[XfireZ51]

Todd,

Think of it this way. At high vacuum, ie idle, fuel is being literally sucked out of injector. At WOT or very close to 100kPa, getting the fuel into the airflow takes more pressure therefore a 1:1 VAFPR to maintain the same amount of fuel flowing whether #/hr or gms/sec. In TBI systems the injector is always exposed to atmospheric pressure. Getting fuel into the airflow is a question of "shearing" the fuel off the Venturi walls as the air rushes by in order to atomize it. But TBI systems run at maybe 10-14psi. Atomization is where direct injection really shines due to the much higher pressures.