Honda Power Unit Hardware & Software

[godlameroso]

They're limited by the regulations at 18:1, so I'd say they're still well short of that. If I had to guess I'd put it between 13.5:1 and 15:1 more in line with what's being used.

[63l8qrrfy6]

While searching for some other things, I found this article, it's from RE. Maybe someone finds it interesting

The first prototype engine was run in the back of a development car at Mugello in September 2004, so the team could gather data on performance and the effects of the increased vibrations caused by a V8 on the surrounding systems. The engine development project team was run under Kazuo Sakurahara, who revealed to RE:
‘The most worrying problem would be a level of engine vibration which the design team had never experienced before.’
Honda RA806E
The vibration issue could potentially have lead to a range of problems that would keep both the engine and chassis design teams busy.

http://www.racecar-engineering.com/arti ... -revealed/

Back to my first search: anybody can enlighten me what the compression rates are in the current Honda engine? North of 18:1?

V8 vibrations took everyone by surprise. Cosworth CAs were shedding scavenge pumps and other ancilliaries left and right. They had to use multiphase bolts to keep them together.

[Squid]

The Honda engine has a very distinctive rumbling sound when accelerating out of corners. Other engines sound much smoother. What could be causing this noise?

[flexcon]

The Honda engine has a very distinctive rumbling sound when accelerating out of corners. Other engines sound much smoother. What could be causing this noise?

I remember reading some replies that suggested in was either Cylinder cutting or the sound of the firing order.

I personally love the sound, almost like traction control era

[bigblue]

They had to use multiphase bolts to keep them together.

What's a multiphase bolt ?

[rscsr]

They had to use multiphase bolts to keep them together.

What's a multiphase bolt ?

It is a bolt, that kinda acts like a spring. Therefore vibrations can't loosen the bolts so easily.
I couldn't find the correct english Wikipedia, but here is the corresponding german Wikipedia: Dehnschraube

[Craigy]

They had to use multiphase bolts to keep them together.

What's a multiphase bolt ?

It's a bolt made of a type of multi-phase steel. Google for "steel phase diagram".

The phase of steel is to do with the structure of the crystals and how they are joined together.

Edit: look at figure 3 here https://www.researchgate.net/publicatio ... rip_steels

[Craigy]

While searching for some other things, I found this article, it's from RE. Maybe someone finds it interesting

The first prototype engine was run in the back of a development car at Mugello in September 2004, so the team could gather data on performance and the effects of the increased vibrations caused by a V8 on the surrounding systems. The engine development project team was run under Kazuo Sakurahara, who revealed to RE:
‘The most worrying problem would be a level of engine vibration which the design team had never experienced before.’
Honda RA806E
The vibration issue could potentially have lead to a range of problems that would keep both the engine and chassis design teams busy.

http://www.racecar-engineering.com/arti ... -revealed/

Back to my first search: anybody can enlighten me what the compression rates are in the current Honda engine? North of 18:1?

V8 vibrations took everyone by surprise. Cosworth CAs were shedding scavenge pumps and other ancilliaries left and right. They had to use multiphase bolts to keep them together.

The Honda was particularly bad for vibration, especially in comparison to the comparable MB engine.

[Craigy]

They had to use multiphase bolts to keep them together.

What's a multiphase bolt ?

It is a bolt, that kinda acts like a spring. Therefore vibrations can't loosen the bolts so easily.
I couldn't find the correct english Wikipedia, but here is the corresponding german Wikipedia: Dehnschraube

If I understand the robotranslation from German into English, what you are describing is called a stretch bolt in English English, or commonly "torque to yield" in American English.

Stretch bolts are not made of multiphase steel - they are made of mild steel in my experience (Rover K-series).

[ziggy]

The Honda engine has a very distinctive rumbling sound when accelerating out of corners. Other engines sound much smoother. What could be causing this noise?

I remember reading some replies that suggested in was either Cylinder cutting or the sound of the firing order.

I personally love the sound, almost like traction control era

From the article:

But perfecting the software to allow the advantages of HCCI principal at appropriate revs and loads, but switching to conventional ignition outside of those limits has proved feasible. The characteristic ‘misfire’ sound of the Honda on part throttle is believed to be the audible giveaway of the changeover point between the two modes.

The effect can also be heard – but less aggressively - on the Ferrari. With the Mercedes however, there is no aural evidence. It’s believed the Mercedes engine has featured this technology from the start in 2014, that it was also incorporated into Honda’s first engine last year and that Ferrari adopted the technology last year. Renault would this be the last of the four manufacturers to introduce it. Although details are sketchy at this point, it’s clear that this new technology has been a major part of the F1 power war in the hybrid turbo formula.

http://www.motorsportmagazine.com/opini ... wer-secret

[rscsr]

What's a multiphase bolt ?

It is a bolt, that kinda acts like a spring. Therefore vibrations can't loosen the bolts so easily.
I couldn't find the correct english Wikipedia, but here is the corresponding german Wikipedia: Dehnschraube

If I understand the robotranslation from German into English, what you are describing is called a stretch bolt in English English, or commonly "torque to yield" in American English.

Stretch bolts are not made of multiphase steel - they are made of mild steel in my experience (Rover K-series).

If that is really the case, than I don't know what the fuss is about. Normal bolts are available with strength class 12.9 (yield strength of 1 080 MPa) (for not even 0.5€ per bolt) usually in stock. And even up to 16.9 is standard.
I kinda would have been pretty surprised if they used anything less than grade 5 Titanium bolts, which have a better strength per weight than even the best steel bolts.
Therefore I kinda assumed that a multiphase bolt meant the construction and not the material.

[Craigy]

It is a bolt, that kinda acts like a spring. Therefore vibrations can't loosen the bolts so easily.
I couldn't find the correct english Wikipedia, but here is the corresponding german Wikipedia: Dehnschraube

If I understand the robotranslation from German into English, what you are describing is called a stretch bolt in English English, or commonly "torque to yield" in American English.

Stretch bolts are not made of multiphase steel - they are made of mild steel in my experience (Rover K-series).

If that is really the case, than I don't know what the fuss is about. Normal bolts are available with strength class 12.9 (yield strength of 1 080 MPa) (for not even 0.5€ per bolt) usually in stock. And even up to 16.9 is standard.
I kinda would have been pretty surprised if they used anything less than grade 5 Titanium bolts, which have a better strength per weight than even the best steel bolts.
Therefore I kinda assumed that a multiphase bolt meant the construction and not the material.

I'm not sure what the regs were back in the days of the 2.4 Honda V8, but these days Ti is a banned material for fasteners on the PUs - they have to be alloys of iron/cobalt/nickel.
Ti is allowed on the chassis, but not the engine.

[Tommy Cookers]

tightening torque (friction) is a poor determiner of clamping load
torque-to-yield is a good determiner of clamping load

combined with a longer plastic range than the 'strongest' (highest UTS) materials can provide ? .....
a clamping load that is maintained throughout a high cyclic loading
even with a short bolt

still don't believe mild steel (eg stretch-to-yield as in Ford CVH)
a stronger material than MS but not heat treated to highest UTS ?

[GoranF1]

Spec 4 not introduced here because it "did not meet target"

[bigblue]

Saw this Japanese report at jp.motorsport.com on the autosport forum, posted by user Hasika. He, and the machine translated version of the report, says that Spec 4 is still under development, maybe available soon, but not yet reaching the desired power target.