Stan are there guys using the coefficient of discharge for something other than the port window and valve size? I thought that was more for orifice’s?
I remember using the coefficient of discharge calculations to come up with orifice diameters back when we built our flow bench. I tried to use similar data to find optimum port window in the head. I don’t recall having any luck with that. My ME fluids class memories aren’t all that fresh anymore either.
We took one d port 16, and ported it with the expectation that it would be ruined, just seeing where the port volume would would kill low lift flows. It was a little hard to tell what the port volume end up being because they had lots of leaks. I kept welding and brazing, and reshaping the port, making it bigger and bigger. Totally went through the ceiling. I was expecting to find a place were the low lifts flows tanked. The .1” flowed went down some, everything at the higher lifts just kept going up. Maybe someone else’s flow bench would say something different, we were pretty surprised. IRC we were up around 320-330 cfm when we quit, it was getting difficult to find metal to grind out.
Rocky Rotella let me look at the port work from one of the ported 64s that Jim Hand had on his car when he clocked at 11.30 @117. Lol, the only thing I learned is I am not worthy. 11.30 @117 with pump gas, in a 4000 lbs and a flat tappet cam using a 166 cc port volume d port. Holy cow that was fast for that set up!
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