Fuel and lubricants – AUDI QUATTRO RALLY CAR MANUAL

Fuel and lubricants

Motor sport requires the development of motor and transmission fluids to’ keep pace with the performance of the cars. Then, as now, motor manufacturers tended to work with their respective global OEM lubricants provider,

as they could negotiate a good discount on the millions of litres needed for factory fill and aftermarket servicing needs.

Audi’s global lubricants partnership was with Castrol and so it was the British brand that appeared on the cars… in the world championship at least. Audi UK and Audi South Africa had deals with Shell, so its branding appeared. Meanwhile Audi France had a deal with BP for fuel and lubricants, which resulted in Michele Mouton driving a black Quattro with green and yellow stripes in 1981, and carrying the BP shield on her overalls – even when Castrol branding was on the cars.

Fuels were a different matter entirely, however. Today, a standard ‘control’ fuel is provided for every series except Formula 1 but the 1980s are remembered as a time of innovation in fuel composition. While the aerodynamicists and engine builders stood in the limelight, behind them were the chemists engaging in a battle unseen by the public and unheralded by the press.

The turbo era was unleashed by Porsche in 1972 under Ferdinand Piech, inspiring BMW, then Renault, Saab and Ferrari to follow suit. As more and more power was found, and greater temperatures and pressures resulted, the problem became one of detonation – losing control of combustion and suffering engine failure as a result.

Legend has it that it was BMW engine designer Paul Rosche who, in trying to get more power from BMW’s turbocharged Formula 1 engine, went to BASF and asked for the formula for fuels that had been developed for German high-altitude fighters during the Second World War. The story continues that once this special brew was mixed it was run on a dynamometer and ‘boom!’, 1,450 horsepower appeared.

The mystique of a ‘Nazi super-weapon’ has been part of popular culture ever since Captain America comics were invented, and nobody likes a good rumour better than motor sport folk. In fact, the power of the Luftwaffe’s fighters was enhanced by blowing a mix of water/methanol into the supercharger when flying at low altitudes and nitrous oxide when at altitude. Alfa Romeo’s supercharged grand prix cars used the water/ methanol trick but there is no evidence of similar systems being used in the 1980s.

The fuel formula that BASF located was of Second World War origin and it was one of many similar blends developed by all of the fuel providers in motor sport during the turbo era. FISA specified that fuels had to be of the same octane rating as commercially available pump fuel but said nothing about their composition. The chemists laboured to come up with a very dense fuel that burned relatively slowly in the cylinders, allowing higher compression ratios, more boost and thereby more power. This was done without altering the octane rating by creating mixtures that included benzene, toluene, xylene, trimethyl-benzene and butane.

Most fuel companies prefer not to talk about their 1980s racing blends today, because the substances involved are extraordinarily harmful to humans. The heavy smell that hung over the paddocks and service areas of the time attested to their presence, however – as did the number of team members’ shoes that melted if any was spilt.

Any rubber and plastic parts in between the filler neck and the exhaust would therefore need to be changed from one event to the next. Even in spite of these measures, it is widely held that Henri Toivonen and co-driver Sergio Cresto had been overcome by fumes leaking from the fuel tanks before their Lancia S4 plunged off the road on the 1986 Tour de Corse. The use of these highly specialised fuels was finally outlawed in the early 1990s.

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