Gear Shifting Theory

[Dave 53]

At 176 degrees and idle, I'm getting 60 psi, not the specified 14 psi! My 10mm pump was around 14 psi at idle. Do I have a defective overzealous pump?

I'm using 5-40 oil. I'm measuring pressure from the right rear port and temperature from the front port. Bearing clearances are "normal" and I have a big oil cooler.

My pressure gauge is showing about 75 psi once warmed up which is consistent with the 78 psi relief spec.

[Sgt.Gator]

At 176 degrees and idle, I'm getting 60 psi, not the specified 14 psi! My 10mm pump was around 14 psi at idle. Do I have a defective overzealous pump?

I'm using 5-40 oil. I'm measuring pressure from the right rear port and temperature from the front port. Bearing clearances are "normal" and I have a big oil cooler.

My pressure gauge is showing about 75 psi once warmed up which is consistent with the 78 psi relief spec.

I've never seen 60 or 75 psi at idle when the oil is 180 degrees in any of my Subaru engines, race or DD. And especially not from the rear port which always reads lower than the front port. I think your gauge or sensor in that port is probably defective or calibrated wrong.

I guess we should rename this thread to oil pump discussion!

[Dave 53]

I just realized something related to my observation of high oil pressure on my new engine.

At the same time as getting my new engine with an 11mm oil pump, I also switched from a Walmart Fram oil filter to a RCM Race oil filter.

From Flatirons, "Roger Clark Motorsport has developed their Race Oil filter to be the optimal oil filter for the Turbo Subaru EJ Engine. RCM used a very good filter media, and designed the filter to be as efficient as possible so that creates the least restriction possible to the oil as it is traveling into the engine. This results in improved oil pressure across the rpm range with improved oil filtering as well."

By this, I read improved oil pressure to mean increased oil pressure.

Mystery solved?

Be easy enough to try a couple of different oil filters.

[Bob_n_Cincy]

I just charted some data i had from back in January of this year.
My car: 2.5L TD-04 turbo 10MM stock oil pump, Dry sump oil scavenge, liguid / liquid oil cooler, air to water intercooler
Test: 8 minute engine idling at 700 rpm Warm up engine test
OIL: Rotella T6 5w-40 Diesel Oil
Oil pressure and temperature measured at oil filter mounting plate.
Filter Wix 515R (remote mount)
I do not think my electric radiator fan was running during this test.
Cell Phone BTSSM data logger app

My intake is snorkeled so the 58-60 intake temperature is probably same as ambient. (bottom yellow line)
My coolant temp rose from 160 to 180F and was leveling off. (top grey line)
My oil temp rose from 80F to 133F and was clos to leveling off. (orange line)
My oil pressure dropped from 85 PSI and went down to 55PSI as the oil warmed up. (Blue line)
My oil pressure sensor is pretty sensitive that it picks up the pulsation from the Subaru gear pump.



temps.jpg

Let me know if you have any questions. Bob

[Dave 53]

Bob, After reading your sentence: My car: 2.5L TD-04 turbo 10MM stock oil pump, Dry sump oil scavenge,

Do you have some sort of hybrid OEM/dry sump system? My understanding of a dry sump system is that it has a belt driven pump. Are you somehow incorporating a dry sump pan, tank and other required dry sump stuff, but retaining the OEM pump?

[Bob_n_Cincy]

Bob, After reading your sentence: My car: 2.5L TD-04 turbo 10MM stock oil pump, Dry sump oil scavenge,

Do you have some sort of hybrid OEM/dry sump system? My understanding of a dry sump system is that it has a belt driven pump. Are you somehow incorporating a dry sump pan, tank and other required dry sump stuff, but retaining the OEM pump?

Dave, Your description is correct. Here is a link to my system. https://aviaid.com/shopsite_sc/store...mp-Systems.htm

Most of the 818 Dry Sump users are still using the OEM pump. I only have a 2 stage scavenge system while other on here have gone to a 3 or 4 stage scavenge pumps. The high G's of an 818 causes oil to pool in the valve covers.

dry sump 20171220.jpg

Bob

[Sgt.Gator]

Bob, After reading your sentence: My car: 2.5L TD-04 turbo 10MM stock oil pump, Dry sump oil scavenge,

Do you have some sort of hybrid OEM/dry sump system? My understanding of a dry sump system is that it has a belt driven pump. Are you somehow incorporating a dry sump pan, tank and other required dry sump stuff, but retaining the OEM pump?

I too have an Aviaid pump mounted on top of the block in the former A/C space running scavenge only. The OEM pump supplies engine oil pressure. Cosworth worked that way too.
Dailey and Roger Clark run the full shebang dry sump system mounted down low. You have to run a custom header to fit them.
I have a bunch of used DS pumps and other bits if you want to switch to a DS system.

[Dave 53]

I had no idea there was more than one way to skin a dry sump cat. Love learning these new things.

No plans for a dry sump system on my car. Cost is a major issue. Cheaper than a new engine... I get it. But, with the Killer B parts and Arctangent oil control plate, I had over 25 track days and seemed to be doing okay. Until it wasn't. I'm not sure if a dry sump would have saved my engine when it did fail. I had oil pressure when it failed. I'm chocking that one up to user error and the discovery of substandard bearings (and valves). Overheating the engine probably played a part. Now I have a blinking water temp warning light and made huge improvements to radiator air flow. And a warning light that will blink for 15 seconds if oil pressure drops below about 10 psi for even a split second.

5.5 weeks into a "4 to 6 week" wait for the new The Driveshaft Shop axles. Hope they arrive soon so I can sign up for Oct. 9 at Thunderhill raceway.