There was a time when talk of a petrol war in Formula 1 was limited solely to that great period in the 1980's when 'rocket fuel' was the name of the game.

The quest to get the previous generation of turbo engines to 1000bhp and above resulted in chemistry boffins pumping additives likes toluene in to the fuel.

With garages smelling like the paint thinning products these solvents were also used in, F1's rocket fuel era brought decent gains on track – and many a tear to the eyes of mechanics off it.

Rocket fuel ban

Such brews have long been outlawed, but that has not stopped F1's fuel suppliers from digging deep in to the detail of the chemical composition of their products to help the current manufacturers along.

And, as Mercedes showed at the Italian Grand Prix with a new 'development' engine that was trialled for the first time, fuel is no longer something that is just pumped into it. It's very much its life and blood now.

For the change of Mercedes specification for Monza was led by a desire to explore a new fuel development direction for 2016 – something the design of new engine components worked exclusively with.

Put simply, the new fuel in the old engines would not have delivered the step, and neither would the new engines running the old fuel. But together, they did.

As Chan Ming Yau, Petronas' fuel technology manager, said: "There was a time when engine development triggered a change of fuel. This time around, I would say it is now done together.

"The new spec introduction at Monza speaks for that; new spec engine and new fuel. It now goes hand-in-hand."

Changed relationship

F1's new turbo regulations, and specifically the 100kg petrol limit per race, has put a premium on engine and fuel supplier working much closer together.

Maximising the bang for your buck (combustion efficiency) is the key to success; and it was no surprise to find out last year that the foundations for Mercedes' recent domination was laid through it developing its engine hand-in-hand with fuel supplier Petronas.

For the Malaysian company, the challenges of delivering in F1 are far greater now than they would have been mixing those chemicals together in the rocket fuel era.

Eric Holthusen, COO of Petronas International, told Motorsport.com: "It is definitely the case.

"We are much more restricted because you cannot use anything that is nasty any more – so what you have today is very close to the products on the road.

"You have to use the same components and put them together in a clever way, which gives more power, better acceleration and better economy on the engines.

"The Mercedes technical team and our technical team work hand-in-hand. It is not that the engine is developed and the F1 team goes; 'here is the F1 engine, give us the fuel'.

"Today, there is a co-operation right from the start and the team work together to push themselves to a point that one engine can only run on the fuel that is designed for.

"So if you would give our fuel today that is in the Silver Arrows to any of the other teams not running Mercedes engines, they would not get this performance benefit.

"It is so core engineered, the hardware and the fuel. It is hard to separate."

For Mercedes, producing the benchmark F1 engine has come as the result of listening to the requirements of the fuel supplier too.

Mercedes motorsport boss Toto Wolff said: "You have the chassis side and the power unit side, and because the power unit is so complex all components have to work with each other.

"You cannot from Petronas' perspective have a super fuel which doesn't work in that particular engine, or at that particular efficiency or power deployment. It's about three performance topics: fuel (oils and lubes too), engine development and chassis development."

More than fuel

Maximising power delivery and combustion performance of fuel is not the limit of Petronas' involvement.

Holthusen believes that there is great scope for performance improvements to come now with better gearbox lubricant, and in ERS cooling fluid that could have knock-on improvements for aerodynamics.

"The fuel seems to take always centre stage, but if you look at the car today: there are five fluids that come from Petronas: the fuel, the engine lubricant, the gearbox lubricant, the cooling fluid for ERS and the hydraulic system.

"A lot of this performance potential we have neglected because we have focused on the engine lubricant and fuel first. But we have recently had technical meetings with the team – looking at the gearbox and how much more efficiency can we get out of the gearbox lubricant.

"Also, how can we help aerodynamics of the car by having a better ERS cooling? Because if you have better heat transfer, the chassis team can reduce the surface of the heat exchanges which improves the aerodynamics – which then makes the car faster.

"Things in the beginning that you would not think of, like gearbox oil or cooling of ERS making the car faster, they can.

"While the new engines are getting more mature, by no means is the hardware or fluids mature. So there is always more that we can squeeze out."

Gains still coming

What Mercedes showed in Monza, with a performance step that rival Christian Horner called 'frightening', was that rapid progress is still possible with these regulations.

Mercedes has not commented on speculation that the new specification has delivered a 40bhp boost, but Holthusen admits that efforts are still flat out to find decent gains.

"It gets harder. It definitely gets harder," he said. "The low hanging fruit has been picked, that is for sure.

"We are getting pushed by the team, and the team gets insights and ideas from what we have. We will not see the quantum leaps we saw in the beginning, but we have continuous improvement and you have to watch what the competition does.

"Mercedes watches the other teams, we watch the other fuels and lubricants and try to find out what they are working on, because components we probably had through clever research last year become available to them as well. It doesn't go unnoticed.

"You have to keep working on new things."

That never-ending quest for technical improvement is what F1's DNA has long been about: and it's what ties the rocket fuel era to today's petro-chemical science even though they are worlds apart.