Hi David,
Great article, very informative.
I'm currently reworking a set of Word Products SBC 220cc intake runner heads for
maximum performance, drag race application. My question is about the width of the
exahust short turn, should I make the bottom of the turn as wide as possible to slow
the port speed in this area?
Quote:
Originally Posted by DavidVizard-GFN
Note how this port looks very much like a nozzle with a bend in it. In real life it acts, at high valve lift, in much the same way. With a 1.6 inch valve the flow at 0.750 lift is over 260 cfm. With an exhaust pipe added the peak flow exceeds 300 cfm. Remember this is a near idealized form. To get the best from a port that is more a production style with a lower updraft angle we have to make compromises and generate forms that encourage the gasses to flow more easily past the guide boss and round a bend. That’s where the flow bench comes into it’s own!
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