The aim was to design a concept car that could return an emissions figure of 90 g of CO2 per km. So when Opel achieved its goal it simply called the new vehicle G90 — and unveiled it at the Frankfurt Motor Show.
"Thanks to the use of aluminum and magnesium and other lightweight materials throughout the design, we were able to achieve a vehicle weight of just 750 kg (1650 lb). This is for a four seat car in the Astra size category," said Hans H. Demant, Member of the Opel Management Board, International Technical Development Center, when unveiling the car. The G90 is powered by a three-cylinder gasoline engine with an output of 60 hp (45 kW) and a displacement of 1-0-L. He said the combination of lightweight construction and good aerodynamics (0.22 Cd) enabled the car to record a fuel consumption of 3.88 L/100 km (61 mpg). "This puts us about one third below the fleet average pollution value of 140 grams per km that is planned for the European Union in the year 2008," he said. Herr Demant added that the figures demonstrated that independent of the powertrain, and without having to resort to exotic materials or detract from passenger comfort, it was possible to make "a reasonable priced car" with fuel consumption in the region of 3.0 L/100 km (78 mpg), "and one that is great fun to drive!"
The G90 is said to be capable of 180 km/h (112 mph). The forward engineering phase of the G90 started in 1997. It was decided that the engine should be a gasoline unit from the Opel production program, partly because it would be cheaper than a diesel and also because direct-injection gasoline technology had a lot of potential. The company chose the Corsa 973-cm3 unit. In the G90, it drives through a five-speed sequential-shift transmission with manual or automatic operation.
The G90 has a teardrop shape for good aerodynamics, which has necessitated a narrower rear track than that at the front — by 92 mm (3.6 in). The car has two individual rear seats instead of a bench. Its exhaust system is integrated into the body as a further aid to aerodynamics. But the most significant contribution to aerodynamic efficiency in the underbody area was to slope the rear floor upward at an angle of 6°. This results in a "diffuser effect," according to Opel. Together, the rearward sloping roofline and the low trailing edge of the tailgate combine to reduce rear surface area. The airflow above and below the car passes the body faster, resulting in less turbulence and reduced drag.
The use of lightweight materials for the car's construction, in turn, allowed additional savings in brake weight and other components such as steering knuckles. Aluminum suspension struts are used. The car's exhaust system has a mass of about 13 kg (28.5 lb) — some 6 kg (13.2 lb) less than a conventional system. It has five mounts.
Stuart Birch
Opel's low emissions G90 concept car weighs just 750 kg (1650 lb).
The G90 has a Cd of 0.22.
