The story behind F1's latest engine debate

Will the questions over whether F1 engine customers have access to the same performance levels as works team finally go away in 2018? That is certainly the FIA's intent, and its push for parity for customer teams can only be good for the championship.

But who was lobbying for this new focus on parity? And which of the six customer teams - in other words everyone except Mercedes, Ferrari, Renault and sole Honda partner Toro Rosso - stands to gain?

On January 28, F1 teams were surprised by the arrival of FIA technical directive TD/005-18. Such documents are often routine regulation housekeeping, but this one captured everyone's attention, as it had not been expected.

Under the current hybrid regulations the FIA has always ensured that customer teams receive the same homologated hardware as works cars, unless they have voluntarily agreed to stick with the previous year's specification for cost reasons. If a manufacturer produces an upgrade for its works cars, it is obliged to provide it to customers at the first opportunity.

Hardware is relatively easy to monitor, but software is a little more complex. Since the current rules came in there have been suspicions that some works teams may have access to extra power modes, for example in Q3, that others don't have. And it's those concerns the FIA has addressed with its recent directive.

In it, F1 race director Charlie Whiting pointed out that while the aim of the rules was to "ensure that all power units supplied by one manufacturer are identical in all respects, we have good reason to believe that this may not be the case".

"Whilst the dossiers for each team may be identical it would appear that some are being operated in a different way to others being supplied by the same manufacturer," the directive continued.

"It is therefore our view that all power units supplied by one manufacturer should be identical, not only in terms of the dossier for each team being the same, but we also feel they should be operated in an identical way."

Whiting concluded that power units must from now on be "run with identical software and must be capable of being operated in precisely the same way" and "run with identical specifications of oil and fuel".

A rider to the latter requirement is that teams can still opt out and run with a different fuel supplier than the works cars. In fact, the only team to do its own thing in 2018 is Red Bull, which has a deal to use ExxonMobil instead of BP/Castrol, as favoured by Renault.

The FIA has long homologated fuel "footprints", and by happy coincidence in 2018 it is also inspecting and checking oil for the first time, as part of its policing of the new oil burn rules. It will therefore be able to ensure that Williams and Force India have the same Petronas products as Mercedes, Haas and Sauber the same Shell supplies as Ferrari, and that McLaren - prior to switching to Petrobras in 2019 - has identical BP/Castrol specs to Renault.

No manufacturer is ever going to admit that it has not always provided equal performance potential to its paying customers and, similarly, we rarely hear those customers - tied in to long-term deals with contracts that discourage them from saying anything too controversial - suggest they are not getting a fair service.

However, one man did voice his concerns back in 2014, towards the end of a curious season when McLaren ran with Mercedes power while helping Honda to prepare for its debut. At Suzuka, Ron Dennis had a little moment of "engine rage" and made his feelings clear.

"One thing that jumps you if you look at all of the qualifications of all of this year is the time difference between the Mercedes-Benz works team and the other teams," he rued. "By and large it's always in excess of a second, putting aside the pace which they can generate in a grand prix when they're on the back foot.

"A modern grand prix engine in this moment in time is not just about sheer power, it's about how you harvest the energy, it's about how you store the energy, and effectively if you don't have control of that process - meaning access to source code - then you are not going to be able to stabilise your car in the entry to corners, etc, and you lose lots of lap time. So even though you have the same brand of engine that does not mean you have the ability to optimise the engine."

The "source code" terminology was a little archaic and, considering the Honda links, no one could blame Mercedes for being a little cautious with McLaren that year. Most significantly, the Woking team eventually acknowledged that the ExxonMobil fuel it had chosen wasn't quite as effective as the Petronas in the works cars.

"It's not relevant for us, because the rules state you must supply customers the same hardware and software, and we've always done that. That's why we have no problem with that" Mercedes boss Toto Wolff

But Dennis made a valid point, and given no current team boss is likely to express similar trenchant views, it's as good an encapsulation of the fears that the FIA is currently addressing as we are likely to get. Dennis is long gone, and McLaren is just starting its new relationship with Renault, so is hardly in a position to stir the pot with the FIA just yet. So which team did lobby the FIA on parity?

More than one paddock source, including Red Bull boss Christian Horner, pointed at Williams as the possible inspiration for the clampdown. And the theory makes some sense. After all, the Grove team's technical boss Paddy Lowe is probably the only person outside the current inner sanctum of the works Mercedes team - other than Nico Rosberg - who knows exactly how it operates its power units.

Then consider Lawrence Stroll, a man who is bringing substantial funding to Williams, and who is not known for holding back when it comes to voicing an opinion. The Canadian is obviously keen to ensure that no stone is left unturned in creating a competitive package for son Lance. If there was a debate over power unit parity within the Williams camp, surely Lowe would address Stroll Sr's concerns by encouraging the FIA to put a special focus on the subject?

It's a credible theory, but Lowe himself denies that Williams lobbied the governing body.

"I heard that rumour!" he told Autosport at Barcelona last week. "But if you analyse it, it's probably bad for us, because I'm not aware of any difference that memo will make to Mercedes.

"It might affect other engine manufacturers, in which case it will bump up some of our potential rivals, like McLaren or Red Bull, for the sake of argument. On that basis it certainly would not be in our interest to have promoted it.

"But it was something that in my view was inevitable. For a long time they've said that the engines should be the same. They did it to the hardware, and for some reason they didn't enforce it across the software. But that's quite a significant component..."

Lowe made the obvious point that a manufacturer wants everyone to have the same equipment and operate it to the same limits, because that way it gets more useful feedback.

Mercedes F1 boss Toto Wolff, who was unimpressed by Dennis's 2014 outburst, is still adamant that his company has always played fair with its teams. "I don't think any of our customers was pushing for it," he said. "It's not relevant for us, because the rules have been in place for a while that you must supply the customers with the same hardware and software from a power unit standpoint, and we've always done that.

"That's why we have no problem with that. If there is any suspicion out there, it certainly wasn't anything that would have any consequence for us. We have the belief that sharing modes and engine calibration among six cars triggers a steeping learning curve for us than running different engine specifications between the customers and the works team."

Wolff says that the customers do have use of the same magic qualifying modes as the works cars - but the public might not notice, because they are typically used at the end of Q2 to get through to Q3. He also downplays any suggestion that those teams may have theoretical access to special modes, but don't or can't use them for reliability reasons - "would we run a mode that would risk our engine life?" - and remains adamant that his customers have not been lobbying the FIA.

"I don't think it was Williams," says Wolff. "Think about it. What reason would we have to not give Williams or Force India the maximum performance? We have every reason to give it to our customer teams, because we want them in the ballpark, we want them to take points away from the competitors.

Renault has a reputation for being fair to its customers, and there have been times when the French marque wasn't present in its own right. That changed when it returned as a works team, but it was never going to be near Red Bull on the grid

"It must have come from somebody who thought he might be screwed over by a works team, and there are some guys out there who have paranoia all the time..."

You don't have to be a rocket scientist to work out he was referring to Horner. The Red Bull boss has frequently complained about Renault reliability and performance, but refutes suggestions the French manufacturer has failed to provide his team with the same technology as the works cars.

"We've never doubted we have had parity with Renault," Horner said at Barcelona last week. "We have a different fuel and oil supplier. We haven't seen anything concerning about the product we have been supplied by Renault.

"Renault have always been very fair with what they have supplied, whether they have had their own teams or just been as an engine supplier. That continues."

Renault has a good reputation for being fair to its customers, and, as Horner reminds us, there have been times when the French marque wasn't present in its own right, so it was a moot point anyway. That changed with the return of a works team in 2016, but given it was in the early days of the rebuilding process, Enstone was never going to be near Red Bull on the grid.

The intriguing thing is that in its third year it has to be towards the sharp end, potentially fighting not just Red Bull but new customer McLaren. In other words, it would arguably now be more tempting than it has been for many years for Renault to save a little something extra for itself - had the rules not been tightened by the FIA.

"I know it's a constant concern from customer teams and for very good reason, to make sure they are treated equally," says Renault Sport boss Cyril Abiteboul. "Because that certainly should be the case. It's the way we've been acting towards our customers in our 40 years of being an engine supplier in F1. That's was always our intent, that's always been in the regulations, now there is a clear directive in relation to that.

"But we also have to accept that there will always be some differences. Just to give you one example, and I don't want to create a debate in relation to that, but for instance Red Bull is using a different petroleum partner.

"So they will be using a different type of fuel and lube, and that's creating some small differences, but they know that, and they've done their decisions. Our partner was available for them, but they preferred to use a different partner."

The third customer engine supplier is Ferrari, and given how close it is commercially to Haas and now Sauber, it's hard to imagine there's much motivation for Maranello to actively handicap either in any way. As Wolff suggested regarding Mercedes, manufacturers want customers up there scoring points, and there's every reason for Ferrari to want its junior Charles Leclerc to shine in his rookie year.

That said, when I joked with Sauber boss Frederic Vasseur about the FIA now obliging Ferrari to keep the Swiss fully team up to date with software upgrades and new Shell fuel/oil specs - possibly to an extent that Sergio Marchionne hadn't anticipated when he agreed the Alfa deal a few months ago - he allowed himself a smile...

The point is that if a manufacturer doesn't want to give its best power units to a team it sees as a threat, it simply doesn't do business with them. That's the real strategic decision for the company, not the option of keeping the best qualifying modes for its own cars.

Only a couple of years ago Red Bull's attempts to hook up with Mercedes or Ferrari were blocked by both manufacturers. Understandably, neither was keen to hand its engines over to a team that had the potential to build a better chassis package than their own. With no other choice, Red Bull remained aligned with Renault in a marriage of inconvenience.

For 2019 it has the option to switch to Honda and share works status with sister team Toro Rosso - and, if that happens, Red Bull can have no doubts about getting the best its supplier has to offer.