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    • HeadGames Motorworks developing F80 M3 & F82 M4 performance cylinder head - S55 valve float issues

      HeadGames Motorworks is a very well regarded aftermarket cylinder head specialist. Recently they were tasked with upgrading the S55 cylinder from the BMW F80 M3 and F82 M4. Why? Well, the motor develops a valve float issue past 600 rear wheel horsepower.


      Many are not even aware of this issue but a tuner passed this information on to BimmerBoost as they were having trouble with cylinder head valve float in their high output S55.

      They turned to HeadGames Motorworks who is upgrading the cylinder head and apparently there is a quite a bit of room to gain power with increased flow.

      Expect more details when the cylinder head is wrapped up.

      Quote Originally Posted by HeadGames Motorworks
      We are about to get cracken on this BMW M4 Head. Expect to see some valve train, and head gains from the HeadGames gap assurance! Guys making 600+ will need to pay attention!

      Tons of potential in this BMW M4 Head!

      This article was originally published in forum thread: HeadGames Motorworks developing F80 M3 & F82 M4 performance cylinder head - S55 valve float issues started by Sticky View original post
      Comments 55 Comments
      1. subaru335i's Avatar
        subaru335i -
        Valve float is an RPM problem not really a power problem. Why do you mention 600hp?
      1. Tony@VargasTurboTech's Avatar
        Tony@VargasTurboTech -
        LOL at "valve float issue past 600WHP" Yes power is the cause of valve float. Do you even know what valve float is or what causes it? It has nothing to do with power production...
      1. Sticky2's Avatar
        Sticky2 -
        Click here to enlarge Originally Posted by subaru335i Click here to enlarge
        Valve float is an RPM problem not really a power problem. Why do you mention 600hp?
        Because of cylinder pressure at certain levels of boost.
      1. imola_shaun's Avatar
        imola_shaun -
        Yeah I don't think they mean 600whp equals valve lift.
      1. Sticky's Avatar
        Sticky -
        Click here to enlarge Originally Posted by Tony@VargasTurboTech Click here to enlarge
        LOL at "valve float issue past 600WHP" Yes power is the cause of valve float. Do you even know what valve float is or what causes it? It has nothing to do with power production...
        I'm not sure why you can not communicate like a normal human being. You could ask, hey, why do they feel there are issues past 600 horsepower and how was this found and under what circumstances?

        Considering how far behind you are on this platform you might want to learn rather than dismiss.

        Anyway, feel free to contact the cylinder head experts and tell them they are wrong.

        And if you think boost pressure doesn't have an effect on valve springs... then, um, lol at you?
      1. subaru335i's Avatar
        subaru335i -
        Click here to enlarge Originally Posted by Sticky Click here to enlarge
        I'm not sure why you can not communicate like a normal human being. You could ask, hey, why do they feel there are issues past 600 horsepower and how was this found and under what circumstances?

        Considering how far behind you are on this platform you might want to learn rather than dismiss.

        Anyway, feel free to contact the cylinder head experts and tell them they are wrong.

        And if you think boost pressure doesn't have an effect on valve springs... then, um, lol at you?
        I suppose you can say that boost pressure has some non zero effect but in practice even at very high boost it absolutely positively does not cause float.
        Valve control/float is a straight RPM problem with a given spring/cam combo.

        The intake valve closes about 120° Before Top Dead Center AND the piston is compressing the intake charge inside the cylinder (counteracting even very large boost) so there is little or no pressure difference between the top and bottom of the valve as it is closing. And as soon as it closes the cylinder pressure quickly builds causing the valve to close even harder.
        Tony is definitely an $#@! but if you reason through it you will realize that you are wrong.

        Headgames likely mentioned 600hp people "should keep an eye on this" because generally to get more power you start revving higher especially when you have small displacement and start getting to turbos that dont spool until higher and higher rpms.
      1. Sticky's Avatar
        Sticky -
        Click here to enlarge Originally Posted by subaru335i Click here to enlarge
        Tony is definitely an $#@! but if you reason through it you will realize that you are wrong.
        You might want to wait for HeadGames to chime in.
      1. Tony@VargasTurboTech's Avatar
        Tony@VargasTurboTech -
        I am communicating like a normal human being. Why can't you do your research before making a post that is completely incorrect, then arguing that it is not? Might want to wait for a company to chime in to say the S55 head is magic, and all of a sudden boost pressure causes valve float. This is gold. Again you literally do not know what valve float is if you are trying to put a power figure associated with valve float. No company that builds cylinders heads for a living would say that, something was miscommunicated somewhere along the way... Instead of simply saying this, you will defend your completely ignorant claim to the grave as you always do.

        This video may be of use to you. Notice the are calling out RPM stops, NOT power, nor anything to do with power...

      1. Sticky's Avatar
        Sticky -
        Click here to enlarge Originally Posted by Tony@VargasTurboTech Click here to enlarge
        Why can't you do your research before making a post that is completely incorrect, then arguing that it is not?
        I'm posting based on research others have actually done with real world work and testing on the cylinder head in question instead of arguing to try to satisfy my ego.

        Hilarious you are asking about research when you have none on the S55 cylinder head and are telling those who are doing research they are wrong.

        Twilight zone.
      1. Sticky's Avatar
        Sticky -
        Click here to enlarge Originally Posted by Tony@VargasTurboTech Click here to enlarge
        This video may be of use to you. Notice the are calling out RPM stops, NOT power, nor anything to do with power...
        It might be of use for you to know we discussed that video and topic back in 2010: https://www.boostaddict.com/showthre...in-slow-motion

        Might want to cut back on the know-it-all attitude that so often gets you embarrassed and then Chris has to cover your behind.
      1. Weehe's Avatar
        Weehe -
        Add another point to the valve float by rpm not power tally. Should it be 600whp at 8000+rpms?
      1. HeadgamesDave's Avatar
        HeadgamesDave -
        Hey guys!

        So to clear up the current conversation, I mentioned whp because of the amount of boost it takes to achieve this goal. A guy with 500whp does not need to run the amount of boost that a 600whp or above guy does. And boost not RPM is ABSOLUTELY apart of the equation when we are discussing a boosted car. If this were not true, we would be able to run the same valve spring in almost every 2JZ that we assemble. But, we cannot. The cars that make 2000whp or more and run 80psi or more run significantly more spring pressure to control the valve spring vs a car making half of that. NA car, RPM is the sole issue. Boosted, we have other things to worry about. Air on the back of the valve is weight. And these things are falling off WAY before 7k rpm.


        It came to my attention by my friend Kevin at Labworx while he was tuning some of these engines and power just drops off. When power just drops off via the rpm that is when we know float is or spring pressure is the cause. If it's flow issues it just won't make any more power, but if it is float it will drop off.

        I am a bad communicator but hopefully I made this understandable.

        So, when we got a cylinder head in and disassembled it you can see from my crude cell pics that the issue is indeed float. The problem with float is that it will progressively get worse. It gets worse because the valve seat angle, the 45 degree it sits seals to the valve seat with gets beat into it. Thus, making the spring height at top higher and this makes for less tension. This see-saw effect happens till it eventually breaks the valve or drops.

        What I am depicting in the photo's you can see the indentation in the valves. On the intake it's a little harder to see, but you will notice a shiny line around the head of the valve. That is where the indention is.



        Attachment 57714Attachment 57715



        The valve seat also takes a beating. You can see how shiny it is, but also notice that it is now concave at the 45 degree angle from the float.
        Attachment 57716

        and at the tip of the valve you can see the indention from it floating too. in the center.

        Attachment 57717


        this is off of a 700whp car. 30+psi. Low miles

        We are in the beginning stages of getting a spring kit available for it. The factory spring is only 50lbs on the seat and 150 open. Just trying to figure out what will work, not throw codes and be long lasting is the quandary.
      1. Sticky's Avatar
        Sticky -
        Click here to enlarge Originally Posted by HeadgamesDave Click here to enlarge
        It came to my attention by my friend Kevin at Labworx while he was tuning some of these engines and power just drops off. When power just drops off via the rpm that is when we know float is or spring pressure is the cause. If it's flow issues it just won't make any more power, but if it is float it will drop off.
        @kbaldi29 is great at giving technical details so I'm sure he wouldn't mind chiming in as well.
      1. Sticky's Avatar
        Sticky -
        Click here to enlarge Originally Posted by HeadgamesDave Click here to enlarge
        A guy with 500whp does not need to run the amount of boost that a 600whp or above guy does. And boost not RPM is ABSOLUTELY apart of the equation when we are discussing a boosted car. If this were not true, we would be able to run the same valve spring in almost every 2JZ that we assemble. But, we cannot. The cars that make 2000whp or more and run 80psi or more run significantly more spring pressure to control the valve spring vs a car making half of that. NA car, RPM is the sole issue. Boosted, we have other things to worry about. Air on the back of the valve is weight. And these things are falling off WAY before 7k rpm.
        Exactly this and thank you for your pictures and research which benefit the entire BMW tuning community.

        Air on the back of the valve requires stiffer springs for a variety of applications and as you stated valve float is not just an RPM thing:

        Applying 40 psi of boost (55 psi total) will give you a proportional increase in max pressure on the back of the valve, or about 62 psi. This will reduce valve seat spring pressure by 45 psi, or a bit more than the basic numbers suggest.

        You want a "safe" amount of seat pressure on the valve, because the valve will want to bounce on the seat as it deforms slightly, and bouncing on and off the seat is a big no no, leading to big trouble in a big hurry.
        This is an old LSX article on how you want to upgrade springs to combat valve float when boosting the motor but many of the principles are the same: https://www.lsxmag.com/tech-stories/...rviving-boost/
      1. Sticky's Avatar
        Sticky -
        Click here to enlarge Originally Posted by Weehe Click here to enlarge
        Should it be 600whp at 8000+rpms?
        He explained why the 600+ figure was put out as it is a general area where the amount of boost to reach that output (at least on the factory housings) starts to be an issue for the springs.
      1. kbaldi29's Avatar
        kbaldi29 -
        First I would like to state that in my book, Dave from Headgames is probably one of the most knowledgeable individuals in the industry when it refers to head stuff... more important than anything, didnt get stuck on the one car he got lucky with, instead after years of doing this, he kept proving his skill along the board... From 200whp honda heads to the fastest and most powerful cars in existence to this day, not quite sure?? The same way facts debated in this topic are nothing more than what google says, Im sure a quick google search will illustrate who Headgames is and perhaps what he has to say, is not really something to ignore...

        Not quite sure why the idea of valve floating seems to be so absurd, especially after long years or seeing, car after car with the s55 engine with odd graphs ending at or around 7k RPM, or just drastically dropping close to that RPM... maybe not alwys gets picked on right away, especially with a 700+whp number on the header deviating attention, but is silly to ignore this fact once it has been pointed out, perhaps, there is a solid issue here... a 7800+/- rpm revving capable engine with power showing only to 7k... I bet you is not because the dyno stopped short.

        We get lucky with the ability to control valve lift, advance and retard VVT on both cams on the S55 engines, this undeniably help to not improve but to hide with a band-aid what actually happens in the engine once boost starts to cross 27psi boost mark...

        My personal opinion is that considering all the necessary measures OEM nowadays has to use in order to comply regulations, is not surprising to hear a Head guy pointing out how low-pressure valve springs are in a modern DI engine, I mean... only happens to be implemented by all manufactures with DI engines in this days being sold in the US lol...

        Considering what Dave has illustrated here for us, not with assumptions but with facts, means that valve floating issue after X amount of boost/power is highly likel, is really nothing but the tip of the spear, other issued reversion and more term that I dont even understand completely at this point in life, are also possible in this scenario... What really is amazing here:

        -How is possible that took so long for someone to point this out??
        -And how can it be stupid to believe it once is shown to us?

        Excuse the grammar or other typical errors, kinda in a rush but had to say this before I lose the idea. lol
      1. Weehe's Avatar
        Weehe -
        I think the issue here is that we started the thread with a typical Tony post, resulting in a bit of hostility.

        I am not going to claim I can or can't see what is being pointed out in the pictures and I am not going to claim I even know average stuff about head work. The issue is the original post said:
        "Well, the motor develops a valve float issue past 600 rear wheel horsepower."
        These engines are able to make 600 whp at 5k rpms on stock frame turbos. Based on this people are seeing valve float all the way from 5-7.5k rpms? This is right around 27-30psi over that rpm range to make over 600 whp. Or are you going to say valve float is occurring above 6.5-7k rpms because power is not increasing anymore?

        The second issue I have is that if you are pushing stock frame turbos to over 27psi, you have a drastic increase in back pressure in the cylinder. Of course a 2000 whp supra would see valve float at 80psi on springs meant for 1000wph and 40psi. That 2000 whp supra has a turbo/manifold setup to reduce the back pressure into the cylinder.

        If you told me you are seeing valve float at 30 psi on a custom manifold single turbo but not stock frames at 30 psi, that would make sense. These posts are not denying valve float is happening, they are questioning the assumptions made on why it is happening and the assumed power/boost level responsible.

        I have a N55, which I'm told has the same head as a S55, so I have something to gain from this if it shows gains. I also am always interested in new things coming out but I have yet to hear of a S55 dropping a valve/broken spring.
      1. kbaldi29's Avatar
        kbaldi29 -
        I can def agree with all you said there, but let me clarify few points there or at least to my experience I know to be the case...

        -Indeed, I was referring to upgraded turbos at 27psi and above... The drop in power band can be and has been improved by adjusting timing and lift on the cams... But there is a point the normal rules dont apply... for example... at 27 psi you can make 650/650 whp/wtq... but you run 35psi and hp per pound reduces in comparison to what generated before the 27psi mark

        - There is a huge difference, to not say its not possible and argue away from the point of this post, stock turbos are not capable of pushing nowhere near 600whp... ethanol, race gas, jet fuel... whatever can be thrown in there... you cant change the efficiency of the turbos with a computer or mods... Before I get debated on the 600whp, lets make clear that spikes on the chart, dyno numbers without a graph or any 600 reading not being held for at least 1000rpms, is not considered a 600whp... that is called glory pull.

        - A single turbo setup has less disadvantage for irregularities compared to a twin setup, you have two+/- pulses for every stroke in single turbo setup compared to less than one for each stroke in a twin... This helps to compensate for less than ideal setups and will hide issues way easier... This completely putting aside the efficiency of a big single, its very hard to compare to the miracles stock location modified turbos are pulling off nowadays like the stage 2+ from pure... at the end of the day you push more air you will make more power, doesnt mean at all there is not an issue.

        -The 600whp typo on the tittle, all this means or Im gonna assume was intended to put in perspective what a spring with this specs normally would handle efficiently and trouble free, in what is considered to be a "capable" setup when for example... You build an engine for 800whp. There is rules to follow.

        Needless to say, this engines are beyond impressive in comparison to any other engine ever produced, we like to think they are beyond limits or at least the limits all other engines are subject to... without a doubt they are very good at making it work and what you can do with their features in engineering is above most... But lets not get that luxury blur our vision, S55 is not too far different from any other engine with pistons and rods going up and down... all of them relying on the same physics and principles to function, same basic rules that seem to be forget quite often just because one online example "squeezed" through this rules and pulled off what most didnt.
      1. Weehe's Avatar
        Weehe -
        Again, I am not saying valve float cant/isn't happening. But 27psi vs 35psi, psi to hp gain. This head flows for $#@!. Ported heads show gains and don't drop off power. This has been proven. Hopefully new springs just compound that.
      1. HeadgamesDave's Avatar
        HeadgamesDave -
        Click here to enlarge Originally Posted by kbaldi29 Click here to enlarge

        -The 600whp typo on the tittle, all this means or Im gonna assume was intended to put in perspective what a spring with this specs normally would handle efficiently and trouble free, in what is considered to be a "capable" setup when for example... You build an engine for 800whp. There is rules to follow.
        YES!

        If I were to have posted "7,000 rpm guys pay attention" would have no relevance.

        I didn't think everyone would take the number so personal.

        There is definitely float. That is not a theory, I laid it out in pics in detail. There is no other outside force that could cause such a condition. You can argue all you want in theory. Talking about reversion and manifolds and all kinds of $#@! but it won't take away the facts. It is what it is.

        the spring in the head now has 50lbs on the seat and 150 open. We would normally run 75-85lbs on the seat and 215-225 open with a valve size the same, power range, rpm, lift. (that is at 9.9mm lift like the BMW)

        We see the same issue with the ecoboost V6. Although they have less lift, the valve train gets beat to $#@! at same power level with stock springs. Nothing is usable after. Put good parts in it, IE our beehive spring kit and you can beat the $#@! out of it for years no issues.

        Not my first rodeo.