Sergio Perez, Red Bull, Bahrain International Circuit, 2021

How Honda achieved a win-win with its smaller and more powerful new F1 engine

2021 F1 season

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Changes to the technical regulations during the winter are one part of the reason why Red Bull replaced Mercedes as the team to beat on outright speed at the opening round of the 2021 F1 season.

But as Mercedes team principal Toto Wolff admitted, there has been a shift in the balance of power between F1’s engine manufacturers as well. “We’re losing a little bit on the engine side,” he conceded after qualifying in Bahrain. “Honda has done a great job.”

At the launch of AlphaTauri’s AT02, the first Honda-powered car to break cover this year, technical director Toyoharu Tanabe hinted at the gains they had made over the winter through revisions to their engine, turbine and energy recovery system. Further details of those changes were revealed in a programme aired by Japan’s government-owned broadcaster NHK, which was granted access to Honda’s F1 engine development facility at Sakura.

When the pandemic struck last year, Honda initially opted to delay its next new power unit design to 2022. But the brand’s subsequent decision to call time on its latest spell in F1 at the end of this year led the team to re-commit to a 2021 deadline for its latest V6 hybrid turbo.

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Reliability was a significant weakness for Honda when it returned to F1 with McLaren six years ago. It has made great gains since then, and last year Honda was the only manufacturer whose drivers completed the season without exceeding their allocated number of power unit elements (they did begin fitting a new power unit to Pierre Gasly’s car in Turkey, but abandoned the change, which did not stop him incurring a penalty).

With the number of races on the 2021 F1 calendar increasing to a record-breaking 23, Honda targeted further durability improvements both to see out the season and provide the opportunity for performance gains.

To do this, it developed a new coating for the engine’s cylinder heads to improve their resistance to the high temperatures and friction generated during combustion. This innovation, which has made the cylinders up to 10 times more resistant than those used in Honda’s high-revving motorcycle engines, was evaluated at the end of the year at Yas Marina.

Once validated, the more robust cylinders allowed the team to seek greater performance from its engine. This was done by reshaping the combustion chamber to increase compression, by reducing the angle at which the valves are positioned. This proved to be a win-win development: the camshafts were moved closer together, producing a more compact engine, which is easier to package within an F1 chassis.

These gains came with a downside, however. As the unit performed more efficiently, less energy was lost through the exhaust system, which deprived the MGU-H of power. To solve this, the blades of the turbine were reshaped, enabling it to perform more effectively despite the reduced exhaust energy.

Further reductions in the size of the engine, and lowering of its centre of gravity, were obtained by introducing new construction materials. These allowed Honda to reduce the engine’s bore pitch (the gap between the centres of adjacent cylinders).

Pierre Gasly, AlphaTauri, Bahrain International Circuit, 2021
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Honda’s more powerful, compact and lighter RA621H power unit therefore ticks a lot of boxes for Red Bull and AlphaTauri. Its capabilities were demonstrated with pole position for Max Verstappen and fifth on the grid for Gasly’s AlphaTauri.

Neither quite hit the same heights in the race – Verstappen lost out to Lewis Hamilton’s Mercedes and Gasly’s evening was compromised by damage. But the drivers were quick to praise the latest developments from Sakura – Verstappen said Honda’s engineers had “a great winter”.

There may yet be some concerns over reliability, however. Troubling signs in the data from Sergio Perez’s RB16B and Gasly’s AT02 in Bahrain led to new electronics and batteries being fitted to both. Whether Honda’s gains have come at the expense of its 2020 reliability record remains to be seen.

Thanks to Daniel Bialy for his contribution to this article.

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31 comments on “How Honda achieved a win-win with its smaller and more powerful new F1 engine”

  1. I do not like the sound of having to fit a new Control Electronics after just 3 sessions in the season. Especially, that the cars are only allowed to carry 2 of those in a single season.

    1. I believe that is a standardised bought-in part which is not part of the PU produced by Honda.
      @krichelle

      Having said that, I’m not sure why they limit the replacement of that part.
      It doesn’t seem to be a part which gets worse when being used, nor can the teams design more robust versions which will last longer.

      1. @coldfly The control electronics (CE) that were replaced are actually distinct from the ECU, which is the standardized part. The CE (per F1 Technical Regulations) “includes, but is not limited to, MGU-K control unit, MGU-H control unit, injector control unit, ignition control unit, DC-DC. It excludes and FIA Standard ECU, FIA sensors, and ES safety controls”

        1. Thanks, @g-funk.
          That of course makes it 100% Honda’s responsibility.

          1. Which then begs the question, can they fix the ES and CE they replaced in SP’s car, and thus retain their standing with two good units of each, or have they now burned through one set and have to go the rest of the season on the one of each or otherwise incur a grid penalty if they have to again at some point install one or both that would be termed their third ones?

          2. I don’t understand how they can brag about reliability after perez’s problem, it seems like it’s always been, not very reliable.

          3. @esploratore Where are ‘they’ bragging about reliability? And how does Perez issue erase the reliability they had last year and could well continue to have for the most part this season?

          4. @robbie in the Technical Regulations, it states that, as soon as the car has left the pit lane with that component on board, it becomes part of the component pool that the teams must use and the specification of those components is then fixed at that point in time.

            There are a few ancillary components which possibly fall outside of that restriction – mainly a few minor cooling components – but any other physical alteration would void the homologation and render it ineligible for re-use. I would suspect that the most that they might be able to do is to make minor adjustments to any associated software, but even that will likely be rather limited.

            If they can’t be re-used in race trim, then the better case scenario may be if they can at least salvage those components for practice sessions only – it will still present problems and may necessitate an extra set of components later in the season, but that could help them defer it for as long as possible. If they’re a complete write off, then it’ll be a case of making strategic plans for stretching the remaining allocations as late into the season, before picking a race where it’s not so difficult to overtake to make a change and take a tactical grid penalty.

          5. Okay good stuff anon, thank you.

          6. Back when Red Bull was running Renault PUs, there was just a bit of angst on their part that they were having to swap parts between PUs in order to keep things running. Seems that there was a shortage of spares along the way.
            Unless the regs have changed, it would appeared, that it was permissible to reuse previously removed parts. Assuming that no modification or breaking of any seals is undertaken. Since much of the CE function is likely to be software related, it would be expected that this can be re-booted at some point.
            Can only imagine that Honda is doing all they can to recover the CE unit and return it to service.
            We should find out if they are successful in about 10 races or so.

          7. @rekibsn whilst that might be possible with the Control Electronics, that wasn’t the only component that had to be replaced. As noted in the article, the Energy Store also had to be replaced on both Perez’s and Gasly’s cars, as they also had problems with that – and that is something that they might not be able to solve quite as easily.

  2. sounds GREAT !
    thx for the insight !
    so EAGERLY looking forward to the outcome

  3. Stating the obvious, but wow Honda have come a long way since 2015. Shame that they’re pulling out of the sport again, and at a time when it seems they are on track to become the best PU.

    1. Honda being who they are, it really was just a matter of time, before they would get there…yet it took much longer than anyone expected. And now they are leaving…

      1. Actually it didn’t take them that long imo, considering how complicated engines are.

      2. …And having taken a decision to leave, they can’t now reverse it even if that is seen to be the better option.
        Yes it took five years longer than expected to come up with a winning engine, but then the average age is very advanced. Most of the Honda F1 personnel are veterans of the Russo-Japanese War of 1905.

        1. Just to let zou know that at least one reader appreciated the joke

  4. Re control units:
    When it comes to electronics, automotive electronics included, the first 6 months will see the most failures
    due in general to some part being of borderline quality.

    Once this/these part/s fail the unit will not perform as intended and may fail completely. Nothing to do with the design
    but with the parts that passed inspection but had inherent weaknesses

  5. Marks my words…

    At the end of the season 100% we will see a clear Mercedes champion again. Possibly a good bit before the end if the season. Red Bull are flattered by the rule changes and although Honda might have made a step forward, it’s still not significant compared to Mercedes. Once Mercedes sort out their aero it’s game over I’m afraid. Not a Ham or Merc fan really but this is the reality. Screenshot this and call me out soon.

    1. Anon you certainly have 7 years worth of seasons to go by, not to mention pretty much everyone’s assumption that you are right, even after race 1, or lol perhaps especially after. As stoked as I am for Max about RBR’s new found form, I am not willing to take that to the point of an assumption about what that means for their chances at the season’s end. They run all the races for a reason, and we’ll just have to see, and I think if Max/RBR prevail that will be much more the surprise than if Mercedes do. If I would debate you on anything it is that it might not be ‘a good bit before the end of the season’ but rather close to the end. It is a plain and simple fact that for 8 seasons now it is up to another team to knock Mercedes off the block, and that takes a full season for them to prove they can, or at least hopefully a good majority of it lol.

      1. @robbie It’s certainly heartening to see that the Honda PU appears to be, at the very least competitive, but my take is that for the first time in a long while RBR seem to have brought a much better chassis and aero package that performed from the start of the season.
        If anything Mercedes seem to have “done a RBR” this year and brought a good chassis that needs fine tuning to unlock performance. To me it’s how quickly they unlock it that could well determine the outcome of this season – if they manage it within the first 3 races, I believe that we’ll see a battle royale down to the wire. If they take half the season, as RBR has in the past few seasons, I’d expect that RBR should run away with the title(s) fairly easily much like Mercedes has done for the past few.

        Here’s hoping we see some epic battles where the WDC is on the line this year rather than spending the season waiting for one team to sort out its chassis before the battles can truly commence by which time one driver is so far in front he can afford to not battle all that hard.

        1. Hear-hear, and if you know that Mercedes also had a new spec they made up a lot of power. Just lets hope it get more racey that is al what the real fans want (as Max fan can enjoy Lewis became champion if the rest of the 22 races are as the first)

          1. and if you know that Mercedes also had a new spec

            to what end.?. they can not use it this year.

    2. Anon Yep

    3. the real disadvantage of the mercs is not shown yet.
      Red bull did turn the engine down and the dif caused more loss of time.
      Merc stopped the development last year early to go all in the new 2021 car. For now its quite a disappointment.
      The real pain for Merc will come soon.

  6. Super interesting article. Last year honda effectively opted out of f1 after realising their great winter was in fact a megre one compared to merc’s. Honda publicly questioned mercedes shortly before throwing the white flag. In the end regardless of the veracity or provenance of this intel I cannot believe that these changes indeed turned Honda into the best PU in the game. Looking at quali, looking at the sectors, watching the race, all points out similar to last season, that mercedes is a good step ahead of everyone else.

    1. @peartree remind me again what Honda doubted about Mercedes, I’ve forgotten it

      1. @balue Honda was buoyed by their pre-season but when the season started they said they couldn’t explain or understand how merc had made such a big step. Binotto then said they saw suspicious performance from the merc engine on cornering.

        1. @peartree right, yeah that was weird

  7. i dont expected to be better, but it seems honda have the best package than last year.they hiding something. but obviously not.let see who will give the best output for 2021. my favorite is always RBR and Merc,will they bot gonna give us the best race enternaing like ferrari and mclaren?

  8. I wonder how long it will be before Renault comes knocking on RedBull’s door to license the Honda engine?

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