EGR blocked and butterfly removed-

[Dr Gary]

An old post by "the ferret" says "Block EGR.....do away with butterfly" . Other NADS stuff in that post.
Can anyone explain which butterfly (I see two in the inlet), and what is the effect?
Is it necessary because the EGR is not functioning.

Is the EGR valve "Normally Closed" or "Normally Open" so if the power is disconnected, does that block the EGR flow or keep it wide open?
Thanks

[mudski]

Block the EGR yes but I Think the butterfly in the ZD's stays closed and richens the fuel/ air mixture until the engine reached operating temp and then is fully open. On the 2.8's you can remove the butterfly.