Bypass Pressure Question

[heypete]

Hi folks,

I was doing a bit of research, and had some questions I hope you guys would be able to answer.

1. First off, does anyone here have the various specs (filtration level, flow rate, bypass pressure rating, etc.) for the Toyota 90915-YZZF1 filter? I can't seem to find this information anywhere.

2. Secondly, I note the Wix 51396 filter (can replace the YZZF1) has a bypass valve that opens at 8-11 PSI and a max flow rate of 7-9 GPM. The Purolator PureOne PL14477, on the other hand, has a bypass valve that opens at 14-18 PSI, with no flow rate specified. Will the higher bypass pressure on the PureOne (or lower on the Wix, depending on which way you look at it) cause any problems?

3. After cutting apart a SuperTech ST4967 and a Toyota YZZF1, I note that the bypass valve on the SuperTech is more strongly sprung, so it would open at a higher pressure. Is this a problem?

For now, I'm sticking with YZZF1s, but I'm thinking of using a PureOne when I'm out of warranty and going for longer OCIs (>10,000mi) and I'd appreciate any information you might provide.

For reference, I have a 2006 Toyota Camry with the 4-cylinder 2AZFE engine.

 

[chad8]

almost all the toyota filters i use and have heard of have a 8-11 psi bypass. Does it really matter. Not at all. Cars rarely go into bypass mode. Now you can attack me all you want , but if you maintain your oci's it should never happen unless you are doing some sludge cleaning.

http://www.wixfilters.com/filterlookup/results.asp?PartNo=90915&Submit=Search

51396
UPC Number: 765809513969
Principal Application: GM Vehicles (99-05), Geo (89-92), Toyota (88-10), Various Ford-New Holland Tractors, Suzuki (96-10), Suzuki Marine Engines
All Applications
Style: Spin-On Lube Filter
Service: Lube
Type: Full Flow
Media: Paper
Height: 3.402
Outer Diameter Top: 2.685
Outer Diameter Bottom: Closed
Thread Size: 3/4-16
By-Pass Valve Setting-PSI: 8-11
Anti-Drain Back Valve: Yes
Burst Pressure-PSI: 400
Max Flow Rate: 7-9 GPM
Nominal Micron Rating: 21

 

[bepperb]

"Does it really matter. Not at all. Cars rarely go into bypass mode"

+1. The filter should seldom to never go into bypass. That isn't the oil pressure, that is the pressure across the media. 10psi drop is a lot, the filter would be clogged with something for that to happen.

 

[Gary Allan]

In my observations the bypass rarely opens ..or rather the PSID is rarely in the range of the bypass valve setting. The time you're in pump relief will produce a variable PSID. After warm up, it's not apparent for the most part. Even the effects of loading work on a warm up curve. If you're only briefly in pump relief, then you're only going to see the effects of loading. I tend to think most here change out their filters at the point where this isn't a factor either. I think many are barely into the half life of the filter when they change it out.

 

[ARCOgraphite]

I prefer the toyota 90915-10004 factory filter over the denso thailand made yzzf1/2 in the 2azfe and 1nzfe applications. I have lost prime using the yzzf1/2 after oil change too many times - and it does not happen with a wix or the purolator. IDK Y, maybe overapplied resin to the paper element on the yzzf? Still a big mystery to me and I dont have a lab at my disposal anymore to study the flow on these filters.

 

[heypete]

Originally Posted By: bepperb
"Does it really matter. Not at all. Cars rarely go into bypass mode"

+1. The filter should seldom to never go into bypass. That isn't the oil pressure, that is the pressure across the media. 10psi drop is a lot, the filter would be clogged with something for that to happen.


I was under the impression that the filter often went into bypass when the oil was thick and cold (though I live in Arizona, I wonder if it ever gets cold enough to matter), but once it warmed up and the thinner oil was able to flow through the filter more easily, the bypass valve then closed.

Is this not the case or, if it is so, is it barely a concern?

 

[SuperBusa]

Originally Posted By: heypete

I was under the impression that the filter often went into bypass when the oil was thick and cold (though I live in Arizona, I wonder if it ever gets cold enough to matter), but once it warmed up and the thinner oil was able to flow through the filter more easily, the bypass valve then closed.

Is this not the case or, if it is so, is it barely a concern?


Yes, the colder it is, the more likely the bypass valve will see some action. Keep in mind that when the oil is very cold and thick that the pump's pressure relief valve may not control as well (dependent on it's exact design), and that could cause a higher PSID in the filter during cold operation and cause the bypass to open more frequently.

Obviously, you do not want to do any high RPM running until the oil gets warmed up and thinned out some ... ie, don't redline after starting the engine at -10 deg F.

 

[Colt45ws]

Usually the most action it sees is right at start up when the pump is pressurizing the system.

 

[bepperb]

"I was under the impression that the filter often went into bypass when the oil was thick and cold (though I live in Arizona, I wonder if it ever gets cold enough to matter), but once it warmed up and the thinner oil was able to flow through the filter more easily, the bypass valve then closed."

After a cold start, at idle most cars only have about 20 psi of oil pressure. If they were losing over half that in the filter, that would be a big deal. Now, if the oil is very thick and the rpm's are higher (which increases oil pressure) and the filter is loaded, then yes I can see how you would hit this limit. Really, though, if an engine were losing 10psi or more at the filter on a regular basis, there is a failure or a design flaw somewhere.