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  1. #31
    Join Date
    Sep 2006
    Location
    Calgary, Alberta
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    Quote Originally Posted by richierevs View Post
    Thanks Simon... I remember when I was having my engine ported, polished, and balanced that obstructive air flow was an important consideration... I can't seen to find the test results (it's been a while) but I tested two different 90 degree elbows: a curved elbow, and a cobra-head elbow. As I remember the cobra-head produced less turbulance at the turn, based on its design... I'm pissed that I can't find the data sheet on the comparison test... Anyway, I've been using the cobra-head elbow ever since.
    Yes, different and important issue. As opposed to the 5.7 / 6.1 / Eagle intakes, the Apache has an angled entry to address the issues you're referring to. Folks have probably read me talking about the fact air has mass. When air encounters a change in direction like a bend, just like your car on a corner, it wants to go straight instead of turn. Its difficult to put into enough convincing words - just how much drag and turbulence this creates within the intake tract.

    The same problem occurs within the exhaust system. Non-mandrel bends make the problem magnitudes worse by introducing even more drag due to changes in relative pressure as the exhaust gas encounters a change in cross sectional area.

    That air mass...if you can imagine air being pulled or pushed into an intake runner that has zero blending, through 360 degrees around the opening. As engine rpm increases that air volume begins to run into one another - just like they do within a 90 degree bend on a 6.1. The end result is the air itself begins to block the aperture right at entry.

    I'm surprised to see the lack of well-known and proven effective aero / fluid dynamics, the very things that make something function significantly better than without...being flogged at $800+USD.


    Edit: I mentioned this previously, but it bears repeating. That air impingement has another negative effect; pressure deltas, in this case an increase results in higher intake charge temperature at the valves (well past the IAT sensor).
    Last edited by Hemissary; 08-13-2019 at 04:57 PM. Reason: Added thermal issue...
    2005 Magnum RT---Viper Venom Red----440ci Aluminum block----Short Runner Valve Intake--410mm BAER 6S Monoblock Extreme--Eibach Multi-Pro 2

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  2. #32
    Join Date
    Mar 2008
    Location
    Stamford, CT
    Posts
    4,086
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    Quote Originally Posted by Hemissary View Post
    Yes, different and important issue. As opposed to the 5.7 / 6.1 / Eagle intakes, the Apache has an angled entry to address the issues you're referring to. Folks have probably read me talking about the fact air has mass. When air encounters a change in direction like a bend, just like your car on a corner, it wants to go straight instead of turn. Its difficult to put into enough convincing words - just how much drag and turbulence this creates within the intake tract.

    The same problem occurs within the exhaust system. Non-mandrel bends make the problem magnitudes worse by introducing even more drag due to changes in relative pressure as the exhaust gas encounters a change in cross sectional area.

    That air mass...if you can imagine air being pulled or pushed into an intake runner that has zero blending, through 360 degrees around the opening. As engine rpm increases that air volume begins to run into one another - just like they do within a 90 degree bend on a 6.1. The end result is the air itself begins to block the aperture right at entry.

    I'm surprised to see the lack of well-known and proven effective aero / fluid dynamics, the very things that make something function significantly better than without...being flogged at $800+USD.


    Edit: I mentioned this previously, but it bears repeating. That air impingement has another negative effect; pressure deltas, in this case an increase results in higher intake charge temperature at the valves (well past the IAT sensor).
    Agreed... And as one flow bottleneck is fixed, the flow problem moves to a different area...such is the nature of continuous improvement...

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