Mattax.
'None of these carbs are sucking directly from the bowl.'
Yes they are, through the m/jets. And you can remove the m/jets & you will get a horribly rich mixture. If the fuel doesn't come from the bowl, then how would fuel get to the booster/t.bores? The word sucking gets used a lot because it is easier to understand; fuel flows because of a pressure difference. Atmospheric pressure on one side of the jet & venturi vacuum [ depression] on the other side. VV is NOT the same as manifold vacuum.
RB.
Your statements confirm that you know little about how a carb works. The straw example I gave is a perfect simulation of how the AB works & how it's size affects the starting point of the main cct. For those interested in this, find a book [ or internet ] diagram of the main system of a carb & you will see the straw comparison is a perfect fit.
'You ignore air speed'. Uhhhh no actually. You missed it. Suction & airspeed in a carb are mutually dependent. I wanted to keep the straw example simple so it was easy to follow. Air speed through the venturi where the fuel outlet is located is increased when the throttle is opened to increase engine rpm; at the same time, pressure in the venturi decreases. Atmospheric pressure in the bowl will at some point be higher & push fuel out of the nozzle. Adding an air bleed bleeds of some pressure, so more vacuum [ depression ] needs to be created in the venturi to get the fuel to flow. If the AB size is increased, the pressure signal is weakened & more vent vac is reqd to start the flow. This additional vent vac is created by opening the t/blades further to increase engine rpm [ & therefore air speed ]; flow starts. Larger MAB starts the system later [ higher rpm ] & smaller MAB starts at a lower rpm. The straw example is a perfect example of the system works. It is just physics.
