Twin-Jet VW Jetta

Twin Jet VW Jetta
The Twin-Jet Jetta was painted a lurid bright yellow and wore a modified BBS body styling kit.

The second surprise to emerge from the VW Motorsport workshops was their answer to the Audi quattro in the form of a twin-engined Jetta. This prototype, affectionately known as the Twin-Jet, was painted banana yellow with a colour-coded grille and had a headlamp set-up similar to the US-market version. A body kit with integrated front spoiler and over-bumper sections that blended into the extended wheel-arches gave the car a more purposeful look and covered the 205/60VR-13 Pirelli P7R tyres that were supported by 6J x 13in ATS alloy wheels. The Twin-Jet was the brainchild of Klaus-Peter Rosorius, Head of VW Motorsport since 1972, and Kurt Bergmann from Vienna, one-time builder of all-conquering FV cars. The idea was a bit of a wild card in the pack, but Rosorius was determined to pull it off as a good PR exercise even if it did not work as a rally car. Because the Jetta has a transversely mounted engine, it was necessary to have another complete drivetrain package at the rear, whereas had the engine been mounted north-south, a single gearbox could have been used. In the event, the underbonnet structure from a second Jetta was spliced in to a reinforced boot area. This gave the car a suspension identical to the front save for the a use of Heim-jointed tubular lower arms in place of the front-end’s pressed steel arms. A new heavy-duty anti-roll bar was made up for the rear to balance things out, and a pair of front ventilated discs joined the rear axle assembly. As things were arranged, you could choose from front drive, rear drive or four-wheel drive, so a brake proportioning control was mounted on the transmission tunnel. The handbrake had hydraulic actuation.

The two power plants were standard 110bhp 1,588cc GTI units and the Twin-Jet thus had a combined thrust of 220bhp at 6,100rpm and 202lb/ft of torque at 5,000rpm. The ignition and fuel systems ran independently of one another, but a large capacity radiator served both engines and this was supplemented by an additional electric fan at the rear. While the gearboxes were standard Jetta GLI close-ratio five-speeders, the final drive was raised from 3.90:1 to 3.70:1 to make full use of the greater power in top speed terms. A limited-slip differential was incorporated into the rear transaxle. The kerb weight of the car was just 2,3101b compared to the 2,0461b of a normal Jetta GLI. With superb traction in 4WD configuration, this gave the car very impressive performance and, in truth, the car worked out far better than its builders had hoped. In 12,000 development miles, covered in just a few months after it was built in 1981, the Twin-Jet spurred Rosorius into giving the go-ahead for a twin-engined version of the just-launched Scirocco Mk2.

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