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Calculate Average CSA of Port | |
Wallace Racing
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Scientific Design of Exhaust & Intake Systems (Engineering and Performance)
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Internal Combustion Engine in Theory and Practice:
AndA. Graham Bell's Performance Tuning in Theory and Practice..
To Calculate the Minimum Cross Sectional Area (CSA) of the cylinder head port using Bore, Stroke and RPM of the engine.
The Bore and Stroke is in inches.
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Example: (Pontiac 461 CID) Bore - 4.181" Stroke - 4.25" RPM - 7000 RPM's Minimum CSA is 2.78 square inches A 461 CID engine would need a minimum 2.78 sq/in CSA at 7000 RPM. |
To Calculate the Average Cross Sectional Area (CSA) of the cylinder head port.
The length of the port is from the port mounting flange (like the intake manifold flange on head) to the valve seat plane, in inches.
The Port Volume is the cylinder head port volume for the port being tested, in cubic centimeters.
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Example: (461 CID) Port Length - 5.163 inches Port Volume - 235.2 CC's Average CSA is 2.78 square inches A 461 CID engine with a port volume of 235 cc's and 5.163 inches length port would have a average 2.78 sq/in CSA at 7000 RPM. |
To Calculate the Intake Port Volume of the cylinder head using the Minimnum Cross Sectional Area (MCSA).
The length of the port is from the port mounting flange (like the intake manifold flange on head) to the valve seat plane, in inches.
The Minimum Cross Sectional Area is in square inches.
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Example (461 CID):
For a 7000 rpm from a 461 cid, we need 2.78 in2 MIN CSA and using a port length of 5.163 inches, port volume of 235cc is needed. |