Oil Pressure.. too low?

[Dave-ROR]

OK so I moved the pressure sender to the sandwich plate and put temp there also so I could make sure my measurements were in the same temp range.

I also changed oil which will throw off all measurements since I thought I had some 0W-20 left but only had 5W-30. Either way I'm thinking 0W-20 is bad on track for this car anyways so I'll just create a new baseline with the 5W-30.

Today I had much better oil pressure BUT it was overcast and lightly raining. On the highway oil temps never went past 71 degrees celsius (160F). On the side roads I got it almost to 80C (176F). I didn't push it to redline but everywhere else I had 100-200 kPa more oil pressure, mostly due to oil weight I'd guess.

The Mocal oil cooler sandwich plate is full flow once the thermostat closes and partial flow until then so the cooler was still cooling down the oil during this time.

[andreyiv]

Originally Posted by Dave-ROR

...
The Mocal oil cooler sandwich plate is full flow once the thermostat closes and partial flow until then so the cooler was still cooling down the oil during this time.

That's not very good during the winter months, especially for us up north. Any idea if anyone makes a plate that cuts off all flow when cold, or if there is a way to modify the Mocal one to do that?

[Dave-ROR]

Originally Posted by andreyiv

That's not very good during the winter months, especially for us up north. Any idea if anyone makes a plate that cuts off all flow when cold, or if there is a way to modify the Mocal one to do that?

I do not know if they make one like that. I don't see any obvious way of doing so but you could just remove the plate in the winter and loop the lines. That's probably what I would so since there's no need for the cooler when it's cold.. we don't really have a winter here

[CSG Mike]

A lot of guys just put a piece of cardboard in front of the cooler... :p

[Dave-ROR]

Originally Posted by CSG Mike

A lot of guys just put a piece of cardboard in front of the cooler... :p

I thought about that but didn't want to suggest it

[Stevo22]

Originally Posted by robispec

same location you are. I want to get some stock temps and pressures and then compare how our total solution compares

Robi

Could you also measure the time required to get the oil up to operating temperature (stock vs your unit) and add that into the other comparison data you are collecting?

[Dave-ROR]

I can't wait to see Robi's testing.

As noted above I switched both sensor locations and oil weight. Most of this increase is due to the oil weight I'm sure. However, the gauge is actually STABLE now instead of bouncing often in the original location.

It's still "cold" here (~60 degrees) but on the same route today I showed the following oil pressures at approx 75C oil temp (at the sandwich plate after the oil cooler):
3k: 650 kPa (94.3 PSI)
3.5k: 680 kPa (98.6 PSI)
4k: 715 kPa (103.7 PSI)
High RPM to redline: Rock solid at about 750 kPa (108.8 PSI)

That's a massive increase from before. Again I think the pressure increase is a combination of weather (colder temps and thus colder oil) and oil weight. The stability of the reading is, IMO, related to the location of the sensor but Robi will hopefully be able to provide his experiences this weekend.

Looking forward to tracking the car next weekend instead of worrying about oil pressure

[bpracer]

Originally Posted by Dave-ROR

3k: 650 kPa (94.3 PSI)
3.5k: 680 kPa (98.6 PSI)
4k: 715 kPa (103.7 PSI)
High RPM to redline: Rock solid at about 750 kPa (108.8 PSI)

That seems to be really high oil pressure, but I don't know Subaru engines at all.

A lot of oil pressure in itself put heat the oil. Thicker oil should only have more pressure until the pump starts by-passing, unless the bypass is not effective. Cycling the bypass rapidly (and I'm assuming the pump has a bypass) will also heat oil. I wonder if this is part of the source of the high oil temps?

I wonder what part of the engine requires that much pressure?

Oh well, interesting stuff.

[rice_classic]

Oil pressure will vary a lot with temperature.

[nyc]

pressure will never change with diameter, what changes is velocity

[icemang17]

couple thoughts on oil.....

pressure varies immensely based on temp and viscosity used..... the type of oil also matters quite a bit....for exampe normal dino oil might begin to fail at 240F....vs racing synthetic oil that can be stable above 300F....

I severely overheated my Porsche 928 lemons racer.....230F plus water temps...oil pegged at 300F on the gauge with no oil cooler.....but I was running Amsoil racing 15-50 oil.....after 16 hours on track I had the oil tested.....came back perfect...no indication of overheating.....even after we fixed the cooling system oil was still consistently 275F.....

On my current race 928 I still don't have an oil cooler.....but keep in mind the stock 928 oil pan is 9 quarts

[xwd]

100+ seems a little high but this is a new motor. The turbo motors would generally see 85-95 PSI full throttle at higher RPMs.

[Sportsguy83]

@Dave-ROR, have any idea of the (looks like Torx) driver size needed to remove the Oil galley plug?

[Dave-ROR]

Originally Posted by Sportsguy83

@Dave-ROR, have any idea of the (looks like Torx) driver size needed to remove the Oil galley plug?

It's an Allen head but I don't recall the size.