Power unit: Renault's 2014 engine plus ERS and ancillaries

Certainly it's the biggest since 2009, when KERS first appeared and the majority of the current aero rules were introduced. According to Sky Sports F1's Martin Brundle, "It's right up there, I would have thought, with banning turbos in that era". It's now 25 years since the era to which Martin refers passed F1 by, yet the new rules see the sport going back to the future.

But only up to a point. Yes, turbos are back - but not with a vengeance. The 1200bhp fire-belching monsters that Brundle and his contemporaries grappled with back in the 1980s are certainly not on the agenda. Times have changed, attitudes have shifted, and what's to come reflects as much.

In short, F1 is going green. The 'revolution' which started with the introduction of KERS five years ago has been advanced by the 2014 rules, which were originally framed in the summer of 2011. Fuel will be rationed more strictly than ever before and a far greater emphasis is being placed on energy recovery. Further efficiency gains will also be produced due to chassis changes cutting both downforce and drag.

Yet the changes are not as fundamental as they might have been and, as is usually the case in F1, the result is very much a compromise. Haggling has persisted throughout the gestation period, with the engine specification changed (a four-cylinder unit was initially suggested) and cost considerations putting the implementation back a year. In terms of aero at least, what we're now seeing is very similar to what we've already had.

The debate about what we're now hearing has been more pronounced - with Bernie Ecclestone among those suggesting that the roar of the departed V8s has been castrated, with slower lap times also having an adverse effect on 'The Show'. Then there's the issue of cost: a lot of teams are finding the going tough enough as it is; change doesn't come cheap.

Such a departure raises other questions too, which Martin discusses in Part Two of our feature while McLaren Technical Director Tim Goss outlines how the changes will affect chassis design.

2014 - The facts

Engine

The normally aspirated 2.4-litre V8 engines used from 2006 until last season have been replaced by 1.6-litre V6s with a single turbocharger and rev. limit reduced from 18,000 rpm to 15,000 rpm. The original intention was for four-cylinder turbo engines limited to 12,000rpm but that plan wilted in the face of opposition, notably from Ferrari.

Fuel

Fuel is injected directly into each cylinder and mass flow is controlled according to a formula which does not allow the rate to exceed 100kg/hour. Furthermore, the amount of fuel cars will start races with comes down from around 150kg to 100kg, meaning an effective increase in efficiency of approximately 33 per cent.

ERS

This is where the additional power will come from. Cars already use KERS, of course, and the device remains. However, heat energy will also be recovered from the exhaust turbine (which spins the turbo). The systems are known as Motor Generator Units (MGU-K and MGU-H respectively) and the cumulative effect will roughly be tenfold: whereas KERS in its previous guise gave an 80hp boost for 6.7 seconds per lap, ERS will offer 161bhp for 33 seconds - making the 'push to pass' button a thing of the past. A maximum of 4MJ of energy can be stored per lap.

Engine + ERS = Power Unit

This is the term being applied to the combination of hydrocarbons and voltage outlined above, although whether it catches on is another matter. Depending on how good a job Mercedes, Renault and Ferrari do, it is anticipated that overall power will remain in the region of 750bhp.

Something that definitely will be heard this year, however, is the actual sound of an F1 engine in the pitlane. The FIA's original intention had been for a reliance on electrical power only but this has now been put back to 2017.

Only five power units will be allowed this season (eight engines were previously permitted) and any use of an additional complete power unit will result in the driver having to start the race from the pitlane. Meanwhile, any changes of individual elements, such as turbo, MGUs or energy store, will result in a ten-place grid penalty.

They will therefore need to last at least 4,000km rather than 2,000km.

As is currently the case, there will be a 'freeze' with power units homologated by the FIA between 2014 and 2020. However, changes will be allowed for "installation, reliability and cost-saving reasons" while manufacturers will probably also be given the chance to make up any performance shortfall.

Gearboxes

Eight-speed gearboxes replace the previous seven while ratios will be fixed for the season (although they can be re-nominated in 2014 only). Gearboxes must also last for six consecutive races, an increase from the current five.

Chassis

Here, too, the changes are intended to boost efficiency, yet the FIA announced in December 2012 that "changes made to bodywork design, originally aimed at reducing downforce and drag for increased efficiency, have reverted to 2012 specification".

Ideas such as reverting back to ground effects - whereby a Venturi tunnel on the car's underbody generates downforce without the drag - were initially mooted but what has emerged carries, in truth, a large degree of compromise.

But that's not to say the changes are insignificant. The most fundamental change is at the front of the car, where a narrower front wing and lower nose will significantly alter the airflow. So, starting there and working back:

The front wing width is reduced from 1800mm to 1650mm

Tim Goss: "Probably one of the most significant changes is the front wing, the span of which has been reduced, moving the endplates in. That, in terms of the airflow across the car, is quite a major design challenge because the front-wing endplates are now sitting more directly in front of the tyres."

The nose, which has been raised for many seasons now as designers seek downforce by pushing as much air as possible underneath the car, is lowered from a height of 550mm to 185mm. Also, the 'step' seen for the last couple of seasons will be a thing of the past.

Tim Goss: "The rules stipulate that you must have a lower tip to the nose. One of the reasons for that is to try and prevent cars launching off the back of other cars - if a following car was to hit the rear tyre of a car in front then it would get kicked up in the air, but a lower nose would prevent that."

The chassis height has also been lowered.

Tim Goss: "There's a regulation on the chassis height that's dropped by 50mm. The chassis height towards the cockpit, the limits there are the same. So essentially, the chassis will have to drop down as you go forwards and then the nose tip continues to drop as well. The days of a high chassis and high nose tip are gone."

Side-impact structures have been made standard.

Tim Goss: "The crash tube that sits within the bodywork here will be a standardised tube. It's being developed by Red Bull and the idea is two-fold: one to reduce costs and, two, the current regulations mean that the tubes aren't particularly good in a lateral impact. They're very good at taking an end-on impact but in a lateral impact they're not particularly good. There's a longer, more triangulated tube that all teams will have to run and that will dictate the amount of freedom you've got in terms of shaping the forward sidepod and floor. All the teams at the moment tend to do slightly different things with their side-impact tubes."

No rear-wing main plane while the wing itself is slightly flatter

Tim Goss: "There's no rear-wing main plane allowed. The lower wing is not allowed at all, there's an exclusion zone that sits there.

"Then the rear-wing box as we call it, which is the height of the rear wing from top to bottom, has been reduced. Both of them take downforce off the rear of the car."

A central exhaust exit

Tim Goss: "The final significant change at the rear is that you have to have a central exhaust exit rather than exits at the sides of the car. So all exhaust systems will be exiting rearward of the rear-wheel centreline. The whole idea of moving the exhaust to that position is to prevent their use in creating extra downforce."

Weight

Engine capacity might be reduced but the additional ancillaries have pushed the minimum weight of the car up from 642kg to 691kg.

This is without fuel but includes driver weight and there is a feeling that it's actually still too low - hence the debate over whether heavier drivers might be penalised. However, the minimum weight increases by 10kg in 2015.

Tyres

Pirelli has long been working on a new tyre - indeed, last May's controversial test with Mercedes was in part undertaken with next year in mind.

As a consequence of the rule changes, Pirelli Motorsport Director Paul Hembery promised "very dramatic changes" given that electric motors produce more torque at lower revs, with 2014 cars capable of generating wheelspin when changing from fourth to fifth gear.

Although the new tyre has the same dimensions as the current model, the profile is different while the structure has also been changed to cope with the greater forces unleashed. In general, they're harder, and also slightly heavier.

Click here for Part 2, in which Martin Brundle discusses the 2014 rule changes.