Oil Pressure Observations - Anyone else using a gauge?
 

So I finally hooked up the control unit for my gauges and installed the oil pressure gauge in the block (via the plug between the intake and AC).

At idle, I get between 750-850 kPa (108-123 PSI). That seems kinda crazy high, but whatever...

It starts dropping as it warms up, eventually settling at about:
idle: 115 kPa (16.7 PSI)
3k: 400 kPA (58 PSI)
3.5k: 450-500 kPa (65.2-72.5 PSI)
4k: 525 kPa or so

It's fairly steady from there until ~7k RPM where it starts dropping, eventually down to around 425 kPA at/near redline. That's 61.4 PSI.

Having heard the whole 10 PSI per 1,000 RPM that seems a bit low.

Also, I am running a fairly large oil cooler (19 row) which can account for some pressure loss.

So would anyone be concerned with 61 PSI near redline? Not sure if a bigger or smaller cooler would help/hurt. No cooler would increase it of course so I'm somewhat curious what people are seeing stock. Maybe I'll bypass my cooler and see whenever I have some time.

I wouldn't be concerned with 61 psi at redline. I have heard that these boxers have crazy high initial oil pressures.

"Standard" WRX oil pressures: 100PSI cold/startup, 20-40PSI idle.

EDIT: This is 5W-30. Our cars on 0W-20 would see lower pressures overall I think.

What oil are you running?

I don't think that is anything to be worried about, but the fact that it starts to drop at the top end means people that up the rpm might have issues. I wonder if any tuners have looked at the oil pressure at their increased rpm.

Currently M1 0W-20 is in the car.

Sounds low.
I think location of the plug matters in these (IIRC the plugs on top of the block yield a bit lower readings, but only by few PSIs.

Details on the plug you used?

I thought about getting the reading just after the cooler also via another sandwich plate. I do have one laying around.

I get more than enough at idle and at around 6k I get 500 or so, it's just after 7k or so that it starts dropping, almost like cavitation in a water pump at high RPM.

^^ what he said. The sensor is very short and the oil pressure bounces around a bit in that location so I am questioning the sanity of putting the sender there.. just not sure it's the best spot. After the head is nice but I'm not exactly sure where in the oil gallery that plugs leads to.. right before it dumps back to the pan? If so I'd imagine lower pressures there...

It is low but not by a lot... the question how much lower does it fall if you raise the temp of the oil to 250-280F? Daily driven it's nothing to worry about but on track it could be or get to be too low.

You may consider running an 0w-30 or 5w-30 on track (like is suggested in your owners manual)

OR

Put a spring-shim in the oil pump to bring back up the oil pressure. I have an oil cooler on my race car and I have my oil pump shimmed to bring the pressures back up so I don't have to run thicker-than-necessary oil.

Hell 0W-20 is water at 150 degrees anyways :)

I have nothing against 0w-30/5w-30 though. I have 6 qts of RP 0w-20 I might have to swap out for 5w-30.

I think first I might try to switch the sensor location to see if I'm reading from a dump tube going into the pan. The reading might be just fine earlier in the system.. I have no idea where the oil galleries route in these non-hondas :) Pressure I would guess would be lower if this is coming from the end of the system (logically - no evidence of this).

I think you're reading from a correct location (misread what you were saying earlier), just past the pump, unless Subaru completely re-did their oiling for the FA engine.