Honda Power Unit Hardware & Software

[bigblue]

Here's a thought. This is all beginning to get just a little bit personal, some, uh, reasonably robust views expressed, sometimes in slightly abrasive manner. We all know the characteristic viewpoints that are held, and everyone's had a go at expressing their scepticism on certain opinions. So, before this really ignites, let's just concentrate on the actual performance and see what happens.

My cowardly guess is 30hp plus or minus 10, but that basically covers all realistic scenarios, if you believe Orihara's significant-ish-but-you'll-be-disappointed-if-you're-expecting-50bhp. There's quite some work to do on reliability too as they're munching through PU allocations, but I suppose that's of secondary importance right now (not sure if some solutions will arrive with the new spec).

[ispano6]

(I've been on a "vacation" so this is a tad belated.)

Wow. Saying "I have no bias other than to point out your guys bias" has to be some of the most biased things anyone can ever write.

Not only that, your bias is incredibly huge and obvious. You're quick to throw anyone and anything under the bus to shift away blame from Honda. Whether it has and basis or sense does not seem to matter
Whether it's Newey designing a "bendy chassis", or it's "all the suspension's fault', or it's "the gearbox", or lately the "Honda is lacking in power because of Aramco", or just accusing Newey of lying.

You said you provided sources to the AI, but you provided none here for the purported fuel issue. You just insulted people, by telling them to ask the AI.

Everyone should take with a good amount of doubt what you claim when it concerns Honda or anything related to Japan. As long as you don't provide a hard source.

People here are too lazy to find the sources themselves and read it from the HRC F1 website. I aint doing other people's homework. Long time members can vouch that I've said nothing wrong. I never say lies or bullshit. It's against my grain. I call it out when I see it. Folks like you make me want to not contribute.

Also, some sources aren't published articles for people to mistranslate. It's only on F1 shows on Japanese television. I would record the show and share it here but I've already decided people here don't deserve that. A lot of people then misinterpret the CC captions and run with ignorant comments thereafter. Just watch and appreciate Honda.

I agree with mzso. You're just FFull on BS.

The funniest BS story is the one where AMR begged Honda to come back.

February 3, 2023 – Honda registered with the FIA as a 2026 power unit manufacturer.
May 24, 2023 – Honda and Aston Martin officially announced their exclusive works partnership and Honda's full return to F1. Honda was involved in the discussions that shaped the 2026 regulations before it formally registered as a power unit manufacturer in February 2023. So it knew it was coming back in, just didn't formerly announce it till February.

You can try to discredit me all you like but you did not include the one fact that I HAD CALLED OUT SPECIFICALLY.
WHAT YEAR DID HONDA DISBAND THEIR DREAMTEAM? 2021. I rest my case.

They registering wasn't just to be available for some team to pick them up. They were in discussion with AMR.

[ispano6]

@diffuser
You also incorrectly claimed Aramco's F2 and F3 experience would give them an advantage and best fuel of F1.

Here's the article from JP motorsport from Jan 7 2025 where Aramco's representatives specificaly stated their F2 and F3 involvement had NO advantage.

https://jp.motorsport.com/f1/news/f2-f3 ... /10686891/

Pierre-Oliver Carendini, Director of Aramco's Fuel Research Center:

As mentioned earlier, the fuel used in F2 and F3 is bio-derived. However, in the future, synthetic fuels will be produced using carbon dioxide captured from the air and hydrogen produced by electrolyzing water...... They aim to achieve so-called e-fuel. From 2026, it is highly likely that the fuel used in Aston Martin F1 will be this e-fuel.

"F1 and F2 use different fuels and regulations. After all, the engines aren't the same."

That's what Calendini says.

"Even if some components are the same, the fields we compete on are different."

"Depending on the engine regulations, the fuel itself can vary quite a bit. Motorsports...... Especially in F1, it's necessary to adjust the fuel composition to maximize power. Other competitors...... Shell, Petronas, and ExxonMobil are pushing their limits to deliver top performance.

"On the other hand, F2 and F3 use the same engine and the same fuel. You can balance performance."

However, in the fundamental aspect of producing sustainable fuel, it may be an advantage...... When asked this, Calendini explained:

"To be honest, that's not true. On the contrary, you could say that everything we do with our partners has helped us gain knowledge."

[ispano6]

Redesigned combustion chamber. New combustion chamber geometry to improve thermal efficiency.
Source: Shintaro Orihara –
The Race – 2 July 2026.
Revised pre-chamber. Modified pre-chamber design to improve flame propagation and combustion stability.
Source: Shintaro Orihara –
The Race – 2 July 2026.
Reduced internal friction. Honda confirmed work on reducing internal mechanical friction to improve ICE efficiency.
Source: Shintaro Orihara –
The Race – 2 July 2026.
Improved combustion characteristics. The new specification changes the engine's combustion characteristics and requires revised engine calibration.
Source: Shintaro Orihara –
RNT Motorsports – 2 July 2026.
Drivability optimisation. New engine maps have been developed to optimize drivability around the revised combustion process. Source: Shintaro Orihara –
RNT Motorsports – 2 July 2026.
Internal Power Unit update. All modifications are internal to the power unit. No chassis or installation changes are required.
Source: Shintaro Orihara –
The Race – 2 July 2026.
Performance-focused package. Honda describes the upgrade as a "reasonably big step", but not a miracle solution. The objective is to close the gap to the leading manufacturers through higher combustion efficiency and lower mechanical losses. Source: Shintaro Orihara –
The Race / RNT Motorsports – 2 July 2026.
This is all i could find about the upgrades for zandvoort. latest obviously

To add,
as-web.jp July 7

——何が変わるのですか？

折原GM：「燃焼にまつわる部分に手を加えました。たとえば、プレチャンバー（副室）あたりは変えました（スパークプラグの先に副室を設け、副室で着火した火炎が主室との間にある壁にある小さな孔から主室側に勢いよく噴き出し、主室の混合気を一気に燃焼させるシステム）。また、ピストンの形状も変えましたし、燃焼室の形も大きく変わります」

——燃焼室やピストンの形状を変えるのはかなり大きな変更ですね。

折原GM：「パフォーマンスを上げるために、ピストンの形状を変えるのは一般的です。 ただ、ピストンの形状を変えれば、信頼性の確認が大きな課題になります。信頼性をクリアするためには、やはりオランダGPまで時間を要するということです」

—— What will change?

GM Orihara: "We made modifications to the combustion-related areas. For example, we changed the pre-chamber (auxiliary compartment) (a system where a sub-compartment is installed at the end of the spark plug, and the flame ignited in the auxiliary chamber is forcefully sprayed toward the main chamber side through a small hole in the wall between the main chamber and the main compartment, burning the main chamber's mixture all at once). We also changed the shape of the piston, and the shape of the combustion chamber is also significantly altered.

——Changing the shape of the combustion chamber and pistons is quite a major change.

GM Orihara: "It is common to change the shape of the pistons to improve performance. However, if the piston shape is changed, verifying reliability becomes a major challenge. To clear the reliability criteria, it still takes time until the Dutch GP."

[diffuser]

@diffuser
You also incorrectly claimed Aramco's F2 and F3 experience would give them an advantage and best fuel of F1.

Here's the article from JP motorsport from Jan 7 2025 where Aramco's representatives specificaly stated their F2 and F3 involvement had NO advantage.

https://jp.motorsport.com/f1/news/f2-f3 ... /10686891/

Pierre-Oliver Carendini, Director of Aramco's Fuel Research Center:

As mentioned earlier, the fuel used in F2 and F3 is bio-derived. However, in the future, synthetic fuels will be produced using carbon dioxide captured from the air and hydrogen produced by electrolyzing water...... They aim to achieve so-called e-fuel. From 2026, it is highly likely that the fuel used in Aston Martin F1 will be this e-fuel.

"F1 and F2 use different fuels and regulations. After all, the engines aren't the same."

That's what Calendini says.

"Even if some components are the same, the fields we compete on are different."

"Depending on the engine regulations, the fuel itself can vary quite a bit. Motorsports...... Especially in F1, it's necessary to adjust the fuel composition to maximize power. Other competitors...... Shell, Petronas, and ExxonMobil are pushing their limits to deliver top performance.

"On the other hand, F2 and F3 use the same engine and the same fuel. You can balance performance."

However, in the fundamental aspect of producing sustainable fuel, it may be an advantage...... When asked this, Calendini explained:

"To be honest, that's not true. On the contrary, you could say that everything we do with our partners has helped us gain knowledge."

"Conversely, we can say that we gain knowledge through everything we do with our partners."

I never said they were the best. I just said they were working on the new fuel. They didn't dismantle their team in 2021 like Honda did. They kept working on the fuel.

Because Honda no longer had many of its key people, it didn't end up doing much on the combustion side. Yet you're 100% convinced that Honda's ICE power problem was entirely the fault of the fuel. I'm very skeptical of that. Based on what we've seen this year, along with the dismantling of the team in 2021, I think it's far more likely that the problem stemmed from a weakness on Honda's side.

You also keep bringing up this synergy with Exxon, but both the fuel and the ICE combustion regulations changed dramatically. They had to throw out everything they had done before and start over. Hell, even Honda moved its engineers to other projects. So this "Exxon synergy" would have been with whom exactly? And based on what? The requirements of the old ICE, whose technology couldn't be reused for the 2026 engine?

I'm not saying the fuel isn't a problem but there is a big red arrow pointing at Honda for resource issues they had for the years coming into 2026 that is very hard to ignore. In fact the resource issue continued into the first quarter of 2026.

[ispano6]

moved

[ispano6]

I never said they were the best. I just said they were working on the new fuel. They didn't dismantle their team in 2021 like Honda did. They kept working on the fuel.

Because Honda no longer had many of its key people, it didn't end up doing much on the combustion side. Yet you're 100% convinced that Honda's ICE power problem was entirely the fault of the fuel. I'm very skeptical of that. Based on what we've seen this year, along with the dismantling of the team in 2021, I think it's far more likely that the problem stemmed from a weakness on Honda's side.

You also keep bringing up this synergy with Exxon, but both the fuel and the ICE combustion regulations changed dramatically. They had to throw out everything they had done before and start over. Hell, even Honda moved its engineers to other projects. So this "Exxon synergy" would have been with whom exactly? And based on what? The requirements of the old ICE, whose technology couldn't be reused for the 2026 engine?

I'm not saying the fuel isn't a problem but there is a big red arrow pointing at Honda for resource issues they had for the years coming into 2026 that is very hard to ignore. In fact the resource issue continued into the first quarter of 2026.

So now you've changed your stance. I won't bring up your specific posts that attempted to downplay the fuel factor.

Early concerns that were raised in F1-gate.com in January 2026 after Honda had mentioned the synergy/matching problem they were encountering. I won't quote the whole article.
https://f1-gate.com/honda/f1_91978.html

Why compatibility with Honda PUs is questioned:
Honda has always placed combustion technology at the core of its power unit development. Stable output characteristics at high RPMs is also part of Honda's engine philosophy.

When combined with fuels with high calorific value, it could potentially enhance the overall characteristics of the power unit. It affects not only the individual engine performance but also usability across the entire RPM range and how peak power is produced.

However, this is not a matter that can be achieved solely by fuel. Optimization of combustion chamber design, ignition timing, and energy management is a prerequisite, and fuel and power units need to be developed as a single unit.

The real differences that are hard to see in tests: In preseason tests held in Barcelona and Bahrain, these fuel-derived performance differences do not always become apparent. Each team strictly manages their running programs, fuel capacity, and engine modes, leaving their true potential hidden.

Still, as the season progresses, differences in high-rev range and energy efficiency become apparent in race pace, top speed, and even a wide range of strategies. Fuel is an invisible factor that definitely affects performance differences.

Overall strength tested in 2026 F1 2026 F1 will be an era where simply having a superior chassis or powerful electric systems won't be enough to win. The overall level of completion, including fuel, engine, and energy management, determines the final competitiveness.

How much of a performance difference can the Aramco fuel that powers Honda PUs create at high RPMs? The answer should gradually become clear not only in the opening match but throughout the season. The hard-to-see area of fuel is the crucial key that will determine the power map of F1 in 2026.

[diffuser]

I still said the fuel is unlikely to be the problem. Remember, big arrow pointing at Honda for resources quality and shortage from 2021. No arrow pointing to Aramco for resource shortage abandoning projects etc. They kept working on the fuel.

[mzso]

Early concerns that were raised in F1-gate.com in January 2026 after Honda had mentioned the synergy/matching problem they were encountering. I won't quote the whole article.
https://f1-gate.com/honda/f1_91978.html

Why compatibility with Honda PUs is questioned:
Honda has always placed combustion technology at the core of its power unit development. Stable output characteristics at high RPMs is also part of Honda's engine philosophy.

When combined with fuels with high calorific value, it could potentially enhance the overall characteristics of the power unit. It affects not only the individual engine performance but also usability across the entire RPM range and how peak power is produced.

However, this is not a matter that can be achieved solely by fuel. Optimization of combustion chamber design, ignition timing, and energy management is a prerequisite, and fuel and power units need to be developed as a single unit.

The real differences that are hard to see in tests: In preseason tests held in Barcelona and Bahrain, these fuel-derived performance differences do not always become apparent. Each team strictly manages their running programs, fuel capacity, and engine modes, leaving their true potential hidden.

Still, as the season progresses, differences in high-rev range and energy efficiency become apparent in race pace, top speed, and even a wide range of strategies. Fuel is an invisible factor that definitely affects performance differences.

Overall strength tested in 2026 F1 2026 F1 will be an era where simply having a superior chassis or powerful electric systems won't be enough to win. The overall level of completion, including fuel, engine, and energy management, determines the final competitiveness.

How much of a performance difference can the Aramco fuel that powers Honda PUs create at high RPMs? The answer should gradually become clear not only in the opening match but throughout the season. The hard-to-see area of fuel is the crucial key that will determine the power map of F1 in 2026.

The summary of this is that "the fuel is important".
The problem is you contorted this into "Honda engine is bad because the Aramco fuel is bad". Your bias twisting the facts.
Now, if you only quoted the article it would have been interesting information about the challenges.

[mzso]

Redesigned combustion chamber. New combustion chamber geometry to improve thermal efficiency.
Source: Shintaro Orihara –
The Race – 2 July 2026.
Revised pre-chamber. Modified pre-chamber design to improve flame propagation and combustion stability.
Source: Shintaro Orihara –
The Race – 2 July 2026.
Reduced internal friction. Honda confirmed work on reducing internal mechanical friction to improve ICE efficiency.
Source: Shintaro Orihara –
The Race – 2 July 2026.
Improved combustion characteristics. The new specification changes the engine's combustion characteristics and requires revised engine calibration.
Source: Shintaro Orihara –
RNT Motorsports – 2 July 2026.
Drivability optimisation. New engine maps have been developed to optimize drivability around the revised combustion process. Source: Shintaro Orihara –
RNT Motorsports – 2 July 2026.
Internal Power Unit update. All modifications are internal to the power unit. No chassis or installation changes are required.
Source: Shintaro Orihara –
The Race – 2 July 2026.
Performance-focused package. Honda describes the upgrade as a "reasonably big step", but not a miracle solution. The objective is to close the gap to the leading manufacturers through higher combustion efficiency and lower mechanical losses. Source: Shintaro Orihara –
The Race / RNT Motorsports – 2 July 2026.
This is all i could find about the upgrades for zandvoort. latest obviously

To add,
as-web.jp July 7

——何が変わるのですか？

折原GM：「燃焼にまつわる部分に手を加えました。たとえば、プレチャンバー（副室）あたりは変えました（スパークプラグの先に副室を設け、副室で着火した火炎が主室との間にある壁にある小さな孔から主室側に勢いよく噴き出し、主室の混合気を一気に燃焼させるシステム）。また、ピストンの形状も変えましたし、燃焼室の形も大きく変わります」

——燃焼室やピストンの形状を変えるのはかなり大きな変更ですね。

折原GM：「パフォーマンスを上げるために、ピストンの形状を変えるのは一般的です。 ただ、ピストンの形状を変えれば、信頼性の確認が大きな課題になります。信頼性をクリアするためには、やはりオランダGPまで時間を要するということです」

—— What will change?

GM Orihara: "We made modifications to the combustion-related areas. For example, we changed the pre-chamber (auxiliary compartment) (a system where a sub-compartment is installed at the end of the spark plug, and the flame ignited in the auxiliary chamber is forcefully sprayed toward the main chamber side through a small hole in the wall between the main chamber and the main compartment, burning the main chamber's mixture all at once). We also changed the shape of the piston, and the shape of the combustion chamber is also significantly altered.

——Changing the shape of the combustion chamber and pistons is quite a major change.

GM Orihara: "It is common to change the shape of the pistons to improve performance. However, if the piston shape is changed, verifying reliability becomes a major challenge. To clear the reliability criteria, it still takes time until the Dutch GP."

Practically everything important for performance changes. This could go very well, or very poorly.

Too bad they don't say how they address vibrations.

[Badger]

—— What will change?

GM Orihara: "We made modifications to the combustion-related areas. For example, we changed the pre-chamber (auxiliary compartment) (a system where a sub-compartment is installed at the end of the spark plug, and the flame ignited in the auxiliary chamber is forcefully sprayed toward the main chamber side through a small hole in the wall between the main chamber and the main compartment, burning the main chamber's mixture all at once). We also changed the shape of the piston, and the shape of the combustion chamber is also significantly altered.

——Changing the shape of the combustion chamber and pistons is quite a major change.

GM Orihara: "It is common to change the shape of the pistons to improve performance. However, if the piston shape is changed, verifying reliability becomes a major challenge. To clear the reliability criteria, it still takes time until the Dutch GP."

Practically everything important for performance changes. This could go very well, or very poorly.

Too bad they don't say how they address vibrations.

These are very substantial changes to be making on such short notice. Begs the question if these changes have been worked through properly or if there's an element of rushed panic there, basically redesigning the engine for more power at the expense of reliability. They even allude to the fact that reliability verification hasn't been completed yet and we are only weeks out. I'm just not sure how much I trust this Honda working group to provide a quick fix to a problem caused by their own incompetence. How much can really change in six months on something as complex as the engine?

[Bence]

Wazari wrote to me back in January that they struggle with the Aramco fuel because its composition causes oil dilution issues. Because of that and some sensor & software glitches, the 626 was not reliable and Honda wasn't pushing the PU above roughly 75%. Further struggle was the management/flattening of sudden torque peaks Honda experienced with their unique harvest/deploy sequences which were the cause of the destroyed gearboxes. Also the PU by itself didn't vibrate at all up until 15k RPMs, but as the K was mounted directly to the survival cell, the whole package hit some (dis)harmonic resonance and it was difficult to cure.

As you may remember the totally straight and ultra smooth driveline of the first Lexus LS400, even a couple of degrees can cause havoc if frequencies are happen to disturb/amplify themselves in unwanted places. I would have examined the entire chassis-engine integration from a cymatic POV to see where those harmful vibrations start to form.

[mzso]

These are very substantial changes to be making on such short notice. Begs the question if these changes have been worked through properly or if there's an element of rushed panic there, basically redesigning the engine for more power at the expense of reliability. They even allude to the fact that reliability verification hasn't been completed yet and we are only weeks out. I'm just not sure how much I trust this Honda working group to provide a quick fix to a problem caused by their own incompetence. How much can really change in six months on something as complex as the engine?

It doesn't matter if reliability suffers, if they want to catch up they need to develop aggressively and fix flaws later.
Since they have an ADUO update they don't plan on using they can rely on that to provide a hotfix if something goes wrong. (and normal reliability updates if reliability is what actually suffers.)

[mzso]

Wazari wrote to me back in January that they struggle with the Aramco fuel because its composition causes oil dilution issues. Because of that and some sensor & software glitches, the 626 was not reliable and Honda wasn't pushing the PU above roughly 75%. Further struggle was the management/flattening of sudden torque peaks Honda experienced with their unique harvest/deploy sequences which were the cause of the destroyed gearboxes. Also the PU by itself didn't vibrate at all up until 15k RPMs, but as the K was mounted directly to the survival cell, the whole package hit some (dis)harmonic resonance and it was difficult to cure.

As you may remember the totally straight and ultra smooth driveline of the first Lexus LS400, even a couple of degrees can cause havoc if frequencies are happen to disturb/amplify themselves in unwanted places. I would have examined the entire chassis-engine integration from a cymatic POV to see where those harmful vibrations start to form.

That's weird, because publicly he said they can't go full power until the PU mounting is redesigned.

Though January was a long time ago, that might have been a transient issue.
Seeing Stroll's Monaco crash the torque problem seems to be persistent.

I wonder if they can just simply not mount the MGU to the monocoque and only mount it to the engine. That should certainly stop transferring the vibrations. That would certainly qualify as a re-design.

[Farnborough]

Wazari wrote to me back in January that they struggle with the Aramco fuel because its composition causes oil dilution issues. Because of that and some sensor & software glitches, the 626 was not reliable and Honda wasn't pushing the PU above roughly 75%. Further struggle was the management/flattening of sudden torque peaks Honda experienced with their unique harvest/deploy sequences which were the cause of the destroyed gearboxes. Also the PU by itself didn't vibrate at all up until 15k RPMs, but as the K was mounted directly to the survival cell, the whole package hit some (dis)harmonic resonance and it was difficult to cure.

As you may remember the totally straight and ultra smooth driveline of the first Lexus LS400, even a couple of degrees can cause havoc if frequencies are happen to disturb/amplify themselves in unwanted places. I would have examined the entire chassis-engine integration from a cymatic POV to see where those harmful vibrations start to form.

That's weird, because publicly he said they can't go full power until the PU mounting is redesigned.

Though January was a long time ago, that might have been a transient issue.
Seeing Stroll's Monaco crash the torque problem seems to be persistent.

I wonder if they can just simply not mount the MGU to the monocoque and only mount it to the engine. That should certainly stop transferring the vibrations. That would certainly qualify as a re-design.

The motor IS the car's chassis. It's hard mounted to the monocoque in front of it, also to the monocoque behind it.

It's one whole structure when assembled, with all loading etc passing through this unified complete, bolted together unit.

In various images of PU when out of car you can see the regulated fix points, six front, 4 rear (think that's correct) that facilitate this. This is core design of composite material F1 cars, and has been for a long time.

With the amount of torque passing, positive & negative, through gear train at front of crankshaft, its highly unlikely there's remote mounting for MGU into this mechanical infrastructure.