Subaru specialty Filter requirements?

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Hi guys, I just recently learned that my 2008 Legacy GT required a fairly rare and special filter that I can't really get anywhere... From what I understand it calls for an unusually high bypass pressure in the OEM requirement. What exactly does this affect? I normally use the standard Purolator or Frams available at the parts houses and Walmart. It has 170,000 miles on it now and still runs great so it must not be doing much harm...

Standard filter at parts houses is the PH6607 or PL14615 but Subaru and Fram mention it actually calls for a PH9715 which is like a unicorn.

PH9715- Bypass valve setting 16-28psi
PH6607- Bypass valve setting 13psi

Your thoughts and expertise are welcome!
 
Originally Posted by racin4ds
PH9715- Bypass valve setting 16-28psi
PH6607- Bypass valve setting 13psi

Your thoughts and expertise are welcome!


The PH9715 filter IS the factory filter for your car, it is just in a Fram orange can while the one that Subaru provides is in a blue can. They are the exact same aside from outer appearances, the PH9715 is commonly available at many car parts stores.

I have nothing against Wix as I have used several Wix filters in the past, but there have been some manufacturing issues reported recently on this site and also as compared to Fram they have a much smaller amount of filter media in their cans due to the bypass apparatus taking up so much space.

I know a lot of people who get hung up on the bypass spec and I am of the opinion that it was put in place due to flow restrictive filter media in Fram's case with the PH9715 and in large part due to the smaller amount of filter media used in Wix's case. A more free flowing filter like the Fram Ultra Synthetic XH6607 is an excellent alternative to the PH9715 or Wix filters.
 
I would never intentionally use the 6607 size of any filter unless there was no possible way to fit a larger one, plus the 7712 that was on my car when I got it looked like crap internally. The 7055 meets all the Subaru specs and is solidly constructed, and still has decent media size, see here:
NAPA Gold 7055 cut open

Terrible NAPA Gold 7712 cut open

If you are going to use a Fram, I would use the XG7317 as it fits even the tight Impreza exhaust routing and matches well with the block boss. Yes, it does not have the higher bypass valve setting, but it's debatable if it's a concern on a filter with low PSID in operation.
 
Subaru DOES spec a higher by-pass relief pressure than most car makers. WHY they do has been debated for many many years, with no definitive answer.

Some guesses as to why include:

1) A higher flow oil pump, which in some situations ( cold oil, higher rpm's ) can push the filter into by-pass mode more frequently.

2) The use of fine screen banjo bolts in turbo models, which have been prone to clogging on poorly maintained cars. See above ... more by-pass events means the possibility of more unfiltered oil hitting the screens, possibly leading to clogging and oil starvation to the turbo bearing.

Originally Posted by Ignatius


I know a lot of people who get hung up on the bypass spec and I am of the opinion that it was put in place due to flow restrictive filter media ...



Not sure this ^^^ has anything to do with it ...


My Subaru, a non turbo 2.5L, seems to run just fine on either, and has for over 100k miles without issue. However, it does seem to weep oil a bit when using oil filters with the flat type gasket. The oem filter uses a round profile gasket.
 
Originally Posted by racin4ds
Originally Posted by SubieRubyRoo
7712 is TINY... try the 7055.


Do you know if the 7055 has that high bypass pressure?


YES. It is a Subaru specific application.
 
Originally Posted by racin4ds
Originally Posted by SubieRubyRoo
7712 is TINY... try the 7055.


Do you know if the 7055 has that high bypass pressure?

Yes, 27psi.
[Linked Image]
 
Just picked up a couple of these FRAM HP17 oil filters. 22 psi by-pass, high flow media, reinforced construction. Advertised efficiency is 94 % @ 20 mu. Seem very solidly built.

Priced at $ 10 CDN vs $ 15 CDN for a Fram Ultra 7317.

[Linked Image]


[Linked Image]
 
EcoGard and Premium Guard also make proper subaru filters. Their basic filters run $1-2/ea.
 
Originally Posted by Ignatius


The PH9715 filter IS the factory filter for your car, it is just in a Fram orange can while the one that Subaru provides is in a blue can. They are the exact same aside from outer appearances, the PH9715 is commonly available at many car parts stores.


The factory filter is actually black, not blue. Nobody seems to know anything about these filters as you can't buy them anywhere.
 
Originally Posted by badtlc
Originally Posted by Ignatius


The PH9715 filter IS the factory filter for your car, it is just in a Fram orange can while the one that Subaru provides is in a blue can. They are the exact same aside from outer appearances, the PH9715 is commonly available at many car parts stores.


The factory filter is actually black, not blue. Nobody seems to know anything about these filters as you can't buy them anywhere.


To the best of my knowledge the black OEM filter is no different from the blue OEM filter/Fram PH9715 in spec. Some in the past have been made by Roki in Japan, we would be splitting hairs as far as talking about effective differences between black Roki filters and blue Fram filters.
 
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