What is it?
A hyper-economical carbonfibre and gull-winged two-seater that is the culmination of more than a decade of engineering effort at Volkswagen. This started with Ferdinand Piech’s (now chairman of the VW supervisory board) turn-of-the-century vision of building a production car capable of covering 100km on one litre of fuel, or 282mpg.
The first concept was the 2002 L1, which combined a carbonfibre body, tandem seating, a side-hinged canopy and a single-cylinder, 8bhp, engine. The car weighed just 290kg. The L1 was demonstrated by Piech, who was then VW Group boss, and the company claimed fuel economy of 0.99-litres per 100km, or 238mpg.
The second-generation L1 was shown in Autumn 2009. This featured hybrid transmission combining a two-cylinder diesel engine and an electric motor. The problem with making the L1 production-ready was less the uncivilised tandem seating and aircraft-style side-hinged roof canopy and more the issue of it meeting crash test requirements.
Less than two years after the second-generation L1, VW showed the XL1 in the form of a series of driveable prototypes. VW engineers had taken a huge leap with the ‘one-litre’ concept by retaining the two-cylinder hybrid drivetrain but completely rethinking the body design.
Bringing the story right up to date, the final design is based around a supercar-style carbonfibre reinforced plastic (CFRP) monocoque passenger cell, with the passenger seat staggered behind the driver seat. This clever arrangement reduces the amount of shoulder room needed, allowing the body to be as narrow as possible for aerodynamic reasons. Crash protection front and rear is provided by large extruded aluminium crash boxes and the mid-mounted powertrain is also hung off the rear aluminium subframe. The whole assembly weighs just 230kg.
To make for easier access across the wide sills, the XL1 has large gullwing doors which cut right into the roof. If you end up upside down in the XL1, explosive bolts release the gullwing doors. The XL1 is 3.88m long, just 1.65m wide and 1.15m tall – which makes it 10cm shorter than a Volkswagen Polo, less than 20mm narrower but nearly 30cm lower.
These dimensions are, of course, at the maximum points. In the flesh, the XL1 looks tiny, not just because it so low, but also because the body tapers away to the classic teardrop shape with the rear wheels enclosed by the body. It has a Cd rating of just 0.189 - surely a world record for a production car.
The front suspension is made up of double wishbones, the rear a ‘semi-trailing link system’. The brake discs are made of lightweight ceramic and the wheels are magnesium. The front wheels are almost motorcycle-slim at 115/80 R15 and the rears 145/55 R 16.
Behind the passenger cell is the two-cylinder hybrid drivetrain. Effectively half of an existing 1.6-litre turbo diesel, tweaked and fitted with a balancer shaft, it develops 50bhp and the electric motor provides 27bhp. Both drive through a seven-speed DSG gearbox. The 5.5kWh lithium-Ion battery pack is mounted in the front of the car, in the void ahead of the passenger’s feet.
The XL1 can run on diesel only, electric only or, in boost mode, a combination of the two. During boost mode the two motors generate a maximum of 68.3bhp and a maximum of 103lb ft of torque. The XL1’s top speed is limited to 99.4mph and it can hit 62mph in 12.7secs.