A vacuum assist system attaches to an intake line and an intake manifold of an internal combustion engine having a throttle. The vacuum assist system includes a venturi valve, a reservoir, and a proportionally controlled valve. The proportionally controlled valve is movable between an open position and a closed position. The proportionally controlled valve moved to the open position when the throttle is in the partially open position such that air is flows from the inlet to the intake manifold, from the inlet to the venturi valve, from the venturi valve to the intake manifold, and from the reservoir to the venturi valve. The proportionally controlled valve moves to the closed position when the throttle is in the almost-closed position such that air flows from the inlet to the intake manifold via the intake line and from the reservoir to the intake manifold to reduce the pressure within the reservoir.
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