Opel G90 Concept

You know what’s heavier than a 1999 Opel G90? Nearly everything.

At the Frankfurt Motor Show in 1999, Opel's four-seat family-car concept weighed just 750 kg. Better still, the G90 wasn’t some carbon-fibre science project with an unobtainium engine. Opel’s point was that an extremely economical car could be built with ordinary technology (and without making its occupants miserable).

Its name gave away the target: 90 grams of CO2 per kilometre. To get there, Opel fitted a 60-hp, 1.0-litre three-cylinder ECOTEC engine derived from the Corsa, attacking mass and aerodynamic drag to make it feel less terrible. G90 had a drag coefficient of 0.22 and could still reach 180 km/h.

Look closely, and its hatchback shape is quite strange.

Keep looking, and the strangeness starts making sense. The roof has two raised humps to preserve rear-seat headroom while keeping the body slippery. The rear is abruptly chopped off, its wheels are partially covered, even its exhaust was tucked into a smooth underbody.