I am going to change my method for comparing to something more similar to a flow bench sucking 28" of water. Right now simulations are airflow required per car at 6000rpm(assuming perfect volumetric efficiency) and have atmospheric pressure at the inlet.
The two designs come from varius places, one if from a drawing which gives the radii as a function of the total diameter and the second is defined by the square root function with a 1/4" full radius added.
I found that the square root function could provide a 179.48Pa manifold pressure that the alternative design and that with carb modifications another 568.78Pa could be gained.
The carb modifications were:
Thinned spindle
Raised Piston
Knife edge on butterfly
Radii on bridge
The radii on the bridge seemed the most worthwhile modification as it reduced a majour pressure drop(turbulence) on the lower backside of the butterfly. Most likely the radii pulled the air back down to the bottom of the carb(Coanda-effect) vs the sharp edge allowing it to break away. This could hinder fuel atomization however.
