F1 V6 90 degree vibration questions

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Honda Porsche fan
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F1 V6 90 degree vibration questions

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This might have been discussed years ago on here but I was wondering what are the ways F1 engine manufacturers have been able to remove as much vibration out of the V6 90 degree engines? I'm asking about perfect primary and secondary balance and is it possible to achieve that in a 90 degree V6?

According to wiki, this is what some automakers did with their road cars with 90 degree V6 engines...

"The downsides of a 90 degree design are a wider engine which is more vibration-prone than a 60 degree V6. The initial 90 degree V6 engines (such as the Buick Fireball V6 engine) had three shared crankpins arranged at 120 degrees from each other, due to their origins from the V8 engines. This resulted in an uneven firing order, with half of the cylinders using a firing interval of 90 degrees and other half using an interval of 150 degrees. The uneven firing intervals resulted in rough-running engines with "unpleasant" vibrations at low engine speeds.

Several modern 90 degree V6 engines reduce the vibrations using split crankpins offset by 30 degrees between piston pairs, which creates an even firing interval of 120 degrees for all cylinders.[4] For example, the 1977 Buick 231 "even-fire" V6 engine was an upgraded version of the Buick Fireball engine with a split-pin crankshaft to reduce vibration by achieving an even firing order.[5]: 16 [7] Such a 'split' crankpin is weaker than a straight one, but modern metallurgical techniques can produce a crankshaft that is adequately strong. A balance shaft and/or crankshaft counterweights can be used to reduce vibrations in 90 degree V6 engines"


Did F1 engine manufactures solve the vibration issues using split crankpins offset by 30 degrees between piston pairs and a balance shaft and/or crankshaft counterweights ?

The Acura/Honda AR35TT race engine used in Acura ARX-05 Daytona DPi Prototype has a 60 degree V6 engine.

Would there have been advantages if F1 went with 60 degree or 120 or 180 flat boxer 6's?

saviour stivala
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Re: F1 V6 90 degree vibration questions

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Split crankpins are not allowed by the rules as they will constitute a different crankpin for each con-rod. As to the low-speed vibration of a 90 degree v-6, the idle speed of the formula one v-6 is nearer to the maximum speed of the road going v-6. Counterbalances are used in a formula one crankshaft.

Tommy Cookers
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Re: F1 V6 90 degree vibration questions

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Honda Porsche fan wrote:
16 Sep 2022, 06:09
....I'm asking about perfect primary and secondary balance and is it possible to achieve that in a 90 degree V6?
... Would there have been advantages if F1 went with 60 degree or 120 or 180 flat boxer 6's?
no & no

F1's 3 thow 90 deg V6 have primary (force) balance and secondary (force) balance
and primary moment imbalance cancelled in the crankshaft by counterweights
and secondary moment imbalance (not cancellable in the crankshaft)
yes they have uneven firing intervals (unimportant)
they are a good package

a 3 throw 60 deg V6 isn't better balancewise and has uneven firing intervals and isn't such a good package
a 3 throw 120 deg V6 isn't better balancewise but has even firing intervals - and isn't such a good package
(current 120 deg Ferrari & McL road cars have reported 'primary imbalance' seemingly not cancellable in the crankshaft)
a 3 throw 180 deg 6 isn't better balancewise and has uneven firing intervals and is a poor package

the points above aren't relevant to road cars
Buick started the road 90 deg 3 throw V6 c.1965
all of the few road and competition V6s had been 6 throw till the dominant 1961 3 throw 120 deg F1 Ferrari

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Re: F1 V6 90 degree vibration questions

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wrote:
F1's 3 thow 90 deg V6 have primary (force) balance and secondary (force) balance
and primary moment imbalance cancelled in the crankshaft by counterweights
and secondary moment imbalance (not cancellable in the crankshaft)
yes they have uneven firing intervals (unimportant)

they are a good package
Have automakers over the years tried to fix or remedy the issues highlighted in bold above and if so what were they?

Would split crankpins with a different crankpin for each con-rod cancel the secondary imbalance of a 90 degree V6?
Last edited by Honda Porsche fan on 17 Sep 2022, 00:41, edited 1 time in total.

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Re: F1 V6 90 degree vibration questions

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saviour stivala wrote:
16 Sep 2022, 08:16
Split crankpins are not allowed by the rules as they will constitute a different crankpin for each con-rod. As to the low-speed vibration of a 90 degree v-6, the idle speed of the formula one v-6 is nearer to the maximum speed of the road going v-6. Counterbalances are used in a formula one crankshaft.
Why did the FIA not allow or want F1 engine manufacturers to have/use a different crankpin for each con-rod?

Are there advantages and disadvantages to using a different crankpin for each con-rod?

Are there any racing series (Indycar, Le Mans, NHRA drag, MotoGP, WSBK) that allow engine manufacturers to use a different crankpin for each con-rod?

Greg Locock
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Re: F1 V6 90 degree vibration questions

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Yes they have. In 1924 Lanchester introduce the balance shaft to eliminate problems with 2E. 1E is resolved by 2 plane balancing. With a 90 degree V6 (spit) you also get a 1.5E rocking couple which has killed more than one vehicle program. You could solve that with another balance shaft.

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Re: F1 V6 90 degree vibration questions

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I'm a little confused on the exact displacement in liters and cubic inches of F1 V6 inches...

On wiki, it says that the Mercedes V6 is 1.6 L (98 cu in)...

https://en.wikipedia.org/wiki/Mercedes_ ... One_engine

But, a 1600 cc is 97.638 cubic inches...

https://convertoctopus.com/1600-cubic-c ... bic-inches

Are F1 engines set at 1.599cc or 1,600cc? Are they 97.6 cu in or 98 cu in? If they are 98 cu in then what is their exact cc ?

gruntguru
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Re: F1 V6 90 degree vibration questions

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I am not sure we should care. 98 c.i. is only 0.37% bigger than 97.638 c.i.

The FIA is a European body and like all of the world outside the USA, engine displacement is defined in metric units. Web sites quoting the displacement in C.I. are doing so for the benefit of those few who prefer their engines that way - in which case
"a little less than 100 c.i." is probably all the precision they want.

The displacement upper limit is precisely 1.6 L (so a 98 c.i. engine would be illegal).
The displacement lower limit is precisely 1.590 L

https://www.fia.com/sites/default/files ... 9-13_0.pdf
je suis charlie

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Re: F1 V6 90 degree vibration questions

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Is it possible to use a flat-6 boxer engine as a stressed chassis load bearing member with no space frame or trunnions like V engines can?

Has any team used a flat engine in F1 as a stressed member with no space frame?

Tommy Cookers
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Re: F1 V6 90 degree vibration questions

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Honda Porsche fan wrote:
20 Sep 2022, 22:33
.... Has any team used a flat engine in F1 as a stressed member with no space frame?
maybe the question wasn't what should have been asked ....
Flat-12s - Ferrari 1965, 1970-79, Brabham-Alfa-Romeo 1976-8, Alfa Romeo 1978-9 and Coloni-Subaru 1990

of course some older F1 cars had solid-mounted engines and twin-tube frames
even the oldest car in F1, the Delage made c.1927

EDIT
the Alfa Romeo tipo 160 was a 4 wd flat 12 (designed for 1954 F1 but not completed) - it had no chassis
(this site's picture isn't a 160 - it's the 159 muletta)
Last edited by Tommy Cookers on 21 Sep 2022, 18:44, edited 1 time in total.

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Re: F1 V6 90 degree vibration questions

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Tommy Cookers wrote:
21 Sep 2022, 00:41
Honda Porsche fan wrote:
20 Sep 2022, 22:33
.... Has any team used a flat engine in F1 as a stressed member with no space frame?
maybe the question wasn't what should have been asked ....
Flat-12s - Ferrari 1965, 1970-79, Brabham-Alfa-Romeo 1976-8, Alfa Romeo 1978-9 and Coloni-Subaru 1990

of course some older F1 cars had solid-mounted engines and twin-tube frames
even the oldest car in F1, the Delage made c.1927
Thank you, yes, I'm aware of the flat engines in F1's history. I was wondering how those flat engines were attached to the chassis/bulkhead/gearbox and if they needed a space frame. One of the drawbacks of inline engines is the need of a space frame and Adrian Newey saying space frames reduce chassis rigidity.

Jolle
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Re: F1 V6 90 degree vibration questions

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Honda Porsche fan wrote:
21 Sep 2022, 01:39
Tommy Cookers wrote:
21 Sep 2022, 00:41
Honda Porsche fan wrote:
20 Sep 2022, 22:33
.... Has any team used a flat engine in F1 as a stressed member with no space frame?
maybe the question wasn't what should have been asked ....
Flat-12s - Ferrari 1965, 1970-79, Brabham-Alfa-Romeo 1976-8, Alfa Romeo 1978-9 and Coloni-Subaru 1990

of course some older F1 cars had solid-mounted engines and twin-tube frames
even the oldest car in F1, the Delage made c.1927
Thank you, yes, I'm aware of the flat engines in F1's history. I was wondering how those flat engines were attached to the chassis/bulkhead/gearbox and if they needed a space frame. One of the drawbacks of inline engines is the need of a space frame and Adrian Newey saying space frames reduce chassis rigidity.
The addition of a sub-frame around the engine (what type of engine doesn't matter) will add to the rigidity and not reduce it. Current PU's already have a (small) sub/space frame to add to the strength.

See it in the same way gearboxes are build now. They use to be a structural part of the car but now they have a separate casing that adds to it rigidity, flexibility and saves weight. This can also be done with an engine if the casings don't need to pull this double duty.

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Re: F1 V6 90 degree vibration questions

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Jolle wrote:
21 Sep 2022, 15:50
Honda Porsche fan wrote:
21 Sep 2022, 01:39
Tommy Cookers wrote:
21 Sep 2022, 00:41

maybe the question wasn't what should have been asked ....
Flat-12s - Ferrari 1965, 1970-79, Brabham-Alfa-Romeo 1976-8, Alfa Romeo 1978-9 and Coloni-Subaru 1990

of course some older F1 cars had solid-mounted engines and twin-tube frames
even the oldest car in F1, the Delage made c.1927
Thank you, yes, I'm aware of the flat engines in F1's history. I was wondering how those flat engines were attached to the chassis/bulkhead/gearbox and if they needed a space frame. One of the drawbacks of inline engines is the need of a space frame and Adrian Newey saying space frames reduce chassis rigidity.
The addition of a sub-frame around the engine (what type of engine doesn't matter) will add to the rigidity and not reduce it. Current PU's already have a (small) sub/space frame to add to the strength.

See it in the same way gearboxes are build now. They use to be a structural part of the car but now they have a separate casing that adds to it rigidity, flexibility and saves weight. This can also be done with an engine if the casings don't need to pull this double duty.
Does this in any way have to do with the addition of KERS/hybrid (MGU-H/K) the last few years as to why F1 teams now use space frames or did F1 teams find that these new space frames add rigidity regardless if race cars have MGU-H/K or not?

Do current Indycars and LMP prototype cars have spaceframes?

Jolle
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Joined: 29 Jan 2014, 22:58
Location: Dordrecht

Re: F1 V6 90 degree vibration questions

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Honda Porsche fan wrote:
21 Sep 2022, 20:01
Jolle wrote:
21 Sep 2022, 15:50
Honda Porsche fan wrote:
21 Sep 2022, 01:39


Thank you, yes, I'm aware of the flat engines in F1's history. I was wondering how those flat engines were attached to the chassis/bulkhead/gearbox and if they needed a space frame. One of the drawbacks of inline engines is the need of a space frame and Adrian Newey saying space frames reduce chassis rigidity.
The addition of a sub-frame around the engine (what type of engine doesn't matter) will add to the rigidity and not reduce it. Current PU's already have a (small) sub/space frame to add to the strength.

See it in the same way gearboxes are build now. They use to be a structural part of the car but now they have a separate casing that adds to it rigidity, flexibility and saves weight. This can also be done with an engine if the casings don't need to pull this double duty.
Does this in any way have to do with the addition of KERS/hybrid (MGU-H/K) the last few years as to why F1 teams now use space frames or did F1 teams find that these new space frames add rigidity regardless if race cars have MGU-H/K or not?

Do current Indycars and LMP prototype cars have spaceframes?
F1 is all about maximise efficiency. If a space frame or sub frame is better in stiffness to weight, it will be used. Other racing series like IndyCar use standerd (and in the case of IndyCar very old) tech, so there is much less of a push of efficiency.
don't know if teams used support frames during the V8 or V10 days, google for pics I suggest.

NL_Fer
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Re: F1 V6 90 degree vibration questions

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Would the ultra lightweight pistons reduce vibration and the high rpm, stay out of any resonance frequency?