Ten key facts about F1's 2014 fuel war

The initial focus of Formula 1's radical new era was always going to be about the engines.

With new 1.6-litre turbo regulations arriving to shake up the sport and kick it towards a more relevant future, work done by Renault, Ferrari and Mercedes was quite rightly going to have the biggest impact on the outcome of the championship.

But as the races have developed, and the strengths/weaknesses of the car packages have been exposed, there's an intriguing new battleground opening up in F1: fuel.

For years now, the efforts of F1's fuel companies had been pretty much under the radar. The diminishing returns of extracting performance from the old V8s meant that dramatic gains from petrol were a rare thing.

But the new engines, the return of turbos, the power of energy-recovery systems and a new type of racing have changed that.

How a team's fuel performs is directly affecting its performance on track - which is why teams are pushing their suppliers like never before.

As Red Bull boss Christian Horner explains: "Fuel is a key area of development and something that all the fuel suppliers are working on very hard. It's an opportunity for fuel suppliers to make a difference."

So here are 10 things you need to know about F1's new fuel battle:

FUEL IS AS DIFFERENT AS ENGINES THIS YEAR

Shell engineers at work for Ferrari

It doesn't take a genius to realise that F1's current turbo engines are completely different to the naturally aspirated V8s they replace.

But what hasn't been so obvious is that what goes inside them has changed completely as well.

Shell technology manager Guy Lovett said: "The regulations are the same, so the envelope in which we have to operate hasn't changed since last year.

"But the fuel requirement of a highly boosted, downsized turbocharged direct-injection engine is very different to a naturally aspirated 2.4-litre V8. So within the detail those are quite different."

FUEL WAS DESIGN ELEMENT OF ENGINE FOR THE FIRST TIME

Petronas COO Eric Holthusen has seen it all during more than two decades of work in the fuel-and-lubricants industry.

It says much about the new F1 that this leading industry figure says he has noticed things this year that he's never seen before - including an F1 engine and its fuel having to be created together.

"Fuel has always been important in the F1 environment, but with a new engine and a new fuel it means there is hardly anything you can take from the past," he said.

"And it's not the fuel alone - it's a combination, because the fuel is tailor-made for a specific engine. We've been working on it with Mercedes for almost two years.

"I've been in the business for more than 20 years, and I can't remember that it's ever happened that, from the conception of the engine, the fuel was a design element."

NEW ENGINES HAVE POSED A PROPER CHALLENGE FOR FUEL SUPPLIERS

Handling what goes on in here is not easy

The biggest change the fuel suppliers have faced this year is dealing with the problem area of 'detonation' - or engine knock as it's more-commonly known.

Detonation is an uncontrolled explosion inside the cylinder, which not only hinders peak performance but can also cause a shockwave that damages the internal components of the engine.

Turbo engines are much more susceptible to this, because they have higher compression rates and rev much lower. That means there's more time for a second combustion source to develop.

Although fuel providers are able to control the risk of detonation through increasing the octane levels, there's a balance to be found because the peak power doesn't necessarily come with the highest octane level.

Holthusen said: "There's an optimal octane index, and you have to find that point - it takes a lot of testing. If you go higher in your RON [octane level] you could see a decrease in power. It's about optimisation."

IT MATTERS HOW FUEL ACTS WHEN TURNED INTO A SPRAY

As well as being turbo engines, this year's F1 power units are direct-injection, meaning the fuel is injected straight into the chamber rather than being mixed with air beforehand.

Holthusen says how the fuel behaves in the 'atomised' state is now decisive in terms of performance.

"We have to inject the fuel into the compressed air, like in a diesel engine, so the quality of the combustion is very much governed by the atomisation of the fuel.

"You want to have small droplets, so that's very important. The surface tension of your fuel has to be lowered to get maximum atomisation to have good combustion and get the maximum out of the fuel."

HEAT DEMANDS HAVE INCREASED

Packaging a 2014 F1 car's internals is tricky for all involved © XPB

F1 engines have always run hot, but the turbo engine, allied to the unique demands of new energy-recovery systems that generate their own heat, means keeping things cool this year is much more difficult.

With the key to keeping an engine within its perfect operating window being how well you can get the oil cooled, that's meant a bigger challenge for internal lubricants.

Holthusen said: "It was a big step in terms of heat management. We had a 20 per cent increase in thermal load on the lubricant compared to the V8 engine."

The only way to cope has been with synthetic fuels.

PUNCH PER POUND IS THE KEY TO SUCCESS

There was a time in F1 when the only thing that mattered was trying to unleash the maximum power possible, resulting in some pretty exotic brews in the past.

But tighter restrictions from the FIA about what can be used as fuel - allied to the maximum limit of 100kg of fuel for a race - means that the demand is now very different.

As Lovett explains, it's about extracting as much energy as possible from a set amount of fuel.

The Petronas labs develop the fuel for championship leader Mercedes

"The 100kg rule means we have to get as much energy as possible into the fuel," he said. "You want as many calories in the car as possible to give it energy, as that's the only energy going into the car.

"But any component in the fuel that's good for octane is not so good for energy and vice versa, so there's a negative correlation.

"The key to success and to an optimum fuel is balancing the octane for performance and anti-knock, and the energy content - and trying to find clever, innovative ways of boosting performance. That really is a huge challenge."

BETTER FUEL IS IMPORTANT FOR ELECTRIC ENERGY TOO

Improving the bang for the buck from fuel is not just important for boosting the performance of the internal-combustion engine.

There are now double benefits from progress in this area, because it can have a big boost in terms of the recovered electrical energy available to a driver.

A more-efficient fuel doesn't necessarily mean less fuel can be put into a car - saving weight - because the excess fuel available could simply be used to boost F1's new, more-powerful energy-recovery systems.

Lovett said: "The engines are homologated, so one of the only things that can be changed is the fuel and the oil. That's an opportunity to give more performance to the car during the season.

"With the MGU-H, improving performance just in terms of the combustion means that if you're able to put more energy into the fuel then you can exploit that by potentially generating additional heat, which can be made into recoverable energy."

FUEL EFFICIENCY CAN NOW BOOST STRAIGHTLINE SPEED

Fuel is playing a bigger part in deciding straightline speeds © XPB

Not so long ago, the efforts of the fuel companies in improving efficiency wouldn't have made much difference to the engine manufacturers themselves.

It merely manifested itself in the ability to run with lighter fuel loads, which reduced the overall weight of the car.

Now though, the car makers are pushing the fuel companies to improve efficiency, because their success relies upon it.

Renault engine chief Rob White said: "It [fuel economy] might in a previous era have been a second-order effect, but it's now up there with the headline items.

"Fuel-consumption improvement can directly influence end-of-straight speed quite a lot.

"I don't want to overegg the pudding, but if you gain sufficient fuel to be able to spend a little bit of fuel on generating electricity, it opens the door to an energy deployment which is more interesting to the drivers.

"It can be perhaps a biggish difference on end-of-straight speed, a noticeable difference on lap time, and overall quite a small change in fuel consumption. But this is a good example of how F1 is. It's a multi-parameter optimisation that we're looking for."

FUEL SPREAD DIFFERENCE CAN BE MASSIVE

Detailed GPS analysis of engine performance this year has highlighted that fuel could be making a pretty big difference to engines.

Red Bull technical chief Adrian Newey first pointed this out earlier this year when he suggested that variation between cars with the same engine on a straight could only be explained by fuel.

Identical engines might perform differently with different fuels © XPB

"I think you'll find within an engine, depending on what fuel it uses there can be very significant differences," he said. "That can also create differences.

"We certainly can see that in our own GPS analysis between our rivals that some appear to have significantly more power than others, even though they have the same engine."

Insiders have suggested that the variation between fuel makers using the same engine could be as much as 30bhp this year.

Lovett does not rule out some suppliers needing to play catch-up, but does say that the rate of progress means variations could be quite big.

"We're seeing bigger steps than we have seen in the past from the V8 - that's clear," he said. "We're on the upward slope of the development cycle and typically in any development cycle we make big steps early. And that's what we're doing right now."

F1 HAS GOT ITS TECHNICAL-INNOVATION MOJO BACK

One of the intentions of F1's switch to fuel-efficient engines this year was to make it more relevant to the future direction of road cars.

Having racing technology flow back through to the road-car industry has long been important to F1 - and it's something that the sport is doing in spades this year.

Even from the fuel perspective, what the companies are learning this year is going to flow all the way back to improving what comes out of pumps in years to come.

Lovett said: "The technology that we're working on here with Ferrari is directly relevant to road-car technology and the ability to transfer the knowledge, technology, data and expertise from the Ferrari F1 programme to our road-going programmes - that's one of the most important aspects of why Shell is in F1."

Holthusen added: "The people who work on the F1 lubricants and F1 fuels also work on road fuels and road lubricants, and I see it also as a motivator for the people. They all are passionate about working for F1 but, at the same time, they work on the day-to-day lubricant that we use in our cars."