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Old 08-11-2009, 11:58 AM   #1
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No offense taken...

Quote:
Originally Posted by blue2000s
No offense to Pedro at all with the following description, I'd just like to help clear things up a bit.
... as a matter of fact I applaud and welcome these discussions, since they help to enlighten us all.

Your fluid dynamic model of the plenum's Tee is very impressive and most likely correct, if there was no throttle body and butterfly valve controlling the airflow.

Because we have a throttle body with a butterfly valve, the flow of air into the Tee does not come from the center of the air channel, but through two crescent moon-shaped opening on the sides of the air channel. These variable openings, whose area is dictated by the position of the accelerator pedal, create all sorts of turbulence within the Tee.

When I started with my experiments I took a tee and made a clear porthole on its top so that I could see what was happening inside. Inside the Tee I had attached small streamers (much like those on the sails of a sailboat) which allowed me to see the airflow through the Tee from idle to wide-open throttle.
I also ran other visual experiments which I will document shortly with a short video showing the improved performance of the airflow.

Happy Boxstering,
Pedro
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Old 08-11-2009, 12:20 PM   #2
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Quote:
Originally Posted by ppbon
... as a matter of fact I applaud and welcome these discussions, since they help to enlighten us all.

Your fluid dynamic model of the plenum's Tee is very impressive and most likely correct, if there was no throttle body and butterfly valve controlling the airflow.

Because we have a throttle body with a butterfly valve, the flow of air into the Tee does not come from the center of the air channel, but through two crescent moon-shaped opening on the sides of the air channel. These variable openings, whose area is dictated by the position of the accelerator pedal, create all sorts of turbulence within the Tee.

When I started with my experiments I took a tee and made a clear porthole on its top so that I could see what was happening inside. Inside the Tee I had attached small streamers (much like those on the sails of a sailboat) which allowed me to see the airflow through the Tee from idle to wide-open throttle.
I also ran other visual experiments which I will document shortly with a short video showing the improved performance of the airflow.

Happy Boxstering,
Pedro
The stagnation and separation will still be present, even with the throttle plate there.
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