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Replacing blue OEM oil filter with black?


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Black Roki filter would be what is available everywhere else other than USDM. The blue filters are made by Fram/ Honeywell to Subaru spec which obviously isn't very high except the 23 PSI requirement.. If you want to be different, you can import them for about $20 shipping through partsouq.com if you want a good OEM filter.

 

If you want just a good filter, Wix branded or Napa Gold..

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I have always used the blue filters on 2.2 and 2.5 EJ motors. Just wondering if the black Roki filter is a direct replacement and worth the cost.

 

your engine will blow up. 

 

actually it doesn't matter.  you can run 300,000 miles all day long on a Subaru with whatever oil filter is on sale, regardless of the endless diatribes about bypass filters.  not that i'm encouraging flippancy, but reality is reality. 

 

is there one bit of statistically meaningful quantitative data about average, well maintained daily driver engine issues due to oil filters?

all i've seen is armchair quarterbacking of the same regurgitated attitudes for 20 years.

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I'm fixing to change some of that. I have on order a differential pressure sending unit that I can bring into Romraider via an analog to USB adaptor made by phidgits. This will allow me to determine under what conditions the 23 psi bypass goes into effect. It definitely opens on cold start and potentially under high RPM. 

 

Of course none of this matters on a factory engine. We are building high HP turbocharger engines with larger oil pumps, increased bearing clearances, running 15w50 race oil. It matters for me as an engine builder so I can have real data to prove to myself that I'm making the right recommendations on oils, clearances, and pump sizes for racing purposes. We want to run synthetic media filters such as the Amsoil offerings but they don't meet the bypass specs. The idea is to find out which filters actually create a bypass situation on cold start by measuring differential pressure across the element under varying conditions. 

 

But Gary is right. None of this matters on a stock engine. The Wix filter has a better design for the bypass and it's cheaper than the blue Fram so regardless it's a better choice even if it's a one in a billion shot that the filter could cause or prevent a failure. 

 

GD

Edited by GeneralDisorder
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Something about the bypass always bugged me- is there any possible 'backflush' when it opens, sending trapped particles past the filter?

Love it! please confuse this diluted topic with good questions!

 

Not to sound flippant of course, make good decisions.

Edited by grossgary
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When you say, blue filters are junk. Are you referring to the blue Subaru filters from the dealership?

Yes. He also goes on to say that for most people this conversation doesn't really matter. Read his other reply.

 

But yes I'm surprised your engine isn't already a door stop if you don't know this by now about the blue filter.

 

 

 

I'm totally kidding. Filter matters not on average daily drivers.

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WIX came out with a filter that meets the bypass spec and has an upfront bypass valve. It's also cheaper. Both are non sythetic media that couldn't hope to trap particulate sizes that cause the majority of damaging engine wear any better than 50%. So you be the judge.....

 

The old VW air-cooled aluminum block engines had no filter...... 

 

GD

Edited by GeneralDisorder
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I find it odd. About 2 years ago on this forum there was a big debate on filters, and the over welming outcome was only use Subaru filters.

 

Have the oem filters changed since then?

 

 

It's not really odd because oil questions and discussions are ongoing every day and never ending and have been for a long time. They number of opinions is infinite, so you'll never get a consensus in a billion years. 

Since it doesn't matter - everyone is right and quantitative evaluation of actual engine longevity and causation verses correlation is sparse. 

 

It's like debating if a helmet offers better protection in an elevator or waxing a car makes the engine last longer.  An armchair quarterback can say "yes, look at the physical properties involved, and data and formulas" - but practically it's nearly meaningless.

 

The "300,000 mile Subaru secret" is something like this:  Change often, repair leaks and engine issues immediately, and run synthetic in certain engines/situations, follow the weights recommended by the owners manual.

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Particle size can be too big or too small to matter-

 

if it can't touch 2 metal surfaces sliding past each other at the same time, too small to matter.

 

If it gets jammed in the gap between 2 sliding surfaces and one of them is soft enough to embed the particle (plain bearing), it's too big to matter.

 

 

I'm actually interested in the bypass condition, as a matter of academic interest- could debris be dislodged and sent past the filter?

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With the factory filter, yes. Debris that has already been trapped can *theoretically* be washed back into the engine during a bypass "event". With the WIX upfront bypass this is not possible. That, in conjunction with the cheaper price point and correct bypass PSI setting per Subaru makes it the clear choice for the most superior "cheap" filter. As I said, it doesn't matter in practice. But, in the one-in-a-billion event where a filter may stop something truly engine damaging, the WIX is a better design at a cheaper price point. That makes it the best choice. Again, it doesn't matter. But if you want to spend more and get less, even theoretically...... then perhaps logic escapes you...... I can't help with that. 

 

GD

Edited by GeneralDisorder
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