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  1. #1
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    Join Date
    Jun 2014
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    Willow Park
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    11

    Intake Manifold - Porsche's "Cool" Trick


  2. #2
    Member
    Join Date
    Jul 2010
    Location
    Calgary
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    286
    Thanks for sharing that - very cool trick indeed that I never would have thought of in that application - that adiabatic cooling gives you free horsepower. There's likely some fine tuning of this so they can get port velocities correct and not lose low end power, but with variable vane turbos they have so much more operating range now that they can likely compensate.

    (says the guy with the carbed engine that still never runs right)

  3. #3
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    Join Date
    Jun 2014
    Location
    Willow Park
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    11
    Yes it is smart to use the expansion cooling (called Joule Thompson effect) on intake air and compensate the loss in pressure with turbo. There is another significant advantage with cooler air i.e. higher density, which means more mass per unit volume, which the presenter neglected to highlight. We can get more mass into the cylinder per suction stoke with cooler air. Even the "external combustion engines" i.e. gas turbines work better at lower ambient temperatures due to larger mass flow compared to hotter ambient. Same reason why aircraft engines love minus temperatures and snowy conditions (after de-icing of course) as it can achieve greater thrust, lift and elevation gain.


 

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