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beepbeep beepbeep is offline
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Join Date: Jun 2001
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Originally Posted by 911st View Post
I would not think of a 930 manifold as pipes or tubes. It really dose not have any runners.

It is more like a pressurized vessel with 6 holes in it. Under boost it is the size of the hole or nozzle that determines flow.
I respectfully disagree. Middle "holes" are much shorter than "holes" going to outer cylinders.

A gentlemen on another forum has made a boxy plenum for his Porsche 928 in order to boost it with compressor. The "boxy" plenum has straight walls and huge cavities. Dyno-tests with stock 928 plenum vs. boxy-plenum in N/A mode revealed huge differences:

This makes me believe that a rework of OEM 930 plenum (which is suboptimal due to packaging constraints) plays major role in how much power you can extract from engine.

I'm always stumbled by how much power turbo-converted 3.2 Carrera guys get on mild boost from their otherwise similar engines. Some of that can be explained by EFI usage but I believe a good portion of that comes from better plenum.
Thank you for your time,

Last edited by beepbeep; 05-09-2009 at 11:35 PM..
Old 05-09-2009, 11:31 PM
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