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  1. #226
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    Click here to enlarge Originally Posted by DBFIU Click here to enlarge
    PEI I have a question.

    From what I understand you are measuring port pressures? If this is the case, are the pressure transducers as close to the valve as possible? The reason I ask is, are you really going to be measuring helmholtz vibrations in the intake? If so that would be super cool, what sampling rate are you working with? To be able to capture each fluid vibration will need high frequency sampling.
    Helmholtz vibrations? I don't understand why you've zero'd in on this?

    The Helmholtz equation is used to solve harmonic calculations, as there are multiple orders of harmononics present inside of an intake manifold. A "Helmholtz resonator" is a calculated product of these equations used to boost the 3rd order harmonic which is desirable in some engine configurations.

    Will the pressure sensor measure these harmonics? Absolutely.

    Will the logging system have enough resolution to record them? Yes.

    Will the processing software focus on the harmonics? No, it will focus on the pressure trace in 1 cranking degree resolution at all RPMs. I'm sure the software can be configured to look at the 2nd, 3rd, and 4rth order harmonics specifically, but they are all a product of the combination of the engine RPM, intake length, and valve opening events.

    The pressure sensor data is a record of the effect of all 3 variables, which is a lot more valuable than just the harmonic information.

    There is a link posted previously in this thread which explains how the system works in great detail; better than I can with words.
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    Click here to enlarge Originally Posted by PEI330Ci Click here to enlarge
    Helmholtz vibrations? I don't understand why you've zero'd in on this?

    The Helmholtz equation is used to solve harmonic calculations, as there are multiple orders of harmononics present inside of an intake manifold. A "Helmholtz resonator" is a calculated product of these equations used to boost the 3rd order harmonic which is desirable in some engine configurations.

    Will the pressure sensor measure these harmonics? Absolutely.

    Will the logging system have enough resolution to record them? Yes.

    Will the processing software focus on the harmonics? No, it will focus on the pressure trace in 1 cranking degree resolution at all RPMs. I'm sure the software can be configured to look at the 2nd, 3rd, and 4rth order harmonics specifically, but they are all a product of the combination of the engine RPM, intake length, and valve opening events.

    The pressure sensor data is a record of the effect of all 3 variables, which is a lot more valuable than just the harmonic information.

    There is a link posted previously in this thread which explains how the system works in great detail; better than I can with words.
    I'll get back to this post after I take some engineering, physics, and math courses.

    Seriously though, great stuff guys.

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    Click here to enlarge Originally Posted by Sticky Click here to enlarge
    I'll get back to this post after I take some engineering, physics, and math courses.

    Seriously though, great stuff guys.
    He he..thanks...but this stuff isn't that complicated. However, my "retirement" plan is to go to University to understand all this stuff better...
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    Any updates?

    Have you ever considered adapting a direct injection system into the cylinder head?


    Zach K.

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    Click here to enlarge Originally Posted by yahweh Click here to enlarge
    Have you ever considered adapting a direct injection system into the cylinder head?
    Click here to enlarge

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    Click here to enlarge Originally Posted by yahweh Click here to enlarge
    Any updates?

    Have you ever considered adapting a direct injection system into the cylinder head?


    Zach K.
    I have no interest in plowing a couple hundred Gs into developing a system that targets fuel economy as the primary gain on a "hot rod". I'm well aware of what Aston Martin, Corvette Racing, and a few others went through, and have no desire in pursuing it.

    Click here to enlarge Originally Posted by Sticky Click here to enlarge
    Click here to enlarge
    I think that's the first time I've seen you use that emoticon.
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    Click here to enlarge Originally Posted by PEI330Ci Click here to enlarge
    I think that's the first time I've seen you use that emoticon.
    I'm not often confused by questions. Heh, surprised someone even suggested you go the direct injection route.

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    Click here to enlarge Originally Posted by Sticky Click here to enlarge
    I'm not often confused by questions. Heh, surprised someone even suggested you go the direct injection route.
    I should send you a technical article that detailed what Aston Martin had to do with their cylinder head to add DI. It was a lot of work....and I don't have the resources to even think about something like that. Heck, GM didn't....they went to Bosch and asked them for the system that Audi built for the LMP cars. A lot of people don't know this, but GM was actually the first in GT racing to run DI. I think they had it on the car for almost a year before someone else noticed......
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    Click here to enlarge Originally Posted by PEI330Ci Click here to enlarge
    I should send you a technical article that detailed what Aston Martin had to do with their cylinder head to add DI. It was a lot of work....and I don't have the resources to even think about something like that. Heck, GM didn't....they went to Bosch and asked them for the system that Audi built for the LMP cars. A lot of people don't know this, but GM was actually the first in GT racing to run DI. I think they had it on the car for almost a year before someone else noticed......
    I didn't even know GM was bothering with DI. Sure, e-mail me anything interesting: admin@germanboost.com

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    Click here to enlarge Originally Posted by Sticky Click here to enlarge
    I didn't even know GM was bothering with DI. Sure, e-mail me anything interesting: admin@germanboost.com
    I don't know that they are with road cars, but with the Le Mans Corvettes, they adopted pretty early on.
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    1 out of 1 members liked this post. Yes Reputation No
    Hey guys, I just browsed through this thread and I could not find any information on the stock compression size of the M54 combustion chamber - did you find out what it is by any chance?

    The M50/M52 heads are 33cc for comparison.

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    Click here to enlarge Originally Posted by Leo Click here to enlarge
    Hey guys, I just browsed through this thread and I could not find any information on the stock compression size of the M54 combustion chamber - did you find out what it is by any chance?

    The M50/M52 heads are 33cc for comparison.
    I'll go one further; I'll show you.

    The head:

    Click here to enlarge

    Plexi plate sealed to head:

    Click here to enlarge

    Starting to inject water:

    Click here to enlarge

    Just about there:

    Click here to enlarge

    Finished:

    Click here to enlarge

    Total of 34cc

    I actually went through this process a number of times because I just didn't believe the results when calculating the compression ratio.

    On the other side, here's the OEM M54B30 piston at TDC:

    Click here to enlarge

    It's actually 3.7mm down when centered...the piston rocks a bit in the bore...

    Setup to measure:

    Click here to enlarge

    Adding fluid:

    Click here to enlarge

    Done:

    Click here to enlarge

    Total of 17.4cc

    OEM head gasket is 0.030" thick, and approximately 85mm round.

    Do your calcs, and you'll find the compression ratio at 9.9:1.

    BMW specs 10.3:1 for the M54B30....I have no idea where that number comes from. This of course makes me question their other published compression ratios....
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    I'm not nearly at the same level, but maybe BMW's spec is after compression of the head gasket? Or is .030" after compression. Or is even enough to matter?


    This is all really great stuff, I would of never thought to do something like that to get actual measurement of volume in there. Thank you so much for sharing!

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    Click here to enlarge Originally Posted by SlicktopTTZ Click here to enlarge
    I'm not nearly at the same level, but maybe BMW's spec is after compression of the head gasket? Or is .030" after compression. Or is even enough to matter?


    This is all really great stuff, I would of never thought to do something like that to get actual measurement of volume in there. Thank you so much for sharing!
    Good question.

    What I've found is that the gasket doesn't change significantly in thickness when compressed, (Installed on the head) but the ridges formed around the chamber, oil passages, and water passages do.

    I'd show you a measurement of a new and used head gasket for reference....but I haven't taken a picture of it, and can't for at least a couple of more weeks.
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    Click here to enlarge Originally Posted by yahweh Click here to enlarge
    Any updates?

    Have you ever considered adapting a direct injection system into the cylinder head?


    Zach K.
    Click here to enlarge Originally Posted by Sticky Click here to enlarge
    I'm not often confused by questions. Heh, surprised someone even suggested you go the direct injection route.

    I am new to this forum and enjoy the technical pieces people have brought to the table. Much more data than a lot of other fourms. I respect you Sticky and your contributions, but I didn't suggest. Click here to enlarge

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    PEI330, Merry Christmas to you!!! And may I just say that your answer to my question was absolutely ridiculously fantastic. It is people like you that boost BMW enthusiasm. Click here to enlarge

    It's really strange that the end specs turn out to be under 10 compression when the OEM spec is 10.2:1 (not 10:3) - http://www.usautoparts.net/bmw/engines/m54.htm. It certainly does hurt the credibility of the official specifications.

    Perhaps its possible that when the car is at operating temperature, the piston expands slightly more than the steel cylinder liners and head to give an effective compression ratio of 10.2:1? Unlikely, but it's just a thought. Is it also possible that the head gaskets that come from the factory are thinner than the gaskets we buy off the shelf? Something here doesn't add up.
    Last edited by Leo; 12-26-2011 at 05:48 AM.

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    Yeah, I know.....holy thread revival.

    Adam, great work on the engine development! I love the scientific approach.


    On the M54 not being a great race motor, Im assuming its nasty bottom end "harmonics"/torsion. I have most of the BMW engines mapped out for harmonic orders, and the S52 is about as bad as you can get. Since M54 uses the same crank, its not surprising there have been so many issues.

    The S54 also has some major issues when used as a race motor. Teams usually had massive cooling ducts aimed at the torsional damper, and the damper was replaced regularly to prevent failure.

    Just thought I would point out the S54 isnt really a great race motor either as ironic as it sounds. At least it uses longer rods and a different style damper to help cope better.


    Any new development to share?

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    Smile

    Click here to enlarge Originally Posted by Wazzu70 Click here to enlarge
    Yeah, I know.....holy thread revival.
    You may get chastised from your bimmerforums FI brethren for thread revival... regardless of relevance. Not a big deal on these forums....even if you are from the Palouse. You add insight to the discussion and are contributing. Even though I am a UW alum.... I will still + rep you for adding personal insight even though much of the S54 paranoia you describe below would be more relevant a few years back Click here to enlarge

    Click here to enlarge Originally Posted by Wazzu70 Click here to enlarge
    The S54 also has some major issues when used as a race motor. Teams usually had massive cooling ducts aimed at the torsional damper, and the damper was replaced regularly to prevent failure.

    Just thought I would point out the S54 isnt really a great race motor either as ironic as it sounds.
    I humbly disagree. The S54 is an excellent motor that can sustain long periods at high rpm. However, the OEM damper has a very short lifespan. You could argue the OEM rod bearings have the same issue as well....but that is OT.

    Either you replace the harmonic balancer at a routine interval in race environments (40+ hours), have a custom one tuned to your application (ATI), or you will face catastrophic failure. That is it.

    Folks that race the S54 have figured this out a decade plus after release. New folks racing the S54 can address the rod-bearings and balancer for a $1000 and an afternoon of labor.

    The M54's achilles heel is not fixable by a box from Bimmerworld or VAC motorsports like the S54.

    Cheers,
    Mike

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    Click here to enlarge Originally Posted by MisterEm Click here to enlarge
    Folks that race the S54 have figured this out a decade plus after release. New folks racing the S54 can address the rod-bearings and balancer for a $1000 and an afternoon of labor.
    Doesn't sound like a big deal to me...

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    True, aftermarket dampers are not allowed in many of the classes the S54 was raced in.

    I suppose its more fair to say the S54 is a great race motor if you happen to be able to run an aftermarket damper. As designed, it still has a lot of issues.

    I dont have any data on the ATI dampers and how it holds up after a few races. Of course if you are running in a general class, the issue might not be as relevant due to the driver skill levels.

    It is very true the M54 is a lot worse off by design, and not as easily fixed! Too bad they did not produce a crank stroke between the 325 and 330. I suppose an M52b28 crank would work as a good midpoint stroke length.

    Yeah, guys from the Palouse are crazies Click here to enlarge That is definitely true!!

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    Wazzu,

    You speak the truth from the S54's historical perspective. I look at it more from a 2013 perspective. Its a fine motor to race with sub 3000 lbs. The S54 (like most I6's) is easy to wrench on, lots of aftermarket support and can be found for cheap. I don't find rod-bearings and balancer replacement to be a big deal on a car that lives at or above 8,000 rpm. Half the rod-bearing work is dropping the subframe. I see it as a wear item like clutches, rotors and tires. But that is just me.

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    Sounds good, I think we are in agreement! I should have clarified my original statement to include "with stock damper."

    If someone is campaigning a S54 powered racecar, the cost of an upgraded damper and bearings are the least of their financial concerns!

    If I decided to go 6cyl, I would without a doubt consider the S54! I didnt mean its a horrible engine or anything like that Click here to enlarge

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    Click here to enlarge Originally Posted by Wazzu70 Click here to enlarge
    I have most of the BMW engines mapped out for harmonic orders, and the S52 is about as bad as you can get. Since M54 uses the same crank, its not surprising there have been so many issues.
    Would you be able to elaborate on the data you have? What measurements were taken, and what analysis was done?
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    Click here to enlarge Originally Posted by PEI330Ci Click here to enlarge
    Would you be able to elaborate on the data you have? What measurements were taken, and what analysis was done?
    Not that I understand the charts, but maybe this info?

    http://forums.bimmerforums.com/forum...0#post25023350

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    Adam, I should say its a mathematical computation of the piston acceleration orders. These give a good idea where torsional problems will exist in the bottom end.

    Unfortunately I dont have the resources to fully map out the harmonics of a bottom end assembly.Im more than happy to post up what I've got.

    Any particular engines you want to see compared? Maybe ill do M54b25, M54b30 and S54? Seems like an appropriate comparison.

    [edit]The guy above liked to the format of the charts. I can compare whatever engines you want though and eliminate the engines you dont care about.

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