current F1 turbo inlet and exhaust valve sizes

All that has to do with the power train, gearbox, clutch, fuels and lubricants, etc. Generally the mechanical side of Formula One.
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johnny comelately
110
Joined: 10 Apr 2015, 00:55
Location: Australia

current F1 turbo inlet and exhaust valve sizes

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What are the inlet and exhaust valve sizes for any of the turbo engines, either from the 80's or the current formula?

This is to ponder the exhaust size required to effectively remove the extra atmospheres of inlet charge.
it also relates to port sizes in relation to valve size.
i have deliberately not related this to inlet or exhaust phenomena or hysteresis.

Any facts known?

Brian Coat
99
Joined: 16 Jun 2012, 18:42

Re: current F1 turbo inlet and exhaust valve sizes

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Got a ruler?

http://www.k20a.org/upload/HondaRA168EEngine.pdf

Even without scaling, you can see from Fig. 1 that the valves are in 'normal 4V/cyl racing engine' ratios to the bore and each other.

This will also be the case for the current era, I expect.

johnny comelately
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Joined: 10 Apr 2015, 00:55
Location: Australia

Re: current F1 turbo inlet and exhaust valve sizes

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thanks Brian, yes i have read that paper and have tried to measure the valve heads.
to me it was not something to rely on.
the current engines seem to be quite different going by the exhaust pipe sizes.
i am also trying to relate it to the inlet pressure and rpm.
along the same reasons to find these answers, do you know the increase in stinger diameter when changing to methanol fuel?

Brian Coat
99
Joined: 16 Jun 2012, 18:42

Re: current F1 turbo inlet and exhaust valve sizes

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You don't need to measure it, the old Honda drg. just confirms you can assume similar bore/inlet/exh size ratios to nat. asp. 4V.

Re Methanol, if you are referring to the effect on exhaust to inlet mass flow due to low stoichiometric AFR of methanol, in practice there sometimes is none because methanol fuel is sometimes injected upstream of the intake valve for charge cooling purposes, making inlet and exh valve mass flows essentially the same.
Last edited by Brian Coat on 29 Jun 2015, 11:09, edited 2 times in total.

Pumaracing
8
Joined: 09 Apr 2014, 06:59

Re: current F1 turbo inlet and exhaust valve sizes

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johnny comelately wrote:What are the inlet and exhaust valve sizes for any of the turbo engines, either from the 80's or the current formula?

This is to ponder the exhaust size required to effectively remove the extra atmospheres of inlet charge.
it also relates to port sizes in relation to valve size.
i have deliberately not related this to inlet or exhaust phenomena or hysteresis.

Any facts known?
I infer you might be thinking the exhaust valves need to be bigger at the expense of inlet valve size to remove "the extra atmospheres of inlet charge". If so then why do you think this is and could you be wrong?

gruntguru
563
Joined: 21 Feb 2009, 07:43

Re: current F1 turbo inlet and exhaust valve sizes

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Pumaracing wrote:
johnny comelately wrote:What are the inlet and exhaust valve sizes for any of the turbo engines, either from the 80's or the current formula?

This is to ponder the exhaust size required to effectively remove the extra atmospheres of inlet charge.
it also relates to port sizes in relation to valve size.
i have deliberately not related this to inlet or exhaust phenomena or hysteresis.

Any facts known?
I infer you might be thinking the exhaust valves need to be bigger at the expense of inlet valve size to remove "the extra atmospheres of inlet charge". If so then why do you think this is and could you be wrong?
There are many cases where valve size ratios are changed slightly in favour of the exhaust valve, when an engine is supercharged. This particulaly the case when a NA engine has a large bias towards the inlet valve. David Vizard's early book on cylinder head modification talks about ex/in ratio and states that supercharged engines will generally need about a 5% shift in favour of the exhaust.

I can speak from personal experience. A turbocharged A series Cooper S engine running 30 PSI boost (3 bar ABS) was raced with two different cylinder heads. Both heads were expertly prepared. Both had maximum size valves (nearly touching each other) on the same spacing. One had standard Cooper S valve sizes and the other had equal size inlet and exhaust.

The equal-valve head was vastly superior. It made more power at all rpm with the same boost. The turbo spooled earlier in the rev range.

In general though, I would think that an F1 engine with highly developed port flow, similar manifold pressure in intake and exhaust, wave tuned exhaust manifold etc, would use valve sizes similar to NA.
je suis charlie

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Abarth
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Joined: 25 Feb 2011, 19:47

Re: current F1 turbo inlet and exhaust valve sizes

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In these very engines, my estimate is that the overall intake/exhaust stroke losses should be minimized, and there is less need to chase maximum volumetric efficiency.
Wouldn't therefore the same mechanisms be applied as you saw with this turbocharged Cooper S, i.e. almost equal intake and exhaust valve sizes?

Vortex37
20
Joined: 18 Mar 2012, 20:53

Re: current F1 turbo inlet and exhaust valve sizes

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gruntguru wrote:
gruntguru wrote:I infer you might be thinking the exhaust valves need to be bigger at the expense of inlet valve size to remove "the extra atmospheres of inlet charge". If so then why do you think this is and could you be wrong?
There are many cases where valve size ratios are changed slightly in favour of the exhaust valve, when an engine is supercharged. This particulaly the case when a NA engine has a large bias towards the inlet valve. David Vizard's ......snip
There is another possible aspect. Different sizes within each type (exhaust/inlet). You mentioned Vizard, so it's worth recalling his 'polyquad' head. With the current relatively small F1 bore size, the need to accommodate DI, and the possibility of lean burn/stratified charge combustion topology, it might be worth a revisit. His idea of separate paths to each inlet valve, each with different dimensions, to give low volume high velocity flow, at low rpm might have been especially useful in 2014, where variable inlet length was banned. Just a thought!

Original polyquad article by Vizard

johnny comelately
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Joined: 10 Apr 2015, 00:55
Location: Australia

Re: current F1 turbo inlet and exhaust valve sizes

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Brian Coat wrote:You don't need to measure it, ghe ild Honda drg. just confirms you can assume similar bore/inlet/exh size ratios to nat. asp. 4V.

Re Methanol, if you are referring to the effect on exhaust to inlet mass flow due to low stoichiometric AFR of methanol, in practice there often is none because methanol fuel is often injected upstream of the intake valve for charge cooling purposes, making inlet and exh valve mass flows essentially the same.
Brian, with the extra power produced from methanol, the exhaust needs to be quite a lot bigger. not doing this on a rotax engine resulted in burnt pistons.
i assume a similar scenario for charged engines.
just what is adequate to prevent unknown power not being generated?

Tommy Cookers
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Joined: 17 Feb 2012, 16:55

Re: current F1 turbo inlet and exhaust valve sizes

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gruntguru wrote: ....... In general though, I would think that an F1 engine with highly developed port flow, similar manifold pressure in intake and exhaust, wave tuned exhaust manifold etc, would use valve sizes similar to NA.
BMW won turbo F1 with a nominally stock-block 4 slightly destroked from the N/A F2 using the 1600 cc block
after N/A F2 went 2000 cc free-design Renault made their sportscar race V6 into a turbocharged outright contender for Le Mans
this was destroked for 1500 cc F1 and so had a very high bore:stroke ratio
Honda's 2000 cc F2 dominant V6 had such already, and had extreme b:s ratio when destroked to be their early turbo F1

the point being that the F1 turbo V6s started out with rather huge valve areas (due to their b:s ratios)
also there was a lot of low-hanging development fruit to be gathered before worrying about optimising valve area ratio

as fuels evolved and boost limits came engines were redesigned to much lower b:s ratios
Honda went from 90 mm bore to 82 mm bore, and eventually to 79 mm bore
forcing much reduced valve areas
so only now had inlet:exhaust area ratio become important ?

rules and fuels changed almost overnight then, are we sure that Honda had for 1988 optimised their ratio of inlet:exhaust area ?
or that the drawings in the SAE paper show an optimised arrangement (not an earlier or intentionally misleading one) ?

iirc the Gilles Simon article in RCE 2+ years ago predicted a reduced valve area to allow the best CR and combustion chamber
this might determine the current inlet:exhaust area ratio (the inlet valve being the big factor in this case)

Brian Coat
99
Joined: 16 Jun 2012, 18:42

Re: current F1 turbo inlet and exhaust valve sizes

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I understand that the Ferrari/Shell paper presented at this years Vienna symposium suggested that exhaust valves have grown a lot relative to intakes in the current turbo+MGU era.

So my Honda-based guess above is looking fairly rubbish :lol:

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godlameroso
309
Joined: 16 Jan 2010, 21:27
Location: Miami FL

Re: current F1 turbo inlet and exhaust valve sizes

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gruntguru wrote:
Pumaracing wrote:
johnny comelately wrote:What are the inlet and exhaust valve sizes for any of the turbo engines, either from the 80's or the current formula?

This is to ponder the exhaust size required to effectively remove the extra atmospheres of inlet charge.
it also relates to port sizes in relation to valve size.
i have deliberately not related this to inlet or exhaust phenomena or hysteresis.

Any facts known?
I infer you might be thinking the exhaust valves need to be bigger at the expense of inlet valve size to remove "the extra atmospheres of inlet charge". If so then why do you think this is and could you be wrong?
There are many cases where valve size ratios are changed slightly in favour of the exhaust valve, when an engine is supercharged. This particulaly the case when a NA engine has a large bias towards the inlet valve. David Vizard's early book on cylinder head modification talks about ex/in ratio and states that supercharged engines will generally need about a 5% shift in favour of the exhaust.

I can speak from personal experience. A turbocharged A series Cooper S engine running 30 PSI boost (3 bar ABS) was raced with two different cylinder heads. Both heads were expertly prepared. Both had maximum size valves (nearly touching each other) on the same spacing. One had standard Cooper S valve sizes and the other had equal size inlet and exhaust.

The equal-valve head was vastly superior. It made more power at all rpm with the same boost. The turbo spooled earlier in the rev range.

In general though, I would think that an F1 engine with highly developed port flow, similar manifold pressure in intake and exhaust, wave tuned exhaust manifold etc, would use valve sizes similar to NA.
My experience mirrors this sentiment, a well known trick for making more power with boosted Hondas is to use oversized exhaust valves and position the seat so that the valve stem installed height is at the height spec limit.
Saishū kōnā

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