The first oil crisis, during which the price of a barrel of crude oil went up from US$3 to $5.12, forced automakers to find new ways of improving fuel consumption. At Renault, George Douin supported the idea of what later became known as “GTLisation”. This meant boosting engine capacity while at the same time increasing gear spacing: by running more slowly, not only did the engines become more fuel-efficient, but also quieter, cleaner and more robust. In France, the problem of fiscal rating (which is proportional to engine size) was solved by the introduction of a law that took gear spacing into account when calculating the amount motorists had to pay. It was Renault that put forward this idea.
As a result, in February 1976 a new version of the Renault 5 GTL with greatly improved fuel consumption was added to the range. It also offered more features – especially tough new protective side mouldings that were very useful for city driving. This soon became the best-selling version of the Renault 5.
Meanwhile, discussions began in 1975 about the energy constraints of the future. The prospects that emerged were relatively bleak. Another oil crisis was expected in 1979 – and it would take at least that long to come up with effective measures to counteract it. It was decided to optimise the fuel consumption of the Renault 5 GTL. Because the car was such a “lightweight” at just 785 kilograms, the engine capacity was reduced from 1289cc to 1108cc, which also had the effect of lowering the French fiscal rating to 4hp.
While planning a major campaign to relaunch the Renault 5 in mid-1979, Renault took the economic risks of the future into account. It was agreed to combine the R5 TL and GTL engines into one 1108cc unit.
Early in 1979, history proved Renault right in its gloomy forecast (although chance also played a part…): the second oil crisis, sparked by the Islamic revolution in Iran, pushed the price of crude up to US$13 a barrel. Even before the new versions of the Renault 5 were launched, television newscasts gave plenty of free advertising to those champions of fuel efficiency: 4.9l/100km at 90kph, 6.8l at 120kph, and 6.3l in the urban cycle (28% less than the previous version!).
The launch of the 1980 vintage of the Renault 5, which also included a new five-door option and a restyled interior, was a huge success. That same year, it became the European market leader with penetration of 5.37%, which gave Renault total market share of 14.8% (up 1.47 percentage points) and put it ahead of its rival PSA. In France the Renault 5 snatched 16% of sales (compared to 10% the year before) and Renault obtained market share of over 40%.