Question about "restrictive" oil filters

[Patman]

A lot of times I have worried that perhaps having a filter with too good of a media might
restrict the oil flow. But how worried should I really be? When I drive the car hard it might go
into bypass but it will do so quick enough that it wouldn't starve the engine right?

And even though during that breif moment of full throttle, I'd be getting no filtering done,
wouldn't it more than make up for during the 99.9% of the time when your engine is not at
full throttle?

I got to thinking about this when I looked at the two more popular Champion made filters,
the Mobil 1 and K&N. The Mobil 1 is made with a fully synthetic media and filters down smaller,
while the K&N is supposedly designed for higher oil flow. But wouldn't the Mobil 1 still be
the better choice for those that drive hard, since they'd get the better filtration overall?

[ July 20, 2002, 10:18 AM: Message edited by: Patman ]

 

[Patman]

I was hoping this topic was going to spark up more discussion.

Thoughts anyone?

 

[sprintman]

I'd use M1 filter if I could find the suckers!! PureONE currently and i wonder how restrictive it or but does that matter in a 626 turbo? Very well made it seems and tough to cut open with as hacksaw.

 

[kalbri]

quote:

---

Originally posted by sprintman:
I'd use M1 filter if I could find the suckers!!

---

You could order them online from here: http://store.yahoo.com/rodi/mob1higefoil.html

I used to get them from the Mobil 1 e-store but they closed it. I'll try the above link next time I need to order.

 

[Patman]

Even when that Mobil 1 store was online, he couldn't have ordered from there, as he doesn't live in the US. I wanted to order Mobil 1 filters for myself, since I live in Canada, and was disappointed to find out they only shipped within the US.

 

[sprintman]

Patman

You got it! Mind set of most US companies is that we live in another universe. Air freight a strange concept to some (not Auto-Rx though).

 

[Neil Womack]

I've seen this discussion before and don't see how the Mobil 1 or PureOne filter can be to restrictive for street use.

This is my reasoning and if I'm wrong please someone stop me as I've been using PureOne filters exclusively for several years.

Automotive Oil pumps are positive displacement pumps. Therefore if a restriction occurs the oil pressure will rise infront of the restriction.

If your oil pressure sending unit is down stream of the oil filter. Then a restrictive filter would show as a pressure drop.

If your oil pressure sending unit is between the pump and the filter then a restrictive filter would show as a pressure increase.

I have experienced neither a drop nor a rise in pressure. Assuming I have not been in by-pass the entire time I can't see how either filter is restrictive.

 

[VaderSS]

If the filter gets too restrictive as the flow builds, the bypass is going to open and allow enough oil to bypass the filter elemnt to maintain flow. THis does not mean that all oil will bypass the filter, just enough to maintain adequate flow.

This is just an example as I don't know when this would happen, and it would be different for each engine, but say the filter becomes too restrictive at 2500 RPM. The valve would bypass, say 5% at this point. At 5000 RPM, it would be bypassing 50% of the oil. Personally, my engine spends the vast majority of it's time under 2000 RPM, so I feel completely safe using the Mobil 1 filter.

Remember, even if your engine revs higher, it's a safe bet that the engine is designed to not flow enough oil to cause a filter to go into bypass at normal operating temps and RPM ranges up to the maximum recommended drain interval, so even if you engine is a high revving engine, it was designed to be that way and should still not cause the filter to bypass except under higher than normal RPMs.

One thing I wonder about; wouldnt a higher than recommended vis oil cause the filter to go into bypass sooner, maybe even at normal ranges? Maybe this is why my manual specifically recommends against 20W50.

Hmmm...

 

[MolaKule]

Vader, (An analogy):

On hydraulic systems that I design and develop (mostly for wood splitters - side business), the only time the filter is actually filtering is when the engine is at idle to fast idle. Now, the hydraulic filter is on the return side to the oil tank. [I place guages all over the place in the development stage to make sure flow and pressures are correct.] You can see the pressure guage on the filter housing (this is a filter housing with internal by-pass, no filter by-pass) drop to zero when the engine or electric motor is at high rpm's, which means the filter is being by-passed at this time.

The rule of thumb in hydraulics is: Slightly dirty oil is better than no oil at all to the hydraulic pump.

I would think the same rule applies in automotive engines. Dirty oil is better than no oil at oil, since no oil means almost instant failure.

I had always thought that the by-pass valve in the engine or "filter" housing was to prevent oil filter blow-outs (when filter flow was zero or in cold weather) and make sure the engine had oil in this situation, dirty or not; while the internal by-pass filter in the filter itself was for making sure oil went to the engine in case the filter became clogged or when infinitely restrictive, as when there was a great enough pressure "differential " accross the filter. It would seem to me a pressure differential would occur under the following conditions and cause the filter's internal by-pass filter to activate when:
1. When the engine's oil pump pressure was greater than oil filter's capability to provide flow under high speed, high oil pressure conditions - the situation for even a new filter;
2. When the filter is so restricted that the pressure differential across the filter is high, as when idling OR when at higher RPMS's - the situation for a dirty filter.

So I think the filter is only filtering at fast idle and is by-passed at most other times. In other words, a full-flow filter is only full flow at idle to fast idle and above this rpm, the filter is 99% by-passed.

 

[MolaKule]

This sentence shoud read: "It would seem to me a pressure differential would occur under the following conditions and cause the filter's internal by-pass "valve" to activate when:

 

[C Willi 01SS]

Just cut open both the Mobil 1 and K&N last week after running them both on my SS for the same mileage. Both are the longer version. Construction and quality is a wash, everything looks identical except the filter media and the color of the seal. The Mobil 1 has more pleats by far. I think both will filter extremely well and the K&N may give up a few microns to Mobil 1 but I like the thoughts of flow being there.
I also like the nut on the K&N with the safety wire holes in it. My '01 SS is 1.5" lower than stock with longtube headers, the headers still hang down below the nut on the K&N.

 

[Bror Jace]

Can someone verify for me that K&N oil filters are actually made by Champion Labs? I had said this before (forgot where I got that impression) and was told that K&N makes their own.

 

[Patman]

Bror, the K&N is made by Champion for sure, here is proof:

http://www.shoclub.com/lubrication-oil/lubrication-oilpart6.htm

(the Author spoke to someone at Champion Labs)

 

[MolaKule]

From the SHO article:
Why the change in slope, and odd behavior between 2500-3000 RPM? I suspect the oil filter by-pass valve opens in this car between 2000 - 3000 rpm trading full flow filtering for quantity. The big question is what happened to the 10 PSI per 1000 RPM rule?

It appears that author and myself feel the same way:
"So I think the filter is only filtering at fast idle and is by-passed at most other times. In other words, a full-flow filter is only full flow at idle to fast idle and above this rpm, the filter is 99% by-passed. "

 

[RalphPWood]

On some GM cars the bypass valve is in the filter mount. There is no bypass valve in the filter. The bypass valve opens a lot more than it needs to. PermaCool makes a teflon plug to block the bypass valve. It is a catalog number 771-14845 in the www.jegs.com catalog. The plug wouldn't be too good for people that neglect their full flow filter. I have been known to screw a pipe plug into mine. Hastings once had a full flow filter packed with cotton. Stilco used about half a roll of toilet paper. They had a big bypass valve that stayed open at all times.
PermaCool makes a sandwich adapter that I like to use with my Motor Guard M-30 submicronic bypass filter. If you use the Chevy V8 sandwich adapter it doesn't have a built in bypass valve. The only oil the full flow filter can get is what comes from the Motor Guard M-30. The bypass valve in the mount stays open. The engine is then a straight bypass system like an old Chevy 6-235 or a 53 Caddy. The universal Catalog number 771-189 or the 771-181 Ford have the built in bypass valve.
I'm putting a Chevy V8 number 771-185 on a 8.2 Detroit but I will have to modify it. The 8.2 Detroit will use two Motor Guard M-30's in parallel. The ideal would be two reusable system 1 full flow filters 888-512561BP also in the Jegs High Performance Catalog. All I need is for the full flow filter to remove the big stuff which is rare in a good engine. The submicronic bypass filter can deal with the small submicronic particles and water that cause most of the engine wear.

Ralph

 

[SteveD2]

quote:

---

Originally posted by MolaKule:
From the SHO article:
Why the change in slope, and odd behavior between 2500-3000 RPM? I suspect the oil filter by-pass valve opens in this car between 2000 - 3000 rpm trading full flow filtering for quantity. The big question is what happened to the 10 PSI per 1000 RPM rule?

It appears that author and myself feel the same way:
"So I think the filter is only filtering at fast idle and is by-passed at most other times. In other words, a full-flow filter is only full flow at idle to fast idle and above this rpm, the filter is 99% by-passed. "

---

A couple of thoughts--
--The engine's oil pump has a pressure regulating valve. When pump output pressure is high, that regulating valve dumps part of the pump output back to the sump and holds a fairly constant oil pressure.

--The so-called bypass valve in the oil filter is more like a relief valve. It doesn't fully bypass the filter and suddenly dump all the oil from the inlet side directly to the outlet side. It maintains a maximum pressure differential across the filter media, and as much oil as possible will still pass through the media. Say a bypass valve is said to have an 8 psid bypass. That valve might start to open at something like 7 psid and be fully open at something like 9 psid. That means that there's still 9 psi difference between the oil on the inlet side of the media and the outlet side forcing oil through the filter media. Only the quantity of oil that won't pass through at 9 psid will move through the bypass valve.

Ken

 

[Patman]

I'm bringing this one back up again as I'm starting to wonder if I should start using the PureONE filters instead of the Premium Plus. Even if the filter was being bypassed under acceleration, it would surely not bypass at a steady highway speed (not at 2000rpm anyways) and it would also not bypass when I'm idling in traffic either (which happens a lot during my daily drive) So in essence, I would estimate that my filter would probably only go into bypass mode maybe 1% of the time, and so during the rest of that time I could enjoy the better filtration of the PureONEs.

Thoughts?

 

[OneQuartLow]

Patman, I wouldn't be concerned. Watch the bypass pressure and GPM rates, especially if sub'ing oversize filters. The SAE test numbers I recall showed PureONE held up very well over long multipass testing.

If it keeps you up at night

you could just install one of the remote dual-filter setups. $40-70 (US) and you would halve the effective pressure.

David

 

[kreativ]

The concern I had with the PureONE was that it seemed so much filter media was being jammed into the canister. This may result in excellent lab results in the single pass and multi pass efficiency tests, but it seems it would be more subject to clogging in real-world conditions over the span of an oil-change interval. And thus, rendering the oil filter ineffective for who knows how many miles until the next oil change.

If possible, I'd prefer less, but higher quality media than is found in the PureONE?

 

[Patman]

kreativ, that's the concern I have too, is that they cram so much material in there that it becomes a restriction to higher flow.

But I don't believe it would plug up fast with dirt though. I think that based on my oil analysis showing low wear metals, and very little dirt getting past the air filter, I don't think my filter would clog up for a very long time. Especially since I run an oversize one, and it's rather large on my Firebird. That's another good point too, since I run an oversize filter, it will flow more oil anyways, since it's less of a restriction.