As part of our coverage of Australian and State level off-road racing we previously introduced you to the different racing categories and, specifically, a Class 7 Nissan Patrol, Class 1 Southern Cross buggy and Class 4 truck. In this story, the final in the series, we'll take a look at one of the little grasshoppers - a Class 3 buggy driven by South Australia's Wally Francombe...
Class 3 is recognised as a very cost-effective entry category for 2-seater buggies up to 1330cc in engine capacity. Note that many of these buggies can be bought second-hand for around AUD$5000.
Attending the 2003 Waikerie Long Course Enduro (a round of the South Australian championship) were eight Class 3 buggies powered by everything from multiple carby'd Datsun 1200s to twin-cam Suzuki and Mazda 1300s.
The vehicle we'll examine here is a 1980-built Mallee Master frame, which the latest owner has converted to Swift GTi power. The vehicle is owned, driven and navigated by the husband and wife team of Wally and Belinda Francombe.
Purchased about five years ago - for just AUD$2000 including its associated single axle trailer! - this particular buggy came powered by a Toyota 3K engine. After its first competitive outing with Wally at the wheel, however, the 3K motor died and a Japanese import GTi engine was lined up as a replacement - the GTi engine being very light and with a great specific power output.
A complete 86kW Japanese-spec engine, ECU and loom package was purchased for around AUD$2000 and the whole lot was slid into the back of the buggy. The conversion meant the fitment of a VW Golf coolant radiator with an aftermarket electric fan along with a homemade 6-litre baffled sump to ensure a steady flow of lifeblood. A high-pressure supply of fuel is pushed to the injectors by an aluminium fuel tank (now mounted behind the front seats rather than at the rear, in order to improve weight distribution) containing a lift pump, internal swirl pot and an external VL Commodore main pump.
Everything remains standard, except the throttle body was relocated to the leading end of the intake manifold to help bring some weight forward of the rear axle line. Induction air filtration is a major concern in off-road racing and Wally has elected to run with a Donaldson air filter arrangement designed for... a tractor! The tractor filter has a pre-filter screen to catch large particles, followed by two more filters in series - in short, there's not much chance of debris entering the engine. Airflow restriction is not an issue either, given the airbox has 2 ½-inch inlet and outlet diameters.
Oh, and those extractors seen here are actually factory Jap-spec G13B - they've simply been adapted to flow into a short 2 ¼-inch exhaust with a 12-inch long hotdog muffler. Wally specialises in exhaust fabrication, so no surprises for guessing who did the pipe work.
Drive is channelled through a modified VW flywheel teamed with a 4-puck clutch and upgrade VW pressure plate. The gearbox, meanwhile, is a hybrid VW 1600/1800/2000 unit bolted onto the back of a custom adapter plate. A close-ratio gearset and some "beefing up" help the VW 'box in its newfound competition role, but Wally says the crown wheel area is pretty marginal. A stronger gearbox is something Wally is hoping for.
The axles are fabricated by Albins Off-Road using good ol' Porsche 930 CVs - these are noted for their immense strength and ability to cope with huge shaft angles.
The ability to "stop on a dime" is delivered by Harley Davidson front discs with Kawasaki GPX750 calipers and, at the rear, Ford Falcon front discs with Holden Commodore calipers.
Steering is via an off-the-shelf off-road specialty alloy rack with an amazingly direct 1 ¼ turns lock-to-lock (unassisted).
Absorbing the rough and tough of off-road competition is a suspension arrangement that's beem
heavily revised by Wally. The front-end uses 3-inch lengthened trailing arms, 2-inch 'drop studs', torsion bars, twin Bilstein shockers and a single coil-over spring. A lot of attention has also been paid to geometry and controlling bump-steer.
The rear-end uses 4-inch lengthened trailing arms, standard VW torsion bars, twin AusShocks and coil-over springs. We are told the rear is a fair bit stiffer than the front since the majority of weight is over the rear.
Total wheel travel - both front and rear - is around 15-inches, which is considerable for a relatively small Class 3 buggy.
"Jumps are never really a problem," says Wally, "for example, the main jump at Waikerie we just take a full throttle." Hold on!
With the recent work done to the front-end geometry, suspension and weight distribution the vehicle is also very well balanced. "It's extremely neutral, but if it ever starts understeering I can use the rear turning brakes, which act individually on the rear wheels. They make a huge difference."
Oh, and Wally has a fair idea how to drive, having experienced a few years in speedway competition.
The frame itself - made from mild steel rather than the more expensive chrome-moly alternative - has recently been modified to allow increased travel and there has been attention to reduce weight - unused shocker mounts, for example, have now been given the chop. Fibreglass panels are hung over the frame, contributing only slightly to the all-up weight, currently around 750 kilograms.
The Class 3 buggies are generally smaller than, say, the Class 1s but the cabin contains pretty much all the same equipment. Wally's buggy carries two Velo race seats, harnesses, an aftermarket steering wheel and a series of VDO gauges. A UHF radio and Terratrip intercom unit are also mounted under the roof panel. And check out the electric air blower, which connects into a dust skirt around the base of Wally and Belinda's helmets - this maintains a little comfort during an event.
A liquid-filled set of gauges are on Wally's future wish list - the existing ones flicker madly when passing over the rough stuff and can be a bit of a challenge to read...
As mentioned, the Class 3 buggies are a great entry into the world of off-roading. Since spending his initial AUD$2000, Wally has so far invested a further AUD$6000 in new shocks and suspension, AUD$1500 on the front-end, about AUD$2000 for the GTi engine conversion, AUD$1000 on driveshafts and a stack more on licensing, fuel, racewear, event accommodation a whole lot of other stuff.
He is, however, now one of the pace-setting vehicles in the class - "when we finish we generally win our class..." he says.
Contact/Thank you:
Waikerie Auto Electrical and Exhausts
+61 8 8541 3022
Thank you to http://offroadracing.com.au for their cooperation in compiling this off-road racing series.
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