performed about 98 percent of the engine/driveline conversion himself. But given Nathan’s desire to run 9s, there was no point dropping in a stock EJ20 turbo engine so the engine was first rebuilt to ‘Super Subie’ specs by local tuning shop PerFOURmance Motorsports.

The engine comprises a 2.2-litre EJ-series block with a 2.4-litre aftermarket stroker kit, forged pistons and rods and modified DOHC heads. Oversize valves and custom cams give extra breathing capacity. The engine is built with an aftermarket stud kit and all the good bits you’d expect in a drag motor. A PWR aluminium radiator and Davies Craig 10 inch thermo fan keep it running cool.

An off-the-shelf exhaust manifold and custom up-pipe connect a Garrett GT35/40 turbo combined with a 42mm external gate. With boost set to a max of around 25 psi, the heated charge air is chilled by a PWR barrel-style water-to-air intercooler. Interestingly, the water lines for the water-to-air ‘cooler pass through an esky which is mounted behind the cabin - Nathan throws in a couple of bags of ice to help reduce peak intake air temps from around 45 to 10 degrees Celsius. Stainless plumbing routes through the engine bay and a single TurboSmart blow-off valve is installed.

The intake to the turbo comprises a large pod filter on the end of a mandrel bent length of tube while exhaust gasses exit via a 3 ½ inch system with twin 3 ½ inch straight-through mufflers. Interestingly, the engine runs a custom intake manifold that – while it appears similar to the stocker – provides perfectly even length runners and a custom plenum volume. A big-bore billet throttle ensures there’s plenty of airflow into the intake manifold.

Controlling the fuel and ignition systems is a MoTeC M400 programmable ECU with data logging and various other options ‘unlocked’. Rochester 1000cc injectors suckle from custom rails teamed with an AEM pressure regulator and you’ll find large diameter braided lines extending back to the Magnafuel pump teamed with twin Bosch 044s pumps. A custom alloy fuel tank (with extensive internal baffling) is mounted under the tray. The CDI ignition system is controlled by the MoTeC and Mercury Marine ignitors are employed. Tuning (and much of the drag setup) has been performed by the experienced team at Advanced Performance Centre is Brisbane.

From the outset, Nathan decided to go with a tricked auto driveline rather than a dog box manual. In a drag application, the auto trans is gentler on driveshafts and, with the right torque converter, it’s relatively easy to get off the line. The ex-Subaru Legacy twin-turbo auto trans has been tricked with numerous internal mods, a B&M shift kit, oil cooler and a 5500 rpm torque converter. This might seem a bit excessive but not when you consider the engine’s rev limiter is set between 8700 and 9200 rpm... With plenty of stall applied, Nathan’s Brumby can leap off the line with 18 psi of boost – not bad! The rear diff is a R180 unit from a Liberty/Legacy RS and relatively short 4.11:1 gears are used. A custom heavy-duty tailshaft is installed and axles are rebuilt Brumby items that Nathan says are suitably beefy.

Interestingly, the front-end runs Impreza WRX struts which went straight into the Brumby aside from the need to redrill the upper mount holes. The WRX struts have also been modified to provide adjustable ride height and incorporate adjustable damping. The rear suspension retains the standard Brumby torsion bar arrangement with the switch to adjustable dampers. Some further suspension development is a possibility and Nathan says a lot has already been gained by playing around with tyre pressures. Stiffening the rear dampers also eliminated the problem of the front left wheel lifting off the ground during launch. Brakes are Liberty RS/early WRX spec with a custom brake box comprising dual master cylinders. There’s no vacuum assistance but Nathan can always rely on the rear-mounted parachute.

While the majority of the engine/driveline was being assembled, the farm-battered Subaru body was brought back to life with some detailed panel work and a new colour. A retired friend, Bob, massaged the panels, smoothed the side panels and rolled a new rear number plate surround panel and tailgate (not fitted at the time of our photo shoot). With the metal straightened, a coat of Mazda6 blue was applied (a similar shade to Pro-Drive blue) as the final touch. Seventeen inch Type R alloys are fitted for street use while Subaru 15s and Hoosier slicks are used at the track.

Inside, the cabin has been comprehensively prep’d for drag racing. You’ll find a pair of Velo race seats, RPM harnesses, a fire extinguisher and an eight-point roll cage with removable side intrusion bars for street duties. The trimmed dash panel is home to a wall of AutoMeter gauges – engine rpm, speed, fuel and oil pressure, boost, water temperature and fuel level. There’s a multi-purpose warning light connected to the MoTeC unit and a large shift light set to prevent Nathan bouncing off the 8700/9200 rpm limiter. There’s also a programmable Shiftmaster unit that allows Nathan to unlock the front and rear sections of the driveline (the Subaru auto is fully electronically controlled). By disengaging the rear section of the driveline, Nathan can do a front-wheel-drive burnout to warm the front tyres before staging. The Shiftmaster also enables push-button shifting with gear position shown on a nearby LCD display. There’s an infrared connection between the Shiftmaster and its LCD display.

At the time of photography, the car was putting out comfortably more grunt than any other Brumby we’ve heard of – 417hp (311kW) at all four wheels on a Dyno Dynamics chassis dyno! This was more than enough to propel the little ute (which weighs 2410lb with driver) down the quarter mile in 10.5 seconds at 129 mph. Damn quick but, unfortunately, not quick enough to meet Nathan’s expectations. As a result, a larger 35R turbocharger has been bolted on and, with 3 psi extra boost and C16 race fuel, power has shot up almost 100hp. You’re now talkin’ a 498hp (372kW) at the wheels Brumby...

With its extra grunt, Nathan’s Subaru has recorded a 10.2 second pass but with a badly slipping transmission. Some further trans development is happening as you read and, yes, it appears 9s will be realised. Once that’s done, a nitrous kit might enter the equation...

It’s enough to blow the hat off an ol’ farmer!

Contacts: Advanced Performance Centre +61 7 3341 7223 www.apc-racing.com PerFOURmance Motorsports +61 7 3808 4244 www.pms.net.au

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