The surprising secrets of F1 fuel

Given how hard F1 works to innovate, it would be fair to assume that the fuel in Formula 1 cars is super-secret and nothing at all like the stuff in your own car.

In actual fact, it’s incredibly similar to the unleaded you use – not identical, but not far off. However, it’s not always been this way.

The story of F1 fuel innovations is punctuated with banned substances and changing technologies.

The bad, mad old days

In F1’s formative years, fuel tanks were filled with appallingly unpleasant mixtures.

There was a lot of benzene used, for example. It’s a high-octane substance and, as such, can improve an engine’s power output.

There is still a little benzene in modern car fuel, but it’s less than 1 per cent, and with good reason.

Benzene is highly flammable and, although it occurs naturally in crude oil and natural gas, it is a carcinogen.

It gets into your body through your lungs and skin and exposure to significant levels can leave you feeling sick, dizzy and tired. It’s nasty stuff and, if you hang around it for long enough (as a mechanic, for example…) then there is a serious risk of blood disorders such as leukaemia and anaemia.

As well as benzene, early F1 racers used alcohol in their tanks and aviation fuel as well.

Extreme blends of high-density fuels – which were heavier than water – were common.

Inventive as these fuel cocktails were, they were incredibly dangerous not just to humans but, on occasion, to the cars themselves.

So corrosive were some fuel mixtures that, after a race, the engine had to be drained then rinsed with regular road-car petrol, to prevent the race fuel from eating away at the metal components.

Try, try, try not to die

In terms of innovation, the best stuff has tended to be kept a secret, and this remains the case to this day: fuel is big business, and one company’s recipes are not any other company’s business, although this hasn’t stopped snooping.

What do we know about the fuels that have been used in F1, and how they have changed as scientists have found improvements and dealt with rule changes down the years?

Until late 1957, it was a free-for-all. One fuel recipe for Mercedes, for example, was 45 per cent benzene – a pretty scary start for any such recipe.

Another 25 per cent was methyl alcohol. Unless you’re a chemist, methyl alcohol may sound as safe as any other sort of alcohol.

It’s not; it’s great as a fuel, and it also works well as a solvent and in antifreeze. But it’s a killer – drink just a tenth of a litre and death is likely. Consume even a small amount and, as the methyl alcohol degrades into formic acid, you’ll go blind.

And that was a quarter of the fuel mixture.

Almost as much, 23 per cent, was aviation fuel, which itself has changed over the years, in no small part to lessen the risk of accidental fire.

The remaining 7 per cent was acetone (3 per cent), nitrobenzene (2 per cent) and a further 2 per cent which has remained a secret.

Money talks

The crazy chemistry of such fuel was all very well on a race circuit but it had little benefit in the real world.

Oil companies pressured F1 to move to a less extreme fuel formula, so that the technology was more relevant to ordinary consumers, and also because the risk to life was considerably less.

In 1958, aviation fuel with a 130 octane rating was mandated. In the years that followed, more and more restrictions on fuel ingredients were introduced, and oil companies had to work harder and harder to make their fuels the best.

In 1992, F1 fuels were restricted to being created from a little oxygen, a little nitrogen and, otherwise, only hydrocarbons.

There was to be no alcohol or exotic power-boosting additives, and F1 fuel had to meet EU health and safety standards.

In many ways, this simplified the challenge facing fuel innovators. Before these rule changes, they were experimenting with more than 300 different fuel mixtures in a season.

After the changes, much more focus fell on the effects of altering the proportions of fuel ingredients, rather than introducing new ingredients.

The art of innovative policing

An F1 team can get through 200,000 litres of fuel in a season, including testing, and the blend can be tweaked to suit different circuits and racing conditions.

The art of the fuel specialist is to master the various trade-offs that arise from altering a blend.

For example, you may want to extract a little more power from the fuel mixture but the trade-off may be poorer low-end performance, increased engine wear or poorer fuel consumption.

The authorities have had to keep on top of this and have introduced all manner of checks over the years.

Since 1995, the FIA has received fuel samples for analysing in advance of a race. This sample allows them to create a fuel ‘fingerprint’ and, at any point, inspectors can ask to check the fuel a team is actually using to ensure it has the same fingerprint.

Discrepancies lead to disqualification, even if the cause was accidental.

What does fuel do?

Obviously, it combusts. But the way in which it combusts can be the difference between success and failure.

When a fuel mixture is being blended, altering the recipe can have an effect on more parameters than how much power is being sent to the rear wheels.

For example, the turbo-era cars perform best when the fuel mixture is lean – more air, less fuel. So fuel has to be able to burn in a stable fashion despite the lean conditions.

Managing the temperature of the engine is of critical importance and, again, the fuel blend can have a significant impact.

Fuel needs to burn almost instantaneously, without creating the tiny explosions we call ‘knocking’ in an engine, which are both inefficient and destructive.

Fuel needs also to have lubricating properties, and to prevent deposits forming on the engine surfaces.

And all this needs to be accomplished with a blend that is 99 per cent the same as the fuel in your family car.

Back in 2011, Ferrari and Shell compared road fuel with F1 fuel in a Formula 1 car.

Fernando Alonso did four laps with each type and, perhaps unsurprisingly, the race fuel allowed him to post a lap that was 0.9seconds quicker than with the road fuel.

However, the road fuel delivered a faster top speed, albeit at the expense of acceleration.

When it comes to fuel, innovation these days is all about trade-offs and tiny changes, whatever it takes to shave a fraction of a second off a lap time, lap after lap. It may be an invisible technology, but it’s no less innovative because of it.