Oil & Fuel Oil Filter Flow - Physical Limitation

[WinterDeere]

Oil is incompressible, so up to the point where you blow out the can, volume in = volume out. Once purged of air, that translates to flow rate in = flow rate out. The beautiful simplicity of incompressible fluids.

Gasses are a bit more tricky, but allow us to game the system by playing pressure against restriction to achieve variable flow rates.

 

[DarkBlack]

When I read it I thought the same - intuitively at least , but I do not know enough about the dynamics of oil flow to say so factually.

I can see small holes as an issue with very cold viscous oil, but I ask myself why would Fram make small holes (that are more restrictive?) when it would be just as easy to make bigger holes?? Why would Fram go out of their way to produce an inferior product?? Hoping for failure? Orange oil filters with small inlet holes sell better than the competition??

I would think someone with more knowledge of oil flow dynamics would have pointed this out by now.

Intuitively, my speculation is it is all about marketing - perhaps their market research shows enough/targetted people like the look, colour and small holes?? I don't know and after looking over their tech info on their website they certainly don't say much other than they have 12 inlet holes and M20 return.

Intuitively, I am with you - bigger holes are better - at least as far as oil filters are concerned.

What I stated about hole volume is true, no matter if it’s cold viscous oil or water, but it is only a consideration for the hole area only.

I bring up the anti drain valve again.
It blocks the holes, varying from completely blocked, when there is no flow, to modestly blocked when there is heavy oil flow. It’s a significant flow restriction.
Try opening it with your finger or a screwdriver through just one hole.
A few larger baseplate holes cause the oil to overcome the valve pressure , in just a few locations, causing the anti drain back valve to scallop in form during operation.
More smaller holes allow the oil to lift the valve in a more even radial pattern and keeps the pliable valve material flatter in shape, more evenly lifting it, and keeping its shape more likely to properly seal when you shut off your engine. This becomes more important as the valve slightly hardens with age. Point is there’s more considerations.

I can’t speak for Fram’s particular reason though.

 

[WinterDeere]

Here you can see what an anti drainback valve is, and how it works. I stopped watching half way thru, when the guy was noting it doesn't prevent reverse draining thru center hole, as I believe the oil pump on the engine would (mostly) prevent that.

 

[DarkBlack]

Here you can see what an anti drainback valve is, and how it works. I stopped watching half way thru, when the guy was noting it doesn't prevent reverse draining thru center hole, as I believe the oil pump on the engine would (mostly) prevent that.

His experiment is deeply flawed.
1) tipping over the can is initially just draining out oil he poured into the center outlet tube
2) The center outlet tube feeds to elevated exit points..the crankshaft being the lowest. Allow it free drain out of the can is unrealistic.
3) He’s allowing free air to enter the can. In reality, the entry holes are airtight plumbed to the oil pump with the pump pickup submerged in oil at the pan bottom. For oil to freely flow out the center tube, replacement oil would be sucked up the pump pickup.

I do like his little improvised window on the can though

 

[WinterDeere]

Agreed on all points, DarkBlack. But it was still a good view at the antidrainback valve on the can he had cut open, that I suspect few have seen.