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Old 09-17-2005, 01:53 PM   #1
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Default 4x4 rallycross superbeetle 650 bhp race ready

Vw beetle whit a quad-cam, 16-valve,turbo engine.
The best rallycross vw beetle in the world.

PPJ RACING's amazing rallycross Beetle debuted in the 1992 British Rallycross Championship. Peter Harrold's 4WD rallycross Beetle made its first public appearance with the newly-developed 16-valve 4-cam turbo engine at Brands Hatch in March.

The unique power unit, probably the most advanced Beetle engine ever built anywhere in the world, is the work of Harrold's PPJ Racing Team (Peter, brother Paul and John Worzencraft) together with chief mechanic/engineer Trevor Chinn. The car is sponsored by Autocavan.

In its previous guise the engine was a 2.1 litre with turbo and inter-cooler, using conventional air-cooled Scat cylinder heads with two valves per cylinder. It developed around 300 bhp.

Peter's best result was at Lydden in 1989 when he finished as the fastest 2WD car, in fourth place overall. Shortly after that they installed the four-wheel drive system, but they were also experiencing trouble with the cylinder-heads overheating.

It was to overcome this problem that they decided to follow Porsche racing practice and go to water-cooled heads. The best heads that were suitable came from a Subaru Legacy 16V.

The crankcase is basically the VW component, with the timing-gear end chopped-off and a belt-drive arrangement for the two pairs of overhead camshafts grafted on.

Cylinder liners come from a Jawa speedboat engine, chosen because they have a flange suitable for sealing against the Subaru heads. The liners are encased in Porsche barrels to provide the air-cooling, and the pistons are Cosworth. Bore is 91 mm and the crank is an 82 mm from Scat.

Kugelfischer mechanical fuel injection is used, together with a Garrett T4 turbo, giving up to 2.1 bar boost. The turbo and exhaust system is all in front of the engine, above the gearbox, with the exhaust outlet just in front of the offside rear wheel. The intercooler is contained in the rear spoiler.

The gearbox is from a Porsche Carrera, five-speed with limited-slip differential, and it has been modified by Autocavan to drive forward through a BMW propshaft to the front wheels, using Golf driveshafts and hubs. A normal BMW differential is used at the front.

The suspension is all designed by Trevor Chinn and home-made by the Team. It comprises coil springs struts and lower wishbones, front and rear, and is fully adjustable, with adjustable roll bars also. There's not much space at the front, due to the front wheel drive, water radiator, oil cooler, fuel tank, etc., and installing a steering rack proved to be one of their major headaches! They eventually used an Audi 80 left hand drive rack, turned upside down for right hand drive. Brakes are Automotive Products discs all around, similar to those used on a Ford RS 200.

Nine months' work went into the new engine and it was ready just in time for the second round of the British Rallycross Championship. A mysterious oil leak developed during practice, which transpired to be caused by the crankshaft oil seal moving back along the shaft, towards the flywheel. It was difficult to replace it, or diagnose why it had moved, without taking the engine out of the car, but they succeeded in pressing the seal back into place.

Peter missed the first heats, but made his runs in the second and third heats, posting times somewhere in the mid-field in Division 1, where the Beetle is competing against Metro 6R4s and Ford RS200s.

At present the engine is running with the standard Subaru camshafts, so it is not yet achieving its full potential of about 650 bhp. The Team was not expecting to win first time out; this was just a preliminary trial and they were very encouraged that there were no major problems.

PPJ RACING are undoubtedly pushing forward the frontiers of Beetle technology and, while similar power levels may be attained in drag racing, those engines only have to run for about 10 seconds. The rallycross engine has to last a great deal longer than that!

We look forward to seeing a Beetle among the winners in rallycross again and wish PPJ Racing and Autocavan all the luck they need.

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