Tag Archives: scirocco

Bimotor VW Scirocco

Twin Engined VW Scirocco
The twin-engined Scirocco in action. It was a fully operational prototype and would have made a fine rally car.

With the twin-engined formula working successfully in the Jetta with standard engines, VW Motorsport were confident enough now to shoot for the limits of the drivetrain’s capability with the twin-engined Scirocco. The new 1,781cc engine slated for 1983 model-year production was not yet available, so VW Motorsport asked its contract engine builder, Eckhart Berg, to increase the bore and stroke of the existing 1.6-litre engine to achieve the larger capacity. With a bore and stroke of 81.25mm x 86.4mm, the larger engine worked out at l,791cc and the twin engines were thus equivalent to a 3.58-litre eight-cylinder unit. Internally, forged pistons and reworked combustion chambers increased the compression ratio to 10.9:1 and, with hotter camshafts, the output of each engine was 180bhp at 7,200rpm with 1481b/ft of torque at 5,800rpm. Helping to achieve this was a Zenith Pierburg racing fuel injection system with one throttle body per cylinder. These were basically rallycross-spec motors.

Two twin-engined Sciroccos were to be built, one for evaluation and testing and another to do shows and the like. The first car was also built to convince the VW Board of the potential of the car, and it just happened to have 54bhp more than the Audi Sport quattro rally homologation special, which it equaled in acceleration and bettered in top speed, through taller gearing. VW Motorsport and Audi Sport were run as two distinct and separate departments and one detects an element of rivalry between them spurring the VW engineers on, for it was the Audi branch that was getting all the limelight in international rallying at this period.

The power was fed through a pair of single-plate sintered-metal clutches to identical fivespeed gearboxes. Each end of the car had a limited-slip differential and, if a high final-drive ratio was opted for, the theoretical top speed was close to 180mph. In the event, the car ran with a short final drive and this gave it blistering acceleration. 0-60mph took a mere 4.5 seconds, enough to embarrass a Porsche 911 Turbo. 100mph followed 7 seconds after that and the quarter-mile trap closed on the car in 13 seconds.

Perhaps the most ingenious feature of the twin engined Scirocco was the way the engines were synchronised. Given the title ‘E-gas’, which means electronic hookup, the linking system was deceptively simple. A single throttle cable ran back to the rear engine where a potentiometer measured throttle position and sent a signal forward to operate a valve on the other engine. While the Scirocco retained the ability of the jetta to run on front, rear or both engines, it had the additional refinement of a slide-operated throttle potentiometer which adjusted front engine power and thus the front-rear power split. The car was hardly nose heavy with a good 52.6/47.4% front/ rear weight distribution, but even so it was a great advantage to be able to dial in different handling characteristics at will, especially when it came to countering understeer on loose surfaces. The gearboxes were mechanically linked by rods and cranks, with a small pneumatically operated plunger device connecting each of these assemblies near the gearbox to lock out one or the other shift mechanism in the event of a single engine failure.

The bodyshell modifications were different from those of the twin-motor Jetta. A suitable hole was cut in the shell to accept the rear drivetrain which had to be angled forward from the rear axle line. The other modifications followed the proven formula used on the Twin-Jet however, and Bilstein dampers were used together with adjustable suspension, and 10.5in vented disc brakes all round with four-pot racing calipers. The wheels were 7J x 15in Centra alloys shod with 205/50VR15 Pirelli P7s.

The second Bimotor Scirocco was a rather different animal. The project was now in the hands of Dr Ulrich Seifert at VWs Development Department and this metallic red car was brought to a state of finish where it could have been put into limited production. The car wore a specially moulded body kit which encompassed front and rear bumpers, and quattro-style wheelarch flares with engine intake grilles let into the leading edge of the rear ones. (Wheels were from an early Audi quattro.) The twin exhaust pipes at the rear were neatly centered in semi-circular cutouts rather than simply protruding from the bodywork. Open the rear hatch, and the standard of finish continued to impress. The engine compartment surround was braced with a metal frame that formed a rigid structure from the tail panel to the bulkhead, and this was carpeted. With the engine cover in place, the whole installation was hidden from view.

The interior of the car was equally neat. Instead of a battery of supplementary gauges hogging the centre console as in the first prototype, a custom made instrument panel had been assembled specially for the car by VDO who make all the instruments for VW. Fitting into the standard instrument pack hole, this contained a matching pair of rev counters with an LCD-readout speedometer in between. The bottom of each rev counter contained a small water temperature and oil temperature gauge, mirror imaged, and in the centre was the petrol gauge.

The under bonnet view was impressive. Now that the factory l,781cc engine was in production, this early 1983 prototype was able to use the new block and coupled this to Oettinger 16-valve heads. This 1800E/16 engine gave 141bhp at 6,100rpm and 1251b/ft of torque at 5,500rpm. The fuel system was a modified Bosch K-Jetronic and the compression ratio was 10.2:1.

The surprise factor in this research vehicle was that the complex gear linkages connecting two five-speed manual gearboxes had been dispensed with in one fell swoop by using a pair of threespeed automatic gearboxes. The torque convenors were modified to optimize their response and the gearbox change up points were adjusted to suit the characteristics of the sporting Oettinger engines, and the whole set-up worked very well because the slight slip in the torque convenors would help to compensate when the two engines were running out of synchronization, as when the power balance between the front and rear engines was being modified.

©Ian Kuah. This article was published with explicit permission from author Ian Kuah

VW Corrado

While in essence the Corrado has the fioorpan and chassis from the Golf GTI Mk2, its rear axle design benefits from further technical progress made between the launch of Golf 2 in 1983 and the new Passat in 1987. The most significant feature is the passive rear-steer effect given by the special bushes that locate the trailing arms. The dynamic effect of rear wheel steering is better turn-in, better crossvvind stability and more stable cornering. The Golf 2 is already very good when driven on the limit. It is initially hard to believe that the Corrado is significantly better, but those flexible bushings work very well and help to reduce understeer in fast corners. The reduced slip angles enhance cornering power and the Corrado’s poise through corners sets new standards for front-wheel-drive hatchback cars.

The Corrado 16V is about 400lb heavier than the equivalent Golf GTI 16V. Thus you have to use the gears more to get up to speed, but superior aerodynamics mean that the car is quick once you have overcome inertia. The Euro-spec G60 offers performance more in line with the looks and chassis behaviour of the car, but with a penalty at the petrol pump as with any car that uses forced aspiration. The stiffer chassis creates even higher levels of handling and roadholding than the 16V, but the ride is firmer too. On smooth German roads this is fine, but on some broken British A-roads, the ride can become a little jittery.

In terms of build quality and refinement, the Corrado is superb. The car feels hewn from the solid. The driving position will be familiar to those who have owned Sciroccos or even a Porsche 924/944! The difference is that you can get two adults into the back seats of the Corrado and its ability to cruise happily at three-figure speeds makes it a real Grand Touring coupe.

A VW Corrado car
An increasingly familiar sight as supply at last catches up with demand, the G60 Corrado is a true enthusiast's sports coupe and a worthy substitute for the now extinct 'entry level ' Porsche.

©Ian Kuah. This article was published with explicit permission from author Ian Kuah

OEM VW Avus Alloy Wheels

OEM VW Avus Alloy Wheels Image

Another fantastic wheel from Volkswagen, originally fitted to the Sciroco Scala and Golf Cabriolet. These wheels were originally named ‘Avus’ however over the years they have often been referred to as ‘Scala’ and also ‘Snowflakes’ in the USA where they were fitted to the Rabbit GTi and Quantum Synchro.

Technical Information:
VW PART No. 171 601 025H
ET 38