F1's first turbo revolution

On March 16, a full grid of turbocharged Formula 1 cars will line up for the first time since the 1986 Australian Grand Prix. Prior to 2014, that was the only season in which F1's rules mandated the use of a turbo engine.

Since the end of 1988, when turbos were outlawed, F1 has been an exclusively atmospheric affair, but memories of the fire-breathing, howling 1.5-litre V6 and straight-four powerplants, capable in some cases of putting out upwards of 1500bhp, that dominated the sport during the turbo era have stuck.

These new-generation turbos will be almost unrecognisable as being from the same family.

They are refined pieces of kit with nowhere near the same peak power output, designed for maximum efficiency with green energy recovery and hugely complex management systems that make the previous generation of turbo engines seem like child's play.

But the old turbos weren't that straightforward, not by a long shot. Renault's audacious RS01, powered by a 1.5-litre V6 engine with a single Garrett turbocharger, first ran at Paul Ricard on March 23 1977.

It was not until 830 days later that its successor, the RS10, by then powered by a twin-turbo evolution of the same engine and driven by Jean-Pierre Jabouille, claimed the first victory of the turbo era. Considering a prototype test hack had started running in March '76, it was a long road.

Legend has it that the idea of a turbocharged grand prix car was derided at the time. It was in some quarters, but for all the mockery of what some saw as doomed French ambition over know-how, there were plenty who realised the potential.

Rivals were already wary before the turbocharged Renault arrived © LAT

And when Jabouille outpaced everyone except Jacques Laffite's Ligier in a test at Dijon in June, a few weeks before the car's debut in the 1977 British GP, there were genuine fears that it would turn up and not so much move the goalposts as blow them away. The car had a lot of problems, but Jabouille's lap of 1m12.89s created a huge stir.

"I think I could have gone easily around in a 1m12.5s," reckoned Jabouille. "But I always had a misfiring problem and never managed more than two or three continuous laps."

There was a belief that compressor engines would require the kinds of advanced fuels legal in the 1950s to be made to work, something the regulations demanding broadly commercial road car pump fuel prevented.

But others realised that the 2:1 equivalency ratio, which allowed 1.5-litre forced induction engines to take on three-litre atmospheric engines, was potentially not so equitable.

As its starting point, Renault had to use the two-litre V6 engine it had been racing in sportscars and Formula 2, and the two options on offer were either to convert it into a 1500cc turbo or an unorthodox three-litre W9 atmospheric engine. The choice of the blown engine was straightforward, especially as the cast-iron block gave it an architecture that could be expected to stand the rigours of turbocharging.

Once it became clear Renault intended to build a turbo engine, the lobbying began to ban such units among the existing teams - not the actions of a paddock that did not realise the potential of a well-executed turbo engine.

Renault's commitment didn't waver amid early troubles © LAT

"The alternative to the hitherto universal three-litre atmospheric engine was previously thought to be hopelessly uncompetitive," wrote AUTOSPORT's legendary technical editor John Bolster on the eve of the car's debut at Silverstone.

"But suddenly it is assumed that it will look so fast that the old guard will look silly, and so expensive that the sponsors will turn and flee."

The fears of instant dominance were allayed by a troubled debut at Silverstone, with Jabouille qualifying 21st, 1.62s off pole.

Making the grid was an achievement in itself given difficulties in practice. The car retired with a turbo failure after 16 laps, Jabouille having run no higher than 16th. It was the start of a long and painful process to make the car competitive and reliable.

Controlling temperature was a big problem and producing pistons and turbos that could withstand the rigours of high boost pressures required vast and costly effort.

It was a huge challenge for what was a small team. Bernard Dudot spearheaded the project along with Renault technical director Francois Castaing and F1 project leader Jean-Pierre Boudy. But they had only an eight-man team.

Fortunately, Renault president Bernard Hanon, who had been sold on the idea of the turbo, supported the project to the hilt in a way that, according to Dudot, "would not happen today".

Performance, or to be more precise, peak power, was relatively easy to achieve. Immediately, the turbo engine eclipsed the peak power of its normally-aspirated rivals, but this was not enough to make it competitive.

Reliability was a massive issue because the technology simply was not available and both Renault and their suppliers were struggling to deal with problems created by running high levels of boost on an engine that, according to the understanding of the rules at the time, had to run on roadgoing pump fuel.

Watkins Glen 1978 was Renault's breakthrough race © LAT

But as time went on, the engine became not only increasingly powerful but increasingly reliable. Part of this process was based on Elf, at huge expense, developing its fuel with additives such as anti-detonation agents that kept temperatures under control.

"At first, we achieved 550bhp with 2.5 bar boost," explains Dudot. "But due to the turbo lag compared to the other competitors it was not sufficient. A first step was 600bhp with around three bar and progressively the boost was raised to increase power 30-50bhp each year up until around 1500bhp with 5.5 bar with Lotus and Ayrton Senna."

Four-figure power outputs were some way off in the early days, though significant progress was made in the first 12-18 months. Power continued to climb, allowing Jabouille to qualify sixth for the third round of 1978 at Kyalami in South Africa, but it wasn't until the United States Grand Prix in October that the car finally scored thanks to his fourth place.

The following year, Jabouille won the French GP with both a new car and an engine that featured two turbos, which played a big part in ameliorating the lag problem that was initially measured in seconds.

It's a race that has gone down in history for the astonishing battle between Rene Arnoux and Gilles Villeneuve for second, but it was far more significant as a watershed for F1. The turbo engine was now capable of putting out vastly more bhp than the normally-aspirated powerplants and reliability was coming.

Ferrari was also pushing on with work on its turbo, which was not as well-advanced in 1977 as Enzo had suggested. The Scuderia opted for a 120-degree V6, 30 degrees wider than the Renault powerplant, which made it easier to package the engine ancillaries, including the turbocharger.

Villeneuve starts Ferrari's turbo era at Imola in 1980 © LAT

The engine briefly appeared in practice at the 1980 Italian Grand Prix in the hands of Villeneuve, but it wasn't until the start of the following season that Renault was joined by turbo rivals, with both the Ferrari 126CK and the straight-four-engined Toleman. The turbo era had truly begun.

Others soon joined the revolution. BMW was working on an engine that would debut in the back of the Brabham BT50 in 1982 and was soon setting the standard for turbo performance.

Honda came in with its V6 turbo, initially with Spirit in the 1983 Race of Champions and then with Williams. McLaren commissioned a TAG-bankrolled Porsche unit that first appeared late in '83 and went on to dominate the following season.

Technology was also advancing apace and Renault introduced electronic injection in 1983. But other manufacturers had started to seize the initiative. As well as improving the driveability of the engines, more complex engine management systems made the cars more reliable and better able to harness their power.

Combined with major innovations in fuel development, exemplified by the 'rocket fuel' that powered the BMW powerplants in this period, it meant the atmospheric engine didn't have a chance.

"The fuel injection engine was first managed with a mechanical Kugelfisher pump having only two parameters: boost and throttle position," says Dudot.

"The mixture was very inaccurate. The first electronic development was made with Renix, a Renault subsidiary. It was not successful. Magneti Marelli was too much involved with Ferrari and Renault did not want to be involved with the same supplier as a direct competitor.

"It was an error. Two years later, much progress had been made with the Marelli device: turbo lag, temperature control and piston reliability."

When Michele Alboreto won in Detroit for Tyrrell in 1983, it was the last time that a normally-aspirated car would do so against one with forced induction. For the next five seasons, turbo engines ruled the roost despite measures designed to make it a fairer fight.

Alboreto's Tyrrell-Ford managed to defeat the turbos one last time in Detroit © LAT

In 1984, a 220-litre fuel limit was introduced, reduced two years later to 195 litres. Regulations limiting boost pressure to four bar in '87 came in. For the final year of turbos in 1988, just 2.5 bar boost pressure and 155 litres of fuel were permitted but still swept the board, with McLaren-Honda annihilating the field that year.

Renault never managed to win the world championship it coveted, but without its pioneering spirit, it's possible the turbo era might never have happened at all.

That it did is testament to the innovation and hard work of the company, as well as the faith the its top brass had in the project during those early days of struggle and embarrassing retirements.

This week's AUTOSPORT magazine is a 1980s F1 turbo special, with a host of features revealing the era's untold stories.

HOW A TURBO WORKS
By Craig Scarborough

Like any engine, an F1 motor needs fuel and air to produce power - the more of each you can put into the engine the more power it can produce. In reality you can pump more than enough fuel into the engine, so the limitation is how much air you can get in.

A turbocharger helps produce more power as it forces more air under pressure into the engine. Essentially, the turbo is an exhaust-driven air pump.

In a turbo engine, the exhaust energy that is usually wasted as it exits from the tailpipe is fed into the turbo instead. This spins a turbine wheel inside the turbo and the exhaust flow then exits through a tail pipe having had most of its energy recovered by the turbo.

The exhaust turbine is in turn connected by a shaft to another turbine that sucks in and compresses air. It's this compressed air that is fed back into the engine. The pressure that the compressed air is at is known as boost pressure.

For F1 in 2014 there is no limit on boost pressure, unlike the latter years of the 1980s turbo era.