They do a pretty good impression of an Idle-Air Bypass. Just like the holes I drill in the Primary throttle blades that some guys frown upon. Quick, easy, and cheap.
True, that is one of the useful things about the adjustable unit.
I can adjust my PCV with an Allen wrench in seconds without unbolting anything. :p
What do you do if you want the holes in your butterflies bigger?
How about smaller? :rolleyes: