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Old 07-28-2020, 12:16 AM   #226
subaru_gc8
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Quote:
Originally Posted by Waddlz View Post
You are not. The pressure drop is normal.

The DAVCs will drop pressure like that, and is why Subaru started using the 11mm in the cars with DAVCs

My 2012 will do exactly the same thing as killer-b is showing, but my buddies GD with SAVCs does not.
Oh okay thanks for the explination
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Old 10-02-2020, 10:51 AM   #227
pcampbell
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Any thoughts as to what sort of oil pressure do I want to see up to say 7300 rpm on an 2005 EJ253 (non-AVLS)? I am trying to figure out if it needs a 9mm or if 7mm is fine. Currently my stock 7mm with T6 gives me about 65psi-70psi at high rpms, I haven't hit 7000 yet.

I know what you are thinking... it won't make any power at 7300rpm. Cams and centrifugal supercharger on there so I do not expect power to drop off.

Last edited by pcampbell; 10-02-2020 at 12:57 PM.
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Old 10-02-2020, 09:35 PM   #228
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I'd want to see ~85psi or better at that RPM. If the pump is sized right, the pressure will scale up with RPM. If the pump is too big, pressure drop may occur.
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Old 10-02-2020, 09:36 PM   #229
murrdogg24
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funny this thread showed up in new posts, as I just discovered today I have a leak on my oil pump on my EJ205...
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Old 10-10-2020, 05:17 PM   #230
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Default Why you don't need GR (11mm) Oil Pump in GD (10mm) Engine

Quote:
Originally Posted by KillerBMotorsport View Post
I'd want to see ~85psi or better at that RPM. If the pump is sized right, the pressure will scale up with RPM. If the pump is too big, pressure drop may occur.


Thanks, it is a stock 7mm pump. If it does fine until higher rpms and then falls off should it be shimmed?


I want to say that I am seeing around 60psi at 6000rpm. I'm trying to rev to 7000 though. I'm not exactly sure if I should be looking at a 9mm pump, thicker oil (currently using 5w40 rotella t6) or shimming. Another option is a new 7mm pump, if perhaps the old stock one is worn and has lost some of it pumping ability. Perhaps the bearing clearances are higher due to age (208k miles).

there is no avls or avcs and also the supercharger is self contained oil so itís pretty basic.

Last edited by pcampbell; 10-22-2020 at 06:56 AM.
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Old 10-26-2020, 08:55 AM   #231
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One other question. I know the pump screws have a tendency to back out. Can they back out enough to affect pumping?
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Old 10-26-2020, 09:48 AM   #232
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Quote:
Originally Posted by pcampbell View Post
One other question. I know the pump screws have a tendency to back out. Can they back out enough to affect pumping?
Absolutely. One, or worse two, loose screws can adversely effect pressure. Also will depend which screws (suction side, pump side, or between).
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Old 10-26-2020, 11:39 PM   #233
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Quote:
Originally Posted by KillerBMotorsport View Post
I'd want to see ~85psi or better at that RPM. If the pump is sized right, the pressure will scale up with RPM. If the pump is too big, pressure drop may occur.
Iíve noticed an oil pressure drop in the higher rpms that lead me back to this thread. Iíd read it before, but since you bumped it in April, I reread it... despite the pissing match in the middle, a lot of good info here. I see right around 85psi when the engine is warm once the relief valve opens (~3000rpm and beyond). The idle pressure hangs out around 24psi.
SAVCS 04 STi
Mains: 0.0017Ē
Rods: 0.002Ē
Oil: Motul Sport 5w40
Revving to 7200rpm
External oil cooler with 200į thermostatic sandwich plate, -10 lines, no OEM cooler.
DBB turbo with restrictor on feed
Stock 10mm oil pump, no added shims
Pressure measured at galley under alternator.

I understand my mains are rather loose compared to the numbers you like to use, but seeing as I couldnít reliably get this block line bored in a timely manner, it is what it is there. However, Iíve been noticing that at WOT, Iíll get an oil pressure drop past 5000rpms, typically from ~85psi to ~75psi. Iíve verified that my electronic gauge is reading correctly with a mechanical gauge, made sure the oil cooler setup isnít restricting (shouldnít be, as -10 is about the be same ID as the block passages). KillerB pickup and baffle, so no cracked pickup. I checked the pump prior to installing for any burrs as well as loose screws on the backing plate. 5000-5100rpm happens to be the range where my AVCS goes to 0, which I believe would allow for more oil flow, potentially dropping pressure? Iím somewhat stumped here, and given the info youíve posted, this could even indicate the pump is oversized, no? Itís been mentioned that using an 11mm pump on SAVCS is too much pump and leads to aerating/pressure drop. But in certain circumstances, could even the 10mm be too large for a single AVCS engine? The pressure drop doesnít really concern me, except for on the track where that 75psi can get closer to 65psi

Last edited by brecks; Yesterday at 01:52 PM.
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Old Yesterday, 09:29 PM   #234
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Brecks,
What is your normal max RPM? Do you have any data logging capability?
It could easily be several things happening simultaneously. Your small, stock pump could be pooping out due to loose bearing clearances or it could be cavitating at higher RPM's. The centrifugal forces due to the high crankshaft rotation speeds (plus loose clearances) could also affect the oil system needs.
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Old Today, 07:13 AM   #235
KillerBMotorsport
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Quote:
Originally Posted by brecks View Post
Iím somewhat stumped here, and given the info youíve posted, this could even indicate the pump is oversized, no? Itís been mentioned that using an 11mm pump on SAVCS is too much pump and leads to aerating/pressure drop. But in certain circumstances, could even the 10mm be too large for a single AVCS engine? The pressure drop doesnít really concern me, except for on the track where that 75psi can get closer to 65psi
Can you e-mail me a log?

-10 lines are the smallest we recommend and should be fine for your RPM. Who's kit? Some have garbage fittings and/or sandwich adapters that can have funky issues with turbulence or pressure drop at certain RPMs.

DBB turbo? What's that? BB or journal? What size restrictor?

Were the pump clearances checked?

Very rare to have bypass issues on the 10mm; it's well matched to that engine. I've seen the 10mm pump work flawlessly to 10,000 RPM on these engines so I don't think it's an issue of RPM.
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