Cts-v 388 blow up video
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Thread: Cts-v 388 blow up video

  1. #1
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    Cts-v 388 blow up video

    2009 CTS-V A6 White Diamond 388
    Derek Dunbar tuning
    GP Tuning
    Jokerz Performance
    Late Model engines
    WCCH

  2. #2
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    Quote Originally Posted by CUIN9SEC View Post
    -assuming this is your car and engine-
    Sorry to hear about this George.
    The engine sounded good, like it was about 50-Cubic Inches Larger than a 388..lol

    What RPM's were you shifting at?
    What times and mph did you get?

    I noticed that the pistons were flat tops with gas ports.
    What was the 'Quench Gap'?

    I ask this because of the burn pattern I see on the piston
    you show at 4.05 minutes into the video.

    I see what appears to be a lot of 'Squish Velocity'.

    -note-
    Squish velocity is the speed at which air is displaced from between
    the piston and head surface as the piston approaches TDC.
    It is the result of three factors: clearance, area and piston speed.


    Also, what type of fuel?

    How did they set the deck height and quench gap?
    Rod length, piston pin location, deck the block, etc.

    See, you post a video and we play 64-Questions..

    --------------------------------------------------

    You said your going to build another 388 cid.
    Nice engine combo. . . .

    You said your going use a better con rod, an I-Beam.
    Good decision.

    You said your moving up to an LS7 Head.

    Good decision as you can generally get more air / cfm through
    the cylinder head by convergence lift, on up to 0.600" valve lift.

    With the above in mind; if you desire too, use the 2.204" valve and
    bore the engine to 4.155". Have the combustion chamber fitted for
    the 4.155" bore and shaped / contoured to get as much air into
    the cylinder by convergence lift as you can. Convergence lift for
    a 2.204" intake valve will be 0.551" of 'Valve Lift'.

    -note- make sure you have the block checked for core shift
    before boring it to 4.155".

    Just for the record. . .
    The earlier blocks were crap in this department,
    but the new blocks are good. The blocks they are making today
    can be bored to 4.185" and are good for 1,500 fwHP.

    Or consider a Dart block instead. . .

    If you do this correctly you can get about 385 cfm to 395 cfm
    through the head by 0.551", to 0.600" valve lift.

    Don't put a camshaft in it with over 0.665" valve lift.
    The heads simply go turbulent by about 0.635" lift on
    a 'Running Engine. And that is with a good head!

    Lesser heads won't flow past about 0.585" of valve lift.

    That's one of the reasons so many camshaft grinders don't
    grind cams with much more valve lift.

    0.665" gross lift, less all valve train flex and geometric
    losses, will most likely generate a 'Net' valve lift of
    about 0.635". Effective cam lift would be 0.87 multiplied
    by 0.665". That would be 0.579" of valve lift. That will
    put you right about where you need to be with valve
    lift versus cylinder head flow as I have specified above.

    Without using something like one of those Comp Cams
    that opens and shuts the valve like a 'Hammer', get
    as much 'Area' under the curve as you can.

    If it's okay with your engine builder, I can put you in
    touch with someone who can do that for you.

    Faster 'Flank' and opening rate and, more area under the curve
    without acting like a hammer.

    Be careful with that 12.0:1 static compression ratio.

    Make sure the intake valve closing point is 'Dead On'
    and the fuel is specified correctly. Also, make sure
    the 'Quench Gap' is sufficient.

    I might 'Reconsider' moving up to that high of a static Cr.
    Just might not be worth it. . . .

    If you want to contact me again to discuss this engine,
    as we did the previous one, just let me know.

    You build expensive engines and I myself would like
    to see the next one last my friend.

    Take care George!

    Cheers,
    Bruce
    Last edited by Rubber Duck; 09-03-2019 at 10:07 PM.
    adam112 and Blades1_99 like this.
    Calculating the valve curtain area
The following equation mathematically defines the available flow area for any given valve diameter and lift value:
Area = valve diameter x 0.98 x 3.14 x valve lift
Where 3.14 = pi (π)
For a typical 2.02-inch intake valve at .500-inch lift, it calculates as follows:
Area = 2.02 x 0.98 x 3.14 x 0.500 = 3.107 square[Contact UsArchiveTop

  3. #3
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    ouch!
    2012 CTS-V Sedan 6MT - Triple black - 2.5" upper pulley, Magnaflow exhaust, Airaid Intake, Fluidyne HX

    2014 Porsche 911 PDK - Dark Blue Metallic over 2 tone black/tan leather

    2001 Honda S2000 - Grand Prix White over Red - 9000 rpm yo!

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    death by boost... Sounds like the new block is going to be a beast!! Quick question... Why is an I beam rod better than an H? Just curious for my own knowledge...
    My new engine is being built I beam rods also...
    Metco 2.4 upper/ Green Supercharger Belt/ TSP 2inch headers to full 3 inch with X-pipe to stock mufflers/ Jabsco intercooler pump
    160* thermostat/ ID1050cc injectors/ BRF7 spark plugs/ Formato block off plates/ Weapon X underhood expansion tank/ AirRaid/
    Formato Ported stock LSA throttlebody/ Guarantee revoked tune


    602 whp/ 608 ft-lbs of torque on pump. A little more on the corn...lol

  6. #5
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    Quote Originally Posted by NOLAG05 View Post
    death by boost... Sounds like the new block is going to be a beast!! Quick question... Why is an I beam rod better than an H? Just curious for my own knowledge...
    My new engine is being built I beam rods also...
    You mean you don't remember the 'Great Con Rod' debate
    between Matt / GP Tuning and I...lol

    I will find the info and post it.

    But that is exactly how an H-Beam con rod breaks
    most of the time.

    The only place the H-Beam is stronger, is up around
    the wrist pin area.

    If George had just completed adding more ignition advance, and
    I am correct in surmising the 'Quench and Squish Velocity'
    issues, then this 'Might?' have caused the con rod to break.

    More later when I have time. . . .
    random84 likes this.
    Calculating the valve curtain area
The following equation mathematically defines the available flow area for any given valve diameter and lift value:
Area = valve diameter x 0.98 x 3.14 x valve lift
Where 3.14 = pi (π)
For a typical 2.02-inch intake valve at .500-inch lift, it calculates as follows:
Area = 2.02 x 0.98 x 3.14 x 0.500 = 3.107 square[Contact UsArchiveTop

  7. #6
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    Quote Originally Posted by Rubber Duck View Post
    You mean you don't remember the 'Great Con Rod' debate
    between Matt / GP Tuning and I...lol

    I will find the info and post it.

    But that is exactly how an H-Beam con rod breaks
    most of the time.

    The only place the H-Beam is stronger, is up around
    the wrist pin area.

    If George had just completed adding more ignition advance, and
    I am correct in surmising the 'Quench and Squish Velocity'
    issues, then this 'Might?' have caused the con rod to break.

    More later when I have time. . . .

    I have a broken Ultra I beam that met an unfortunate fate in an LSX 388.... Nothing is immune to failure
    Last edited by Lt1z; 09-04-2019 at 09:58 AM.

  8. #7
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    Quote Originally Posted by Lt1z View Post
    I have a broken Ultra I beam that met an unfortunate fate in an LSX 388.... Nothing is immune to failure
    Ooooohhhhh Noooooo, not again..lol

    Let's just say my experience building many, many engines
    has shown me that all con rods break, but the propensity
    for H-Beams to break, similar to / as this one did is more
    prevalent with H-Beams then with I-Beams.

    If you differ with the above, then I will simply say
    that you are entitled to your opinion.

    ------------------------------------------------

    In my career I owned an Production Engine Facility
    whereby we had 35 employees. We build 8 - 13 engines
    per day. I oversaw all machine work and assembly.

    In our performance division we built about 3-Performance
    Engines a month. On top of that we maintained several
    engines for our own cars.

    The production engine business extended for over ten years.
    The performance engine business extended for about 25-Years.

    Total it all up and that is thousands of engines. . . .

    The 'Propensity' for H-Beam Rods to beak (as did this one,
    and please look at the picture to see what I mean) is far
    higher than an I-Beam. . . . Of the same quality material.

    In other words; I-Beams won't break in that manner, when
    the con rod is made of the same material, and the cylinder
    pressure on top of the piston is the same, when the crankshaft
    and piston movement, given in degrees, is exactly at the same
    position.


    I went through this with engineers many years, ago who
    ran cyclic tests on con rods, after I lost an engine when
    a salesman sold me on H-Beam rods.

    So, my experience tells me that all con rods can break.

    But H-Beams break in a different manner then
    do I-Beams. Also, where an I-Beam will bend, the
    H-Beam might break. The only place on the con
    rod that is stronger on an H-Beam, is up at the top
    of the rod (small end) where the wrist pin is held.

    Respectfully,
    The Duck
    subaru335i likes this.
    Calculating the valve curtain area
The following equation mathematically defines the available flow area for any given valve diameter and lift value:
Area = valve diameter x 0.98 x 3.14 x valve lift
Where 3.14 = pi (π)
For a typical 2.02-inch intake valve at .500-inch lift, it calculates as follows:
Area = 2.02 x 0.98 x 3.14 x 0.500 = 3.107 square[Contact UsArchiveTop

  9. #8
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    Quote Originally Posted by Rubber Duck View Post
    Ooooohhhhh Noooooo, not again..lol

    Let's just say my experience building many, many engines
    has shown me that all con rods break,
    Je suis d'accord

  10. #9
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    In for knowledge of two of the guys I respect the most.
    NOLAG05 and Rubber Duck like this.
    "Pearl" is a 2011, V Coupe, A6, Recaros, Skyview.

    Mods: Airaid - Red filter, Side Swipe, Mamo LS7 Ported TB, ZL1 lid, Fasterproms underhood tank, BMR Catch Can, ....

  11. #10
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    I never really thought this would happen again, but here we go. . . .
    -Some posts from sometime back regarding this subject-

    A connecting rod works in two domains:

    1) Tension Loading
    2) Compression Loading

    A connecting rod’s max tension loads are determined by the mass of the parts involved, the rod length, the stroke length, and the max rpm.. . . Nothing More!

    So then;
    the max tension loads will never change, no matter what ‘Power Adder’ you add to your engine.

    That max tension loading occurs at TDC on the exhaust stroke.
    This has nothing what so ever to do with the amount of HP being made.

    On the other hand; the connecting rods max compression loads are determined by
    the amount of HP being made. It’s a simple matter; the higher the HP, the higher
    the compression loading on the connecting rod will be.

    So if the HP is increased, the compression loading will also be increased on the connecting rod.

    The I-Beam rod design has about twice the strength in compression,
    making the I-Beam Connecting Rod the best choice.


    The above describes why an I-Beam will usually bend
    when an H-Beam will break. . . . .

    Cheers,
    The Duck

    -------------------------------------------------------------------

    -and a later post on this subject-

    By the way; the last I heard; it is mandatory for an F1 Engine to use I-Beam rods!

    HP is what determines the compression loads on a rod and,
    I-Beams support those loads better than do H-Beams.

    Consider an H beam rod under a bending moment.
    There are just 2 very skinny flanges that have to bear the weight.

    There is not much skin on the surface of those 2 little skinny flanges
    to reinforce the con rod in compression.

    That is why an H beam is not used in many non automotive applications.


    ----------------------------------------------------------------

    I decided to perform some additional research after your last post.

    Consider the following as well;
    The lighter, stronger and more efficient I-beam design is why Auto OEM, piston aircraft, large ship, trains,
    and other industrial engines, as well as aircraft, spacecraft, and ship structural frames and of course,
    bridges and large buildings, all use I-beams.

    "If the H-Beam is better, then why haven't they been used in the above applications"?

    -additional food for thought-
    The highest cylinder pressures are just after top dead center. The piston has very little leverage at that point so the
    connecting rod must take the load. The load increases as HP goes up! <= This partially describes what happened to George

    By the time the piston has the greatest leverage ( 75 deg or so ATDC ), the cylinder pressure has been greatly reduced.

    So as you can now see; the rod sees its highest 'Compression Load' right after TDC, while at peak torque rpm, not peak HP rpm.

    Highest 'Tension Load' is 'Always' at the highest rpm at TDC on the exhaust stroke.

    Now, go back up to where I cite all the engineering facts regarding various industries
    that specify and use I-Beams.

    The
    Duck

    -------------------------------------------------------------

    And for those interested I also found this in my files from the past:

    Some General Guidelines regarding Connecting Rod Lengths / Ratios:

    1.40-1.60:1 is short
    1.65-1.80 is nice for most applications
    1.85-2.1+ is good for large bore short stroke, high rpm situations

    --------------------------------------------

    But as you increase the Rod Ratio, the Piston Dwell Periods at TDC
    and BDC are not changed 'Symmetrically', but Asymmetrically.

    That is:
    As Con Rod Ratios 'Go Up' the Dwell Period of the piston is not 'Increased'
    the same amount at TDC, as it is 'Increased' at BDC.

    One now can easily imagine how the Inertia Effect of a very dense
    Mass Charge would like an 'Optimum' length Con Rod and an intake valve
    that closes just a 'Little' late..

    --------------------------------------------

    In general, regarding Con Rod Lengths and Ratios, it goes like this:

    Rod Ratio Relationships;
    Short Rod is slower at BDC range and faster at TDC range.
    Long Rod is faster at BDC range and slower at TDC range.

    On the Intake Stroke; the Long Rod will draw harder on cylinder head from 90* ATDC to BDC.

    On the Intake Stroke; Short rod spends less time near TDC and will suck harder on the cylinder head from
    10* ATDC to 90* ATDC the early part of the stroke.

    But will not suck as hard from 90* ATDC to BDC as a long rod.

    --------------------------------------------

    Looking at the entire process;
    1) Generate Sufficient Flow through the heads
    2) Control Pressure Recovery in Cylinder
    3) Maximize Flow at BDC via Inertia Filling.

    Respecftully,
    The Duck
    Last edited by Rubber Duck; 09-04-2019 at 12:04 PM.
    Blades1_99 likes this.
    Calculating the valve curtain area
The following equation mathematically defines the available flow area for any given valve diameter and lift value:
Area = valve diameter x 0.98 x 3.14 x valve lift
Where 3.14 = pi (π)
For a typical 2.02-inch intake valve at .500-inch lift, it calculates as follows:
Area = 2.02 x 0.98 x 3.14 x 0.500 = 3.107 square[Contact UsArchiveTop

  12. #11
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    Quote Originally Posted by Lt1z View Post
    Je suis d'accord
    Does that go with 'aus jus' at a dinner with wine..lol
    subaru335i and Lt1z like this.
    Calculating the valve curtain area
The following equation mathematically defines the available flow area for any given valve diameter and lift value:
Area = valve diameter x 0.98 x 3.14 x valve lift
Where 3.14 = pi (π)
For a typical 2.02-inch intake valve at .500-inch lift, it calculates as follows:
Area = 2.02 x 0.98 x 3.14 x 0.500 = 3.107 square[Contact UsArchiveTop

  13. #12
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    Just my opinion from what I have seen in George's video,
    but here is another component (most probably) that can
    contribute to such issues.

    Also please highlight the info where I discussed rod angle
    in degrees at TDC, whereby the con rod is almost vertical
    when the charge is ignited.

    Fast burn cylinder heads, such as the LS-Engine series
    are in fact fast burn heads.


    ---------------------------------------------------------

    Here we go with another post I made sometime back:
    Some general info and considerations regarding quench & squish:

    Squish velocity is determined by three factors:
    piston to head clearance, squish area ratio _Piston area / _Squish area),
    and piston speed. All three must be considered along with ignition timing.

    Squish velocity is the speed at which air is displaced from between the piston
    and head surface as the piston approaches TDC.

    So again; it is the result of three factors: clearance, area and piston speed.

    Inlet air temperature and mixture also play a role.

    Considering the above, only clearance and squish ratio are fixed by design.

    The other variables can be changed, or will
    change as a result of engine operating conditions.

    An engine with low squish velocity will not complete the combustion
    process in the allotted time during high engine speed operation.

    An engine with excessively high squish velocity will burn too rapidly,
    causing combustion pressure rise at or before TDC. <= This also
    happens or is exaggerated when using Nitrous.

    ---------------------------------------------------------------

    Excessively high squish velocity can move the combustion pressure
    curve too close to TDC, causing a loss of power and possible pre-ignition.

    Some believe the above can happen if the 'squish clearance'
    is set for less than 0.050" on an NA Engine.

    Some also believe that anything less than 0.060"
    of squish clearance will cause 'pumping losses'.

    Others believe that anything over 0.035" of
    squish clearance will cause the engine to
    be down on power.

    And some state that the 'minimum' squish clearance
    should be set relative to the bore size.

    They then calculate the required squish clearance stating
    that the squish clearance should amount to 0.005"
    of clearance per inch of bore diameter.

    That would only be about 0.020" for a 4" bore.
    The above info came from MIT years back!

    -generally speaking-
    When the gap / squish clearance is less than 0.050"
    the flame is quenched and end gasses are left over.

    When the gap / squish clearance is over 0.050"
    the flame front can enter, not be quenched
    and those gases are burnt. <= Flame front or
    propagation here is important!

    The downside to using a squish clearance of
    somewhere between 0.050" to maybe 0.100"
    is the following. . . . .

    =>If the flame speed is to low, this allows for the combustion
    end gases to heat up to auto-ignition temperatures causing
    detonation. End gases aid in causing auto / self detonation.

    This is why some (high FI pressure ratios & Nitrous applications)
    convert the wedge head (hard head) to a soft head, by blowing
    out the chamber, thereby ostensibly converting it to an open chamber.

    And conversely;
    As I stated above; excessively high squish velocity can
    move the combustion pressure curve too close to TDC,
    causing a loss of power and possible pre-ignition.


    The above once again ties in with the 'almost' vertical con rod.

    ---------------------------------------------------------------

    Now, let's look a look at this from another perspective that might help us understand;

    Some years back we found that as we increased the percent
    of 'volumetric efficiency' within the higher engine rpm range,
    we could not run the fuel that NHRA demanded we use.

    We were running a static compression ratio of 15.2:1.
    But because the engine was so efficient, the 'trapped
    compression' ratio exceeded ~17.2:1.

    This is because the trapped compression, or as some
    call it; the dynamic compression ratio is increased
    in relationship to the amount of fuel the engine
    was pulling in. Fuel takes up area and this then
    reduces the area of the combustion chamber
    when the piston is at TDC, thereby increasing
    the 'trapped compression'.

    So what do you suppose is happening with a
    Supercharged Engine. . . . .

    The required 'squish clearance' can be calculated.

    I begin with the 0.035" of 'squish gap',which most
    use in performance NA engines.

    Then you simply factor the above via a simple
    mathematical calculation utilizing a portion of
    the density ratio.

    Since you have contacted Matt (which I was going to recommend)
    then the two of you can determine what will fill your needs together.

    Happy New Year!
    Last edited by Rubber Duck; 09-04-2019 at 12:29 PM.
    Calculating the valve curtain area
The following equation mathematically defines the available flow area for any given valve diameter and lift value:
Area = valve diameter x 0.98 x 3.14 x valve lift
Where 3.14 = pi (π)
For a typical 2.02-inch intake valve at .500-inch lift, it calculates as follows:
Area = 2.02 x 0.98 x 3.14 x 0.500 = 3.107 square[Contact UsArchiveTop

  14. #13
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    Quote Originally Posted by Rubber Duck View Post
    I never really thought this would happen again, but here we go. . . .
    -Some posts from sometime back regarding this subject-

    A connecting rod works in two domains:

    1) Tension Loading
    2) Compression Loading

    A connecting rod’s max tension loads are determined by the mass of the parts involved, the rod length, the stroke length, and the max rpm.. . . Nothing More!

    So then;
    the max tension loads will never change, no matter what ‘Power Adder’ you add to your engine.

    That max tension loading occurs at TDC on the exhaust stroke.
    This has nothing what so ever to do with the amount of HP being made.
    ACKTUALLY!!

    Consider a turbo motor that makes 40 psi of backpressure. Cylinder pressure never drops to zero while the exhaust valve is open. 40 psi of backpressure on a 4" bore is 502 lbf.
    subaru335i likes this.
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    The only real argument I have heard for H beams before (vs I beam) is lower cost and lighter rotating mass.

    Lighter mass seems like it would only really make a big difference in high rpm applications but if you look at the Honda S2000 F20C OEM rod it is an I beam...and it ties the Ferrari 458 for highest redline in a production engine!

    I have definitely seen a lot of broken H beams and bent I beams (and more rarely broken I beams but usually doing something crazy).
    Rubber Duck likes this.
    2012 CTS-V Sedan 6MT - Triple black - 2.5" upper pulley, Magnaflow exhaust, Airaid Intake, Fluidyne HX

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    2001 Honda S2000 - Grand Prix White over Red - 9000 rpm yo!

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    Quote Originally Posted by subaru335i View Post
    The only real argument I have heard for H beams before (vs I beam) is lower cost and lighter rotating mass.

    Lighter mass seems like it would only really make a big difference in high rpm applications but if you look at the Honda S2000 F20C OEM rod it is an I beam...and it ties the Ferrari 458 for highest redline in a production engine!

    I have definitely seen a lot of broken H beams and bent I beams (and more rarely broken I beams but usually doing something crazy)
    .
    You got to be 'Crazy Nuts' to do what we all do with our rides..
    Calculating the valve curtain area
The following equation mathematically defines the available flow area for any given valve diameter and lift value:
Area = valve diameter x 0.98 x 3.14 x valve lift
Where 3.14 = pi (π)
For a typical 2.02-inch intake valve at .500-inch lift, it calculates as follows:
Area = 2.02 x 0.98 x 3.14 x 0.500 = 3.107 square[Contact UsArchiveTop

  17. #16
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    Quote Originally Posted by MeanMike View Post
    ACKTUALLY!!

    Consider a turbo motor that makes 40 psi of backpressure. Cylinder pressure never drops to zero while the exhaust valve is open. 40 psi of backpressure on a 4" bore is 502 lbf.
    Yes, but. . .
    Does the back-pressure cancel out all, or just some of the forces involved.

    Here is the piston motion and G-Forces for a 376 cid
    engine spun to 7,000 rpm's.

    Just for 'Kicks..lol
    How would you imagine the G-Forces would change?

    ------- Piston Motion Data -------
    Average Piston Speed. . . . . . . . . . (FPM)= 4225.67 in Feet Per Minute
    Maximum Piston Speed. . . . . . . . . (FPM)= 6925.896 occurs at 74.65985 Degrees ATDC
    Piston Depth at 74.660 degree . . . ATDC= 1.5873 inches Cylinder Volume= 337.6 CC
    Maximum TDC Rod Tension. . . . . GForce= 3268.7850 G's
    Maximum BDC Rod Compression. . GForce= 1772.1930 G's
    Calculating the valve curtain area
The following equation mathematically defines the available flow area for any given valve diameter and lift value:
Area = valve diameter x 0.98 x 3.14 x valve lift
Where 3.14 = pi (π)
For a typical 2.02-inch intake valve at .500-inch lift, it calculates as follows:
Area = 2.02 x 0.98 x 3.14 x 0.500 = 3.107 square[Contact UsArchiveTop

  18. #17
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    You said the power adder didn't matter. But it does change with a turbo with back pressure. I think this is why you see such great success with turbo's stock bottom end LS motors. That backpressure keeps the rod from seeing the same tension loads it would see in a similar NA or blown motor.

    I’d like to see the numbers behind those rod tension gforce calculations. G is a unit of acceleration. 32.2ft/sec^2. To get force on the rod F=MA. Mass would be the piston, pin, rings and small end rod weight. Typically a little less than 2 lbs. F=2*(3268.75*32.2)=210,000lbf. Two 7/16 arp 2000 rod bolts are only good for 45,000lbf. total. That acceleration seems off to me, but I make mistakes in math.


    I made a piston speed and acceleration spreadsheet back in my IC engines class in college. I’ll see if I can dig it up.

    Edit: Maybe it's just supposed to be 3268ft/s^2 and the "G" is redundant. So F=2*(3268)=6536lb. In that case, 500lbf counteracting that makes it only 6000lb tension on the rod, an 8% decrease in load.
    Last edited by MeanMike; 09-04-2019 at 04:17 PM.
    Rubber Duck and subaru335i like this.
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  19. #18
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    What 1/4 mile numbers did you get prior to it letting go?

    I just don’t hear of any results from the TT builds.


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  20. #19
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    Something theory mumbo jumbo to add to the Rod discussion.

    Parts like rods, wrist pins, cranks can break from single time overloading or from cyclical loading over time. With the cyclical loading, you get a decrease in life depending on the load. It's typically shown by and SN curve (stress/force vs number of cycles). You can google one, but basically it says that when you cyclically load something above ~50% of it's tensile strength there is a finite life. The closer you get to the tensile strength the shorter the life. Under ~50% it could theoretically go forever. That ~50% of tensile strength is the fatigue life and varies based on material.

    The physical way this happens is by crack growth. Some imperfection in or on the part starts a crack and it grows with each cycle. This is why we shot peen rods or check used cranks for cracks. So, you don't have to go above tensile strength to break a rod. But it does need to see significant loading and lots of cycles to break.

    Why this matters on the turbo setup, is that difference between compressive and tensile stress is lower due to the backpressure keeping some compressive load on the rod. The average between the two is the number you use in the sn curve. Since it's lower, you get a logarithmically longer life.

    We are all making wild guesses based on limited info here. CUIN9SEC has the whole story in front of him, we just get limited pictures from the video. It could have overheated the rings drug the piston pulling the wrist pin out of the piston, the pin could have seized in the piston put some bending load on it. There's lots of possiblities for failure besides just compressive and tensile loading. Failure analysis is hard because it was turning some rpm when it came apart and secondary damage probably hid most everything.

    That's all the nerding I can handle for the day.
    09 TG Sedan A6, 2.55/9.17, ARH 1 7/8, LT1Z 2.5, GMPP CNC LS3, Jokerz chaos 102, NW102, Trunk tank/ EMP, C&R HX, Airaid, DSX pump and flex sensor, ID1050x’s. 1.42, [email protected]

  21. #20
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    Cts-v 388 blow up video

    So if the headers are touching the plug wires ...


    Sent from my iPhone using Tapatalk
    Blades1_99 likes this.
    Metco 2.4 upper/ Green Supercharger Belt/ TSP 2inch headers to full 3 inch with X-pipe to stock mufflers/ Jabsco intercooler pump
    160* thermostat/ ID1050cc injectors/ BRF7 spark plugs/ Formato block off plates/ Weapon X underhood expansion tank/ AirRaid/
    Formato Ported stock LSA throttlebody/ Guarantee revoked tune


    602 whp/ 608 ft-lbs of torque on pump. A little more on the corn...lol

  22. #21
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    Quote Originally Posted by MeanMike View Post
    You said the power adder didn't matter. But it does change with a turbo with back pressure. I think this is why you see such great success with turbo's stock bottom end LS motors. That backpressure keeps the rod from seeing the same tension loads it would see in a similar NA or blown motor.

    I’d like to see the numbers behind those rod tension gforce calculations. G is a unit of acceleration. 32.2ft/sec^2. To get force on the rod F=MA. Mass would be the piston, pin, rings and small end rod weight. Typically a little less than 2 lbs. F=2*(3268.75*32.2)=210,000lbf. Two 7/16 arp 2000 rod bolts are only good for 45,000lbf. total. That acceleration seems off to me, but I make mistakes in math.


    I made a piston speed and acceleration spreadsheet back in my IC engines class in college. I’ll see if I can dig it up.

    Edit: Maybe it's just supposed to be 3268ft/s^2 and the "G" is redundant. So F=2*(3268)=6536lb. In that case, 500lbf counteracting that makes it only 6000lb tension on the rod, an 8% decrease in load.
    I would say your pretty close..

    ---------------------------------------

    Again, just for 'Kicks'. . .
    Here is a 500 cid NHRA Pro Stock Engine turning 11,300 rpm's

    ------- Piston Motion Data -------
    Average Piston Speed. . . . . . . . . . . . (FPM)= 6638.75 in Feet Per Minute
    Maximum Piston Speed. . . . . . . . . .(FPM)= 10850.335 occurs at 75.09814 Degrees ATDC
    Piston Depth at 75.098 degree . . . . ATDC= 1.5498 inches Cylinder Volume= 450.0 CC
    Maximum TDC Rod Tension. . . . GForce= 8224.2234 G's
    Maximum BDC Rod Compression. . GForce= 4560.3513 G's

    See that 'Peak' piston speed of 10,850.335 fpm.
    That's how you make power!

    The ability for an engine to supply the piston cfm requirements
    at either the 'Average'' value, or the 'Peak' value, is the
    difference between a new 'Cadillac' and 'Steak Knives'...lol

    If your heads can flow sufficiently to meet the engines demand
    at 'Peak Piston Speed' and your spinning the engine as fast or
    faster then your competitor, then your competitor is going
    to get the 'Steak Knives'..

    Our engines don't come close to meeting those demands,
    even with an Eaton TVS Blower on it.

    The Pro Stock engine is filling the cylinders at about 152% in an NA configuration.
    Most of us are only filling the cylinders to maybe 100% using the TVS Eaton Blower.

    Some a little more, and some a little less. . . .

    Cheers
    Last edited by Rubber Duck; 09-05-2019 at 06:43 AM.
    Blades1_99 likes this.
    Calculating the valve curtain area
The following equation mathematically defines the available flow area for any given valve diameter and lift value:
Area = valve diameter x 0.98 x 3.14 x valve lift
Where 3.14 = pi (π)
For a typical 2.02-inch intake valve at .500-inch lift, it calculates as follows:
Area = 2.02 x 0.98 x 3.14 x 0.500 = 3.107 square[Contact UsArchiveTop

  23. #22
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    Quote Originally Posted by MeanMike View Post
    Something theory mumbo jumbo to add to the Rod discussion.

    Parts like rods, wrist pins, cranks can break from single time overloading or from cyclical loading over time. With the cyclical loading, you get a decrease in life depending on the load. It's typically shown by and SN curve (stress/force vs number of cycles). You can google one, but basically it says that when you cyclically load something above ~50% of it's tensile strength there is a finite life. The closer you get to the tensile strength the shorter the life. Under ~50% it could theoretically go forever. That ~50% of tensile strength is the fatigue life and varies based on material.

    The physical way this happens is by crack growth. Some imperfection in or on the part starts a crack and it grows with each cycle. This is why we shot peen rods or check used cranks for cracks. So, you don't have to go above tensile strength to break a rod. But it does need to see significant loading and lots of cycles to break.

    Why this matters on the turbo setup, is that difference between compressive and tensile stress is lower due to the backpressure keeping some compressive load on the rod. The average between the two is the number you use in the sn curve. Since it's lower, you get a logarithmically longer life.

    We are all making wild guesses based on limited info here. CUIN9SEC has the whole story in front of him, we just get limited pictures from the video. It could have overheated the rings drug the piston pulling the wrist pin out of the piston, the pin could have seized in the piston put some bending load on it. There's lots of possiblities for failure besides just compressive and tensile loading. Failure analysis is hard because it was turning some rpm when it came apart and secondary damage probably hid most everything.

    That's all the nerding I can handle for the day.
    This forum in my opinion Mike, is a good forum, with good people.
    It is an elevated 'Hobbyist' forum, but it is not Speed Talk.

    And thank goodness it is not 'Yellow Bullet', where all everyone does is
    argue with each other.

    Debating about what broke a motor, or what makes an engine
    make more HP or Torque, takes place on Speed Talk all the time.

    Speed Talk is the most technically advanced forum I know of.

    I don't see any difference between what we are doing within this thread,
    versus many threads I have been involved with on Speed Talk.

    So define a Nerd for me Mike.
    When they discuss what 'Might' have broke and engine on Speed Talk, are they Nerd's also?
    Last edited by Rubber Duck; 09-04-2019 at 05:35 PM.
    subaru335i likes this.
    Calculating the valve curtain area
The following equation mathematically defines the available flow area for any given valve diameter and lift value:
Area = valve diameter x 0.98 x 3.14 x valve lift
Where 3.14 = pi (π)
For a typical 2.02-inch intake valve at .500-inch lift, it calculates as follows:
Area = 2.02 x 0.98 x 3.14 x 0.500 = 3.107 square[Contact UsArchiveTop

  24. #23
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    If my TI-85 calculator and the words stress, strain, fatigue or anything with more than 3 syllables gets typed, it’s nerdy. That’s not a bad thing. I enjoy it from time to time. But it gives me flashbacks to cramming for my PE exam.
    09 TG Sedan A6, 2.55/9.17, ARH 1 7/8, LT1Z 2.5, GMPP CNC LS3, Jokerz chaos 102, NW102, Trunk tank/ EMP, C&R HX, Airaid, DSX pump and flex sensor, ID1050x’s. 1.42, [email protected]

  25. #24
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    Quote Originally Posted by MeanMike View Post
    If my TI-85 calculator and the words stress, strain, fatigue or anything with more than 3 syllables gets typed, it’s nerdy. That’s not a bad thing. I enjoy it from time to time. But it gives me flashbacks to cramming for my PE exam.
    Personally I think you do a good job with your TI-85 calculator..
    And yes, I make mistakes with my HP-44 calculators also..
    Calculating the valve curtain area
The following equation mathematically defines the available flow area for any given valve diameter and lift value:
Area = valve diameter x 0.98 x 3.14 x valve lift
Where 3.14 = pi (π)
For a typical 2.02-inch intake valve at .500-inch lift, it calculates as follows:
Area = 2.02 x 0.98 x 3.14 x 0.500 = 3.107 square[Contact UsArchiveTop

  26. #25
    Super Moderator
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    Oxford Michigan.... Detroit suburbs
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    Cts-v 388 blow up video

    Still rocking my Ti 81

    Ti85 is for the younger crowd lol

    Could never do the RPN HP’s


    Sent from my iPhone using Tapatalk
    Rubber Duck likes this.
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  27. #26
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    Quote Originally Posted by larry arizona View Post
    Still rocking my Ti 81

    Ti85 is for the younger crowd lol

    Could never do the RPN HP’s


    Sent from my iPhone using Tapatalk
    I like RPN, as it allows one to perform a calculation, then stack it,
    complete the second calculation and move ahead to add multiply
    divide etc., without having to make anymore inputs to the
    calculator.

    But it is embarrassing to watch me use my calculator in my phone..
    Calculating the valve curtain area
The following equation mathematically defines the available flow area for any given valve diameter and lift value:
Area = valve diameter x 0.98 x 3.14 x valve lift
Where 3.14 = pi (π)
For a typical 2.02-inch intake valve at .500-inch lift, it calculates as follows:
Area = 2.02 x 0.98 x 3.14 x 0.500 = 3.107 square[Contact UsArchiveTop

  28. #27
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    Ti-89 got rode hard at the University
    Build Thread for the Madallac

    Open and Shut - A Tranny Story (TR6060 Teardown and Rebuild)

    JRi Coilovers

    ’09 Sedan Black on Black Recaros 6MT
    Forged HED LSA 10:1 GP 2.5 Ported LSA Heads/TVS1900 Johnson 2110s 2.70/9.55 Pulleys D3 Intake Lid Spacer SW 2”/Catless/Magnaflow Resonators/Corsa Spt DIY Flex Setup ID1300Xs DW300Cs + Walbro 297 Map Ref Aux
    Low Mount D3 HX and Pump -10 Setrab Oil Cooler Diff Cooler Lowered on JRIs Subframe Reinforcement Front and Rear D3 Sway Bars Core Shifter Mantic Twin Disc Clutch Swapped/Widened Sedan Wheels

  29. #28
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    I snapped a Manley pro billet I beam rod last year in my lsx. Surprisingly, it just needed to be bored .030 to clean it up.
    Manny

    2009 Black Raven CTS-V 6MT


    388ci LSX in progress
    Twin Precision 6266s
    ID1700s
    FORE Triple TI267s
    RPS Triple Carbon
    1155rwhp/1122rwtq @20psi (E60) on old LSA

  30. #29
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    Quote Originally Posted by adam112 View Post
    Ti-89 got rode hard at the University
    Oh really? You rode her real hard I bet.

    Sent from my SM-G965U using Tapatalk

  31. #30
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    Quote Originally Posted by random84 View Post
    Oh really? You rode her real hard I bet.

    Sent from my SM-G965U using Tapatalk
    If she aint integrating, neither are we, ya feel me?
    NOLAG05 likes this.
    Build Thread for the Madallac

    Open and Shut - A Tranny Story (TR6060 Teardown and Rebuild)

    JRi Coilovers

    ’09 Sedan Black on Black Recaros 6MT
    Forged HED LSA 10:1 GP 2.5 Ported LSA Heads/TVS1900 Johnson 2110s 2.70/9.55 Pulleys D3 Intake Lid Spacer SW 2”/Catless/Magnaflow Resonators/Corsa Spt DIY Flex Setup ID1300Xs DW300Cs + Walbro 297 Map Ref Aux
    Low Mount D3 HX and Pump -10 Setrab Oil Cooler Diff Cooler Lowered on JRIs Subframe Reinforcement Front and Rear D3 Sway Bars Core Shifter Mantic Twin Disc Clutch Swapped/Widened Sedan Wheels


 
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