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I started knocking down the casting behind the TB on the plenum while I was rebuilding the engine and noticed that there are ports directly behind this ridge. Is the ridge there for turbulence to create vacuum in the bottom chamber of the plenum body? If so, how will removing this ridge affect a mass air pressure engine?
Re: Can porting L98 plenum affect vacuum? (torque91)
Torque,
All the procedures I have seen knock off these ridges. Those holes are where the EGR system injects exhaust gasses. It will not effect manifold vacuum, if that is what you mean.