I've read all 50 pages, legitimately, condensing the main points to determine my own post-MAF setup and testing.
I've read here that for pre-turbo jets which can only be installed further upstream (post-MAF) and not at the compressor based on OEM turbo housings should be installed to spray against the direction of oncoming air post MAF to atomize most effectively (basically spraying at the back of the MAF housings the incoming air breaks up the fluid better).
Based on my VW GTI's engine layout and more specifically the intake layout, I've been studying the air velocity within a 90 degree bend (the bend leading to the horizontal intake pipe running across the back of the engine (from the black MAF housing to the beginning of the long straight).
VW GTI Intake layout:
This video shows in yellow the highest velocity stream which would help atomize any water meth spraying inside of this intake pipe:
https://www.youtube.com/watch?v=OvprEu-yH-A
Based on the video example alone, should I install the jet at the top of the horizontal pipe to spray against (into) the yellow stream? Or at the bottom of the pipe to spray into (with) the yellow stream?
When people place jets within the intake tract, are they accounting for flow diagrams or streams?