Suction capability

Bench motors testing gave me some necessity of deeper consideration about the relations between suction capability under the fixed burdening and the diameter of intake venturi. In short, bigger throat does not bring more power, because the requirement of throttle control is the smother transition between low, middle and hi operation. The fact as the upper description was proved on L.M.Cox 15 Medallion motor equipped with OS 25LA carburetor with 4,5mm throat venturi, probably, 3,5 to 4,0 mm might be suitable for the condition of setting Tornado 8 by 4 burdening. But remember here, changing of throat diameter is easily done by just closing a throttle valve at highest position adjusting the Travel rate of motor control on Transmitter. We have some tendency to pay attention only to low speed adjusting, but more attention should be done on highest position. Because, the main needle closing angular position affects deeply on the low speed control adjustment.
The modified main needle valve at a plastic fuel nipple position took effect enough and would endure in actual use, the purpose is eliminating the weight of original one and doing the setting space.
On the other hand, the throat venturi size of ENYA 09-3 with Tornado 7 by 4 was well invited and showed smooth transition of speed control from low to middle and middle to hi, the factory engineer's skilled technique was imagined, the research and development must have done so well.
The necessity to gather certain datum is some indispensable task on this critical researching title, I should carry RPM meter next time.
In addition, same theory might be constructed even on fuel pressurized system like YS regulator and Perry pump system. Deeper consideration should be done!