Not a week seems to have passed this winter without the latest piece of speculation regarding the progress of Honda's 2016 Formula 1 efforts.

One day there is talk that the Japanese manufacturer has not made the step forward it had hoped for with updates, while the next there is a report that it has found 223hp on the dyno. Then there is talk of more reliability dramas.

What is real and what is wild speculation is hard to be certain of right now - for the truth will of course only be revealed during pre-season tests and the opening races of 2016 when Honda goes up against its rivals.

But one thing is certain: Honda learned big lessons in 2015 on its return to F1 and, as Motorsport.com finds out, changes to specific elements of the power unit have left it optimistic that progress will be coming.

Wake-up call

Honda's return to F1 so far can be divided in to three distinct phases – trouble-shooting, understanding (and more crucially accepting) what went wrong, and then improvement.

Honda's F1 boss Yasuhisa Arai himself describes the difficult early days – from that first track running at Abu Dhabi testing in 2014 until last year's Spanish Grand Prix as almost like a 'pop up game' of finding new problems and dealing with them.

"It was a new design and the hybrid system is so complicated that initially we didn't have enough experience about how to wake up the control unit," Arai told Motorsport.com last year about that troubled first running.

The early stages of 2015 were not much better, either – as Arai and his Honda engineers were constantly chasing new sensor problems.

And those issues ultimately added to Honda's woes: because it delayed the Japanese manufacturer getting a proper understanding of where it was in the performance stakes.

"I had confidence that after we fixed the electrical trouble, we would get good progress," added Arai. "But there were so many hardware problems – especially MGU-K, MGU-H, and ERS trouble.

"It looked like a disaster – a pop-up game – and when we went to Australia we hadn't prepared enough. That was my feeling at the start of the season."

Spanish breakthrough

The ongoing sensor issues which limited running, and the wound-down state the power unit could be run in, overshadowed the start of the campaign.

But by the beginning of the European season at the Spanish Grand Prix, things were much improved – and many of the sensor issues solved.

Arai continued: "Spain was a big progress for us we feel. We still had some small trouble with sensors, but maybe every team had this trouble.

"However, before Spain and after Spain was different. It stopped being the big issue."

ICE

Until the sensor issues were banished, there was no chance of Honda getting to work in properly evaluating the performance weaknesses of its design.

On its internal combustion engine, there was steady progress in improving its performance. And, although there was never a belief that it had become a match for Mercedes or Ferrari, nevertheless it was not as far off as some critics claimed.

"We did not completely catch up," admitted Arai. "But we could see where we were – and we were within touch."

And of course sorting out those sensor issues, and allowing the engine to be turned up a bit, meant other areas were suddenly exposed to greater punishment – which is why reliability remained a problem.

"There were some parts quality issues, which we changed during the season, and the sensors were updated," said Arai.

"In some areas there was a control quality issue and another was increasing the ICE horsepower – because reliability was a bit weak.

"At the start of the season horsepower was not so much, so there were not reliability issues. But when the horsepower was increasing, some areas were broken because they were a little bit weak. We were always playing catch-up."

Finding the big weakness

While the frustrations continued on track, the biggest task was in simply getting to the bottom of where the Honda power unit was lacking.

And it took until after the summer break – when the power tracks in Belgium and Italy exposed the ERS-deficiencies that often left Jenson Button and Fernando Alonso 240bhp down on rivals at the end of straight – that the reality hit home

"When did we realise? In the summer European season," admitted Arai.

"The circuits were so tough and of course the ICE horsepower was increasing, but the cars needed more high speed in a straight-line and they needed deployment as much as possible. So we were very weak on tough circuits like Monza and Spa.

"We realised at that time – which was good news. But it was also bad news because we could not change the hardware [due to the regulations]."

Compressor too small

Honda's chief weakness was singled out as the lack of recovery through the MGU-H – which is the energy recovery unit connected to the turbocharger of the engine that converts heat energy from exhaust gases in to electrical energy.

In simple terms, the Honda was not recovering as much energy as it needed. And the cause of this was traced back to the fact that its aggressive 'size zero' concept had resulted in a turbine and compressor that were too small.

"We had had to make the effort to design it inside the V-angle, but it was a little bit too small," confessed Arai.

"So we have changed the compressor and turbine for 2016. They will be a little bit bigger – but will still be inside the V-bank – with almost the same packaging."

Sub zero

It is clear from what Arai is saying that, while the turbine and compressor are changing, the 'size zero' concept remains.

"We believe in it," he said. "We have confidence that the small package is much better for the aerodynamic and chassis package.

"When you see all the other power units – the Mercedes, the Ferrari and the Renault – you can compare the sizes and see how big or how compact they are. In terms of compactness, we are maybe number one.

"We have a tiny package and we want to keep that. It is our philosophy – we want to go sub-zero!"

But would Honda not have been better off having a more conservative design for its first year back – and then pushing things more in the longer term? Arai is not convinced.

"In the early stages of development, so 2013/2014, we discussed about that – whether to go into conservative direction, or be more challenging.

"Finally we decided we should go for more of a big challenge, because if we chose the conservative layout, I think that there would no improvement and no big step up, and also no gain for the chassis side. We decided – both of us, McLaren and Honda."

Time out

Arai believes that size zero was not the real problem for Honda. He thinks the company partly paid a price last year for having been out of F1 for so long – with its engineering staff not fully up to speed with how technology in the sport had moved on since 2008.

"We left F1 in 2008, and now I feel that the lost time was very damaging for our experience, because F1 itself has dramatically improved every year," he said.

"We sat on the outside watching – of course carefully watching – but we didn't know what was happening inside F1, with the power unit changes.

"We didn't know and that gap had a very big impact for us. For 2015, many things had changed.

"It was a very steep upgrade for us, but now we have understood how to do it, what to do and when to do things."

Looking to 2016

Of course until all the new cars hit the track it is going to be nearly impossible for Honda to realise just how much progress up the grid can be expected for 2016 from the changes being planned.

But by the end of last year, you could sense some optimism from senior McLaren management and drivers Jenson Button and Fernando Alonso that Honda knew what had gone wrong – and what needed to be done to fix it.

"We have already explained to both great drivers our current situation, where our targets and our processes are," said Arai. "On everything – they trust us.

"Our weak point is already found out. The most important thing is deployment, so if the deployment is the same as the other competitors then that will be good for competitiveness.

"Sometimes it has been very hard, with very strong pain, but we knew what was the right way and the right direction."

Positive thoughts

Now, amid some optimism, the key will be in managing expectations. This time around though, Honda will be much more in tune of the challenge that lays ahead.

It is also clear that having stood up and accepted its weaknesses, it should be better able to make progress – and avoid afternoons like the Saturday at Monza where Arai was giving a particularly hard grilling by the media about why the team had not lived up to its promises.

Arai says there was justifiable reason as to why he kept talking things up last year though – and why there should be no grounds for any repeat bashing in public in 2016.

"As a team if the team management talked negative all the time or tried to play down everything then that brings the whole team down, because they look to us," he said.

"My philosophy is I shouldn't be doing that. I believe the team, they are doing their best – so they will try to do their best.

"At the real beginnings of 2014 in Abu Dhabi, with electrical problems at the very beginning, I believed if we got rid of the electrical issues then it would possibly turn out for the better.

"But, as I said, over the summer was when everything was clear – that it was a hardware issue that we had the difficulty with. Then we could put our heads down.

"At the same time it was a very difficult Saturday at Monza! But it was a good experience…"

Now it's time for Honda to put that experience to the test and show F1 what it is really capable of.