Louvers VS Holes

[4WD]

Time to dust off this picture again - this looked horrible looking in the threaded outlet … but …
These things are 3D and can face 180° opposite …

 

[ZeeOSix]

^^^ They look to be opened pretty good if looking down the center tube - left side of 2nd photo. Just need to look down the center tube at the right angle with a good LED flashlight.

 

[ZeeOSix]

I believe the louvered design is supposed to actually flow better as well as maintain a stronger core. It would of course depend on if the louvers were properly punched through or not.

"Flow better" means less delta-p if the flow is the same (PD oil pump). I doubt the reduction in delta-p is much - maybe 1 psi, which wouldn't make any real difference to the oil pump. If they are really choked down (like in post 72) they'd be increasing delta-p.

 

[SilverDreki]

Looking at the louvered filter from the top doesn't show the louvers facing in the opposite direction. Inconclusive data here.

 

[CR94]

I believe the louvered design is supposed to actually flow better as well as maintain a stronger core. It would of course depend on if the louvers were properly punched through or not.

I don't know about that, but louvers have the advantage to both manufacturer and user that there's no risk of a loose or hinging chad (punched-out metal scrap) ending up in the filter.