Flow rates: Filters vs. pumps.

[MarkC]

So, I've seen specs(or claims) giving flow rates for various filters, such as 3-7 gpm for Purolators, 12-16(or something) for K&N, etc. But does anybody know how much the oil pumps in the actual vehicles flow? Can a Jeep 4.0 , for example, even flow 12-16 gpm? Where would someone look to find this information?

 

[Brian Barnhart]

Generally, SAE (according to their HS-806 Oil Filter Test Procedure) rates filters by flow and media envelope volume in 18 classes from A to U. These correspond to flow rates of 2.1 GPM (Class A) up to 95 GPM (Class U). Based on media envelope volume, I’d say typical auto/truck engine oil filters fall into categories A through perhaps E. This corresponds to flow ratings of about 2 to 5 GPM.

The pressure drop across the filter does not appear to be specified. However, filter capacity/contaminant removal tests generally end when 75% of the bypass valve setting is reached (8 PSI) for automotive filters.

 

[Brian Barnhart]

After reviewing my reply to MarkC's post, it looks like I got off track and didn't really answer his questions. So, for what it's worth...

quote:

---

But does anybody know how much the oil pumps in the actual vehicles flow?

---

I've not seen oil pump flow data published anywhere. Based on SAE oil filter test procedures, I estimate it to be in the 2-5 GPM range.

quote:

---

Can a Jeep 4.0 , for example, even flow 12-16 gpm?

---

I doubt it. In fact, it better not. Think about it. At a flow rate of 15GPM, the Jeep's hefty 6 quart sump would be essentially dry in just 6 seconds, hardly enough time for much of the oil to flow back into the sump.

quote:

---

Where would someone look to find this information?

---

I don't know. It's not in my '96 Jeep Cherokee factory service manual. The 2-5 GPM number I suggested above is based on deductions of SAE oil filter test parameters and typical automotive sump capacities.

 

[MarkC]

Thanks Brian.
I'm still obsessing over oil filters; filtration vs. flow, which is more important. Been using those PureOnes for a bit, but trying to make sure they're not 'starving' the engine. Guess not, I rarely hear anything on startup that sounds unusual for a 4.0. Just wondering about switching to something else for a while this winter.

 

[BOBISTHEOILGUY]

Brain is correct in his assumptions.

Normal oil pumps produce approx up to 3.5 gpm in the engine. There are high output oil pumps but only in specialized situations would one use that.

The pump I have on my test is a standard (302ford? if memory serves) small v8 oil pump. I will produce a straight 40lb pressure though an empty filter with less than a .05 pressure drop across it. This flow will be measured and should fall in the standard oil pump range of 3.5gals or less.

From that, you'll be able to see what kind of drop will affect what amount of oil passes as we will measure the output of oil through each filter test.

The 3.5 gpm info was obtained from an oil pump manufacture who makes standard and high performance oil pumps.