Subaru Oil Pump Specs as Relates to Filter Bypass

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Check out this thread on LegacyGT.com:
http://legacygt.com/forums/showthread.php?t=147113

For those of you looking for the 23 psi bypass filter for a Subaru, follow the thread to the 2009 Mazda RX8 oil filter comments. Should be an exact fit for Subarus, with a higher can capacity (and more filter media?). Filter #N3R114302. My apologies if this info is already in this thread somewhere.
 
Yeah, that's a good option. The Tokyo Roki's are made very well! Only concern is having the filter close to the exhaust headers... they get *very* hot. However, that's more a theoretical concern than a practical one.
 
Originally Posted By: Jackfortune
Check out this thread on LegacyGT.com:
http://legacygt.com/forums/showthread.php?t=147113


From the spec sheet someone posted on that link, the oil pump's pressure relief setting is 156.6 psi ... Wow!
shocked.gif
 
Originally Posted By: webfors
Originally Posted By: ZeeOSix
Originally Posted By: Jackfortune
Check out this thread on LegacyGT.com:
http://legacygt.com/forums/showthread.php?t=147113


From the spec sheet someone posted on that link, the oil pump's pressure relief setting is 156.6 psi ... Wow!
shocked.gif



Look closer, it's 20-26 psi
grin.gif



Look closer ... I said oil pump's pressure relief setting. There is a difference, I'm well aware of that.
grin.gif
 
Originally Posted By: ZeeOSix
Originally Posted By: webfors
Originally Posted By: ZeeOSix
Originally Posted By: Jackfortune
Check out this thread on LegacyGT.com:
http://legacygt.com/forums/showthread.php?t=147113


From the spec sheet someone posted on that link, the oil pump's pressure relief setting is 156.6 psi ... Wow!
shocked.gif



Look closer, it's 20-26 psi
grin.gif



Look closer ... I said oil pump's pressure relief setting. There is a difference, I'm well aware of that.
grin.gif



ahh... I read to fast
grin.gif
 
Originally Posted By: webfors

ahh... I read to fast
grin.gif



No problem ... I sometimes do too.
wink.gif
With the oil pump able to put a maximum pressure of 156.6 PSI on the oiling system before the pumps starts dumping back to the sump, it's no wonder they have some insane GPM spec on their oil system.

The Subaru's oil system is not something that falls in the "norm" of most street cars.
 
Just when I thought I found an oil filter to stick with, you guys go casting doubt over it
smile.gif
Been using PureOnes for a while now, even did a UOA over winter and everything came back fine, except for some high lead (45ppm in 4K miles when traditionally it has been around 12). Relief valve on the PureOnes is 14-18PSI, OEM is 20-26. I've had UOAs come back with contaminants in oil on the OEM filters when I used to live out in rural area, that's why I switched.
Insight? I'm inclined to think if it ain't broke don't fix it and continue to use PL14612 especially since it's taller than OEM.
I had contacted Purolator, a product engineer said it's fine and not to worry about it, some people said it may be cause of failed turbos due to the oil line screen filter getting clogged because the filter was in bypass mode for too long/when it should not have been.
 
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Originally Posted By: ZeeOSix
............With the oil pump able to put a maximum pressure of 156.6 PSI on the oiling system before the pumps starts dumping back to the sump, it's no wonder they have some insane GPM spec on their oil system.

The Subaru's oil system is not something that falls in the "norm" of most street cars.


That spec is for a Mazda rotary, not a Subaru. The Subaru relief valve is set at 85psi.
 
Originally Posted By: SubLGT
Originally Posted By: ZeeOSix
............With the oil pump able to put a maximum pressure of 156.6 PSI on the oiling system before the pumps starts dumping back to the sump, it's no wonder they have some insane GPM spec on their oil system.

The Subaru's oil system is not something that falls in the "norm" of most street cars.


That spec is for a Mazda rotary, not a Subaru. The Subaru relief valve is set at 85psi.


Yes, you are correct on the RX-8 spec. That's some pretty high oil pressure.
shocked.gif
 
I was gonna post question about filter for my new used 2005 outback. (it has new motor) Did a search and got this interesting thread. Good to know about this psi spec. I get the oem filters for about 6 bucks with washer, I guess I'll stick with that.
 
I am afraid, that a lot of previous media (using by Purolator, Champ, Fram, Mobil, Amsoil, RP) ... can be destroyed under high pressure like 23-28 psi...

And this is the main reason of existing only few filters with high settings of bypass valve...

p.s.
For example, why Pure One PL14615 (announced 3 years ago!) is not in the market since then?
 
Last edited:
Originally Posted By: Izb
I am afraid, that a lot of previous media (using by Purolator, Champ, Fram, Mobil, Amsoil, RP) ... can be destroyed under high pressure like 23-28 psi...

And this is the main reason of existing only few filters with high settings of bypass valve...

p.s.
For example, why Pure One PL14615 (announced 3 years ago!) is not in the market since then?


How do you know the media in the PL14615 is any different than the media in any other PureOne? And how do you know what filter brands would have media that would be destroyed with 23-28 PSID across the media?

A PureOne PL14006 with only 105 sq-in of media area has a low 5 PSID with 12 GPM of hot 5W-30 oil flowing through it.

http://www.bobistheoilguy.com/forums/ubb...451#Post1619451

The Subaru engines don't flow much beyond that, so if Subaru is specifying a 23 PSI bypass valve on their OEM filter, then it's for massive bypass headroom for various reasons (ie, filter loading, expected high engine RPM with cold thick oil, owner's using thicker oils than specified, etc), and/or the filter itself is pretty flow restrictive and has much more than 5 PSID with hot oil at 12 GPM.
 
Originally Posted By: stenerson
I was gonna post question about filter for my new used 2005 outback. (it has new motor) Did a search and got this interesting thread. Good to know about this psi spec. I get the oem filters for about 6 bucks with washer, I guess I'll stick with that.

I've used OEM on my 06 Forester since new with no problems. BTW, check with your local dealerships and see if you can order parts on their website. I get filter/washer for $4.54+tax from my local dealer because I order and pay for them online.
 
Fred Beans Parts has Tokyo Roki for all Subarus with the proper pressure setting (they use Mazda OEMs).

I've been using those and Blue Subaru filters for a while. The Tokyo Roki has more filter area, so I extend my OCIs to 5000k and not the 3750 they recommend.

04+ STi : PKN3R1AA000

2002+ WRX : PKN3R1AA000

2005-2009 Legacy GT : PKN3R1AA000

2010+ Legacy GT : PKN3R16010

2013+ BRZ : PKN3R16010
 
I wonder about my Subaru race engine oil filter after reading this whole mofo thread. I put 70 track hours on a new motor and when I tore it down it looked great. Oil analysis was fine.
My Dual AVCS engine was dyno'd at 395 AWD HP and based off a new, 2011 short-block. I ran an 11mm oil pump. I was running a remote filter, a K&N HP-3001 which has only a 8-11 PSI relief valve rating. I usually had 85 PSI at 6K. I also ran a large oil cooler. I had a nine quart oil capacity. I ran only Royal Purple XPR 5W-30 or 10-40. Subaru says the filter should have a 23 PSID relief valve.

Now, I have a new 430 AWDHP DAVCS engine with a 12mm pump and a Peterson external pressure relief valve and the same K&N oil filter. The 12mm pump is capable of more pressure (85 vs 43) but is rated at 6% less flow than the 11mm pump @5,000 RPM, but I will be taking it to 7,500. The engine is a few tenths looser on the rods and mains. It just came off the dyno. 85 PSI+ is no problem.
Should I consider looking for a higher bypass pressure filter? There is a fairly large K&N HP-2005, where the bypass is rated at 27-35 PSID.
The thing is that I've had no oiling issues. While I've ran this motor two of my track buddies with STi's have thrown rods through their cases. They ran stock sized filters in the stock (very hot) location. No oil coolers. Both were in the 370 AWD HP range.
I know this is pretty anecdotal but my setup works for me. You would think that I would have more oil bypassing and more and bearing wear.
I am in process of building yet another (AVCS) engine for my DD. It will have a similar setup to the first old motor, but a little less power and not be a track car. I'm wondering what remote filter would be best for these?
 
Originally Posted By: Scargo
Now, I have a new 430 AWDHP DAVCS engine with a 12mm pump and a Peterson external pressure relief valve and the same K&N oil filter. The 12mm pump is capable of more pressure (85 vs 43) but is rated at 6% less flow than the 11mm pump @5,000 RPM, but I will be taking it to 7,500. The engine is a few tenths looser on the rods and mains. It just came off the dyno. 85 PSI+ is no problem.

Should I consider looking for a higher bypass pressure filter? There is a fairly large K&N HP-2005, where the bypass is rated at 27-35 PSID.


I thought most Subarus had really high volume output oil pumps with a high pressure relief setting (way higher than 43 PSI) as mentioned many times in this thread. That was the main theory why Subaru oil filters had such a high bypass valve setting - the high oil flow through the filter will cause more delta-p and therefore should have a higher bypass setting.

Engine oil pressure corresponds to the effort required by the pump to put the pump's output volume through the engine's oiling system. Seems like if the new 12 mm pump puts out less flow volume at 5,000 RPM, and your bearings are setup with a looser tolerance, then the observed pressure should be less at 5,000 RPM (compared to the old 11 mm pump) if running the same oil at the same temperatures. I'm assuming you've bumped up the new pump's pressure relief setting to allow more max pressure, which should mean more oil flow to the engine at higher PRM due to higher pump relief.

Originally Posted By: Scargo
The thing is that I've had no oiling issues. While I've ran this motor two of my track buddies with STi's have thrown rods through their cases. They ran stock sized filters in the stock (very hot) location. No oil coolers. Both were in the 370 AWD HP range.


Any ideas what oil filter brand(s) they ran? With no oil coolers, they probably threw a rod because the the oil thinned out way too much and caused bearing metal-to-metal contact and eventually bearing lock-up and rod failure.

Originally Posted By: Scargo
I know this is pretty anecdotal but my setup works for me. You would think that I would have more oil bypassing and more and bearing wear.


It's been mentioned may times that the bypass setting of oil filters has a lot to do with the filter's flow resistance, and the expected max debris loading and max expected oil flow. As mentioned already, many believe the Subaru filter bypass is set high because of the unusually high pump volume, and who knows how restrictive the filter itself may be as part of the equation - could be part of the reason their bypass is set high. Subaru may also set their bypass really high just to ensure the filter hardly ever bypasses in the most extreme use conditions, similar to what's done with "racing filters".

BTW, Fram has a new racing filter with metal end caps and a high bypass valve setting (in the 20s), high flow specs with most likely a better efficiency than the K&N ... might be another filter to consider also.

https://bobistheoilguy.com/forums/ubbthr...eas#Post4263567
 
Originally Posted By: ZeeOSix
Originally Posted By: Scargo
Now, I have a new 430 AWDHP DAVCS engine with a 12mm pump and a Peterson external pressure relief valve and the same K&N oil filter. The 12mm pump is capable of more pressure (85 vs 43) but is rated at 6% less flow than the 11mm pump @5,000 RPM, but I will be taking it to 7,500. The engine is a few tenths looser on the rods and mains. It just came off the dyno. 85 PSI+ is no problem.

Should I consider looking for a higher bypass pressure filter? There is a fairly large K&N HP-2005, where the bypass is rated at 27-35 PSID.


I thought most Subarus had really high volume output oil pumps with a high pressure relief setting (way higher than 43 PSI) as mentioned many times in this thread. That was the main theory why Subaru oil filters had such a high bypass valve setting - the high oil flow through the filter will cause more delta-p and therefore should have a higher bypass setting. Many will run an additional shim on the 11mm pump if the motor is going to see race duty. This is with stock bearing clearances. I have a huge Setrab oil cooler and nine quart capacity when the Accusump is included. I've never had overheating conditions with water or oil (in past engine).

Engine oil pressure corresponds to the effort required by the pump to put the pump's output volume through the engine's oiling system. Seems like if the new 12 mm pump puts out less flow volume at 5,000 RPM, and your bearings are setup with a looser tolerance, then the observed pressure should be less at 5,000 RPM (compared to the old 11 mm pump) if running the same oil at the same temperatures. I'm assuming you've bumped up the new pump's pressure relief setting to allow more max pressure, which should mean more oil flow to the engine at higher PRM due to higher pump relief.
The 12mm pump seems like it should be capable of more volume but is listed as making more pressure than an 11MM pump. However, I ported the pump and the galleys and will be revving the engine to 7,500 RPM. The Peterson valve seems to be doing a good job of controlling the pressure. I just have a little more clearance on the bearings beyond stock. 525-550 hP is not an outrageous amount of power. It is all well-balanced, too.

Originally Posted By: Scargo
The thing is that I've had no oiling issues. While I've ran this motor two of my track buddies with STi's have thrown rods through their cases. They ran stock sized filters in the stock (very hot) location. No oil coolers. Both were in the 370 AWD HP range.


Any ideas what oil filter brand(s) they ran? With no oil coolers, they probably threw a rod because the the oil thinned out way too much and caused bearing metal-to-metal contact and eventually bearing lock-up and rod failure.

Originally Posted By: Scargo
I know this is pretty anecdotal but my setup works for me. You would think that I would have more oil bypassing and more and bearing wear.


It's been mentioned may times that the bypass setting of oil filters has a lot to do with the filter's flow resistance, and the expected max debris loading and max expected oil flow. As mentioned already, many believe the Subaru filter bypass is set high because of the unusually high pump volume, and who knows how restrictive the filter itself may be as part of the equation - could be part of the reason their bypass is set high. Subaru may also set their bypass really high just to ensure the filter hardly ever bypasses in the most extreme use conditions, similar to what's done with "racing filters". My goal is to run 5-30 oil.

BTW, Fram has a new racing filter with metal end caps and a high bypass valve setting (in the 20s), high flow specs with most likely a better efficiency than the K&N ... might be another filter to consider also.

https://bobistheoilguy.com/forums/ubbthr...eas#Post4263567
 
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