smart51
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| posted on 11/1/07 at 12:27 PM |
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Carb trumpets
I've just read an article about air inlet bellmouth geometry for IC engines (carbs or FI). It found that a simple round bell mouth increses
airflow by around 16% over a cut pipe and a properly shaped eliptical trumpet improves airflow by nearly 20%. That's the airlflow capacity of
the carb or throttle body, not the whole inlet tract. More air, if properly jetted / mapped = more power. The effect increases with the sequare of
RPM so at half max RPM you only get 1/4 of the increased flow.
Everyone with R1 engines and the rubber trumpet removed from the bell mouth boss take note, it might be worth having some 4mm radiused bosses made up.
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alanr
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| posted on 11/1/07 at 12:41 PM |
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and not just R1's - Blades could be improved as well
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DavidM
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| posted on 11/1/07 at 12:59 PM |
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See DIY Si post on this thread:
http://www.locostbuilders.co.uk/viewthread.php?tid=46508
David
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DIY Si
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| posted on 11/1/07 at 01:00 PM |
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Beat me to it, I was just looking for that. Scanned from one of the Vizard books by the way. Probably the mini one I think.
“Let your plans be dark and as impenetratable as night, and when you move, fall like a thunderbolt.”
Sun Tzu, The Art of War
My new blog: http://spritecave.blogspot.co.uk/
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smart51
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| posted on 11/1/07 at 02:56 PM |
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The comments on that link say that you must roll the edge of the flare over. The article I read compared a flare at 90° to the axis and a full bead.
They found no real difference at the optimal flare radius.
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