Here are the flow figures for the Fish. Testing was done at 10" H20 depression, 56% Relative Humidity, 30.18 Barometric Pressure, and at 76 deg Farenheight. Results were also converted to the 3" HG two BBl carb standard.
At full throttle, flow was 145.7 Scfm @ 10", or 294 Scfm @ 3"HG. This compares fairly well with a flow figure given on the Minispeed site of 150 Scfm for the 1 1/2" Reese Fish. The 38mm Mikuni roundslide carb flows 152.7 Scfm (308.4 @ 3"HG), so the Fish is doing quite well for a butterfly carb. Flow at 1/2 throttle was 52.2 Scfm @ 10" (105.4 @ 3"HG). Flow with no throttle plate was
151.7 Scfm @ 10" (306.3 @ 3" HG). I had wanted to flow with no shaft or butterfly, but due to a misunderstanding, this is as close as we can get.
I also tested pressure drop thru the throttle shaft holes by blocking off the fuel feed jet and inserting a probe into the throttle shaft after removing the shim screw. With the throttle fully closed the PD was 2.62" H20, and at full throttle it was 22.1" H20 PD. At first, we thought a leak had developed, but this was the true figure! Apparently the "lift" vacuum developed on both sides of the throttle plate "airfoil" is significant! Keep in mind that gas vapor will occupy about 2.6% of the airflow at normal fuel/air ratios, so the real world flow would be 286.6 Scfm (loss of 7.6 Scfm) at the 3" Hg 2 BBl standard. HTH
