Baseplate holes: Number and Size?

[Brons2]

Since I have purchased my new Nissan Titan, I have been acquiring some oil filters for it. There seems to be a lot of different designs for the number and size of holes that let the oil into the filter. So far the Wix filter seems to have the most surface area "holed out" to provide flow to the filter. I'm gonna get a few more to add to my collection and compare, including the OEM Nissan filter and a Baldwin.

So far I have:

Wix
SuperTech
Fram (have no intention of using...)
Purolator

So I guess my question is, why would a person not use the filter with the most and largest holes for best flow? I got excellent results with the Wix filter on my old truck.

 

[Bill Kapaun]

When you consider that the oil is under pressure, what filter would you consider to have inadequate flow due to the area of the holes?
Consider the area of the hole on a garden hose and GPM!

 

[Brons2]

I have not tested any of them for flow of course.

 

[Gary Allan]

They don't impact the flow at all. They may impact the upstream pressure behind them ..but the downstream flow is 100% the same assuming that the relief in the pump is not opened.

This is why Ralph only has to open up that little Permacool poppet valve on the adapter on rare occasions to route the oil through the TP filter. The flow doesn't change ..only the upstream pressure. Since the flow doesn't change (except rarely) the pressure at the sender doesn't change (indexed for temp/visc).

 

[Bill Kapaun]

Who's Ralph?

My point was-
I'm not aware of any filter that has inadequate hole area. Adding more isn't going to buy you anything.
It's like being twice as pregnant! You are or you aren't!

 

[Gary Allan]

With a member # as low as yours ...I find it hard to believe that you don't know who Ralph is. Especially when referring to drilling holes in Permacool adapters...anyway....
This is "Ralph"

 

[XS650]

A rough rule of thumb in hydraulics is that you should keep fluid velocities under about 12 ft/sec in low pressure hydraulic lines (our engine oil pressures are low pressure by hydraulic system standards) . You can run it through an occasional fitting faster than that.

So let's work backwards.

Assume about 6 gal/min oil flow. That would be 1.9 ft/sec if there was 1 in^2 of hole area.

Any hole area much over 1.9/12 = 0.16 inches^2 would be acceptable by that crude criteria.

I just measured a Napa 1334 Filter base and it has 8 ea 0.23 dia holes. A 0.23 hole is 0.041 in^2 so only 1/2 the holes are needed for real low flow restriction.

The filters with the least amount of baseplate hole area in Grease's study were the Frams (who else

) at 0.297 inches total, so even Fram has plenty of baseplate hole area.

 

[Filter guy]

Your looking at 1/2 of the equation..

What goes in must come out.

The inlet holes, those in the back plate, need to equal the outlet hole ( the threaded area).

Filter companies will make sure that the inlet hole are equal or is slightly bigger in area than the threaded outlet hole.

Whether the hole is round, square, oblong or what ever is based on who stamps the backplate out.

 

[XS650]

quote:

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Originally posted by Filter guy:
Your looking at 1/2 of the equation..

What goes in must come out.

The inlet holes, those in the back plate, need to equal the outlet hole ( the threaded area).

---

Nonsense.

 

[Gary Allan]

quote:

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You can run it through an occasional fitting faster than that.

---

I agree. We're also dealing with (effectively) orifices here. They don't subscribe to the normal linear pressure/flow/resistance rationals that most of us (non-engineer types) are familiar with. That is, going from a 1/2" pipe to a 1/4" pipe is different than having a 1/4" washer/restrictor in a 1/2" pipe.

 

[XS650]

quote:

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Originally posted by Gary Allan:

quote:

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You can run it through an occasional fitting faster than that.

---

I agree. We're also dealing with (effectively) orifices here. They don't subscribe to the normal linear pressure/flow/resistance rationals that most of us (non-engineer types) are familiar with. That is, going from a 1/2" pipe to a 1/4" pipe is different than having a 1/4" washer/restrictor in a 1/2" pipe.

---

The important thing is that the filter mfrs made the holes big enough that they are a non-issue.

It is interesting but not surprising that Frams had the least area. Figures though, it costs at least 10^-27 cent less per hole to make them the size Fram uses compared to the larger sizes other companies use.

 

[T-Keith]

I havn't found a filter that had less area in the holes then the center hole. At least in my application.

-T

 

[Gary Allan]

I'm still of the belief that the media restrictions, however high or numberous, are not an issue in the pressure seen at the sender ..except when the oil pump bypass is breached.

Let's assume that we have, effectively, a slightly variable current dependant power supply. I'm using strained nomenclature here ..but most of you will filter out the pertanent message. The main oil galley from the filter to the crank (or where ever) is of a certain length and diameter. At a given flow rate (velocity), at a given viscosity, it will yield a given pressure. Now this basically means that any upstream differences are independant of this and any intermediate changes in velocity and the subsequent changes in localized pressure basically have no impact in either pressure at the sender ..nor volume to the engine. Again qualified for the oil pump bypass not being breached.

Can anyone agree with me ..or connect the dots to where I may be mistaken

So, I'd say, that it really doesn't matter if you have small holes or big ones ..matched or mismatched ..generally speaking.

 

[XS650]

quote:

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Originally posted by Gary Allan:


So, I'd say, that it really doesn't matter if you have small holes or big ones ..matched or mismatched ..generally speaking.

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Let's not get personal

As long as the hole area is adequate to assure a pressure drop through the holes at realistic flow rates that is extremely small compared to system pressure, then the hole size is adequate.

Most filter companies in Grease's study are in the 0.32 to 0.39 in^2 of inlet hole area range. Two brands are higher and one filter company with a propensity for cheesy glued on end caps is at 0.227 in^2.

Even that is reasonable for the job, but closer than necessary to being a significant restriction. A hole area that is much better than just adequate costs essentially the same to manufacture as one that is adequate.

This is all moot though, because friends don't let friends use Fram.

 

[labman]

For the same area, fewer, larger holes should flow more. I think the holes even Fram filters are much larger than the oil galleys.

 

[kenw]

quote:

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Originally posted by XS650:

quote:

---

Originally posted by Filter guy:
Your looking at 1/2 of the equation..

What goes in must come out.

The inlet holes, those in the back plate, need to equal the outlet hole ( the threaded area).

---

Nonsense.

---

please explain why you do NOT believe this.

 

[Ugly3]

quote:

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Originally posted by labman:
For the same area, fewer, larger holes should flow more. I think the holes even Fram filters are much larger than the oil galleys.

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Exactly.

 

[XS650]

quote:

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Originally posted by kenw:

quote:

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Originally posted by XS650:

quote:

---

Originally posted by Filter guy:
Your looking at 1/2 of the equation..

What goes in must come out.

The inlet holes, those in the back plate, need to equal the outlet hole ( the threaded area).

---

Nonsense.

---

please explain why you do NOT believe this.

---

Each restriction results in a pressure drop as the oil is pumped through it. If you were to make the outlet hole so large that it offered virtually no restriction, the restriction at the inlet wouldn't change. There is no direct relationship between them other than the fact that they are both sources of presure drop as oil is pumped through the filter. They are independant sources of restriction, Changing one has no effect on the other.

 

[427Z06]

May as well stick in my two cents in.

My views closely reflect XS650's.

 

[427Z06]

I have to add, I've never been to concerned with the number and sizes of holes on oil filters as they seem to have always been adequate.

What does have my intrigue though is the miniature filters they have been specing on new cars lately.
Big V-8s use to use filters of the size of a Wix 51060 (3.7" Dia. x 5.2" H) but on the Titan 5.6L they're specing something of the size of the Wix 51356 (2.7" Dia. x 3.4" H). A Ford SHO 3.0L V6 would use something of the size of a ST3600 (2.9" Dia x 4.8" H) but the Nissan 3.5L V6 specs something the size of a ST6607 (2.7" Dia. x 2.6" H).

Here's a pic to visually compare the sizes.

ST6607 vs ST3600


What's up with this?

[ November 13, 2004, 10:56 PM: Message edited by: 427Z06 ]