IAB
Intake Air Butterflies a valve that opens and closes to switch between two available passages in the intake manifold.
Adapted from pgmfi.org wiki
Intake Air Butterflies - a valve that opens and closes to switch between two available passages in the intake manifold. This is done to allow the use of a longer runner at low RPMs for increased torque and a short runner at high RPMs for more power. Found on GSR and H22A intake manifolds.
Credits and source
Source Adapted from IAB on pgmfi.org wiki. Licensed under CC BY-NC-SA 1.0.