Oil pressure behavior

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10-17-2003 | 10:51 PM

Imprezer

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From: Alameda, CA, USA

Car Info: 02 Black Legacy GT

Oil pressure behavior

At what pressure, is the oil pressure considered too low?
What should oil pressure be at idle?
At what pressure, is the oil pressure is considered too high?
Does oil pressure stay steady at WOT or does it fluctuate?

Anything else should one know about a very heavily modded flat four?

- Alex

10-18-2003 | 04:18 AM

Chibby Goku

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From: TDY

Car Info: Vakamon WRX

I don't know what's normal, but my car idles at about 30psi and sometimes goes as low as 20psi before it prematurely shuts off.

I haven't reached further than 100psi yet. I'm still breaking in my motor.

I'm also interested in what is normal.

10-18-2003 | 12:03 PM

Akiata

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I've got the Defi gauges so they read in some crazy reading. They read in KG/cm2. At normal operating conditions just driving around town Oil pressure is at 6 kg/cm2 or 85.3 psi. At idle it is down to 2 kg/cm2 or 28.4psi.

What about other temps and pressures. I have 6 defi gauges that monitor all of the vitals. Boost dosen't count and we know that reaching 1650ish egt temp is not good. And I know its going to vary depending on where you are reading from.

My car 02 wrx:
Oil temp = 90 deg C or 194 deg F at oil filter
Oil press = 6 kg/cm2 or 85 psi at oil filter
Oil press at idle is at 2 kg/cm2 or 28 psi
Water temp = 80 deg C or 176 deg F (rerouted the throttle body hose to just recirculate and took the temp there.
Fuel pressure = 5 kg/cm2 (I think at about 18 psi) or 71 psi.
Fuel pressure at idle is around 3.5 or 4 kg/cm2 or about 56 psi

Last edited by Akiata; 10-18-2003 at 12:06 PM.

10-19-2003 | 10:00 PM

madrex

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Joined: Apr 2003

Posts: 164

From: a van down by the river

Car Info: 03 Rex: HKS, Injen, Apexi, Perrin, Rota

i dont mean to hijack the thread here, but i'm in need of some info, and you (Akiata) seem like you might have some answers. I have an oil temp probe mounted on top of the block under the intercooler, but i am adding a pressure gauge and don't know where to put the probe? it sounds like you have both mounted at the filter, is there some reason that is a better place? what is the best way to tap into the oil there. sandwich adaptor? thanks, you can PM me if thats easier for you. later, Ben

10-20-2003 | 10:27 PM

RallySubie

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Joined: Dec 2002

Posts: 41

I am using the greddy gauges and mine also read in kg/cm2.

I've been getting about 1.5kg/m2 at idle and about 4kg/cm2 while driving. This is with the car fully warmed up.

According to the subaru manual it should be 1kg/m2 or 14psi or more at 800rpm and 3kg/cm2 or more at 5000rpm.

10-21-2003 | 01:06 PM

Kean

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Joined: Nov 2002

Posts: 261

From: So. Ca., CA USA

Car Info: 03 WRX / 08 Forester

Re: Oil pressure behavior

Quote:

Originally posted by Imprezer
At what pressure, is the oil pressure considered too low?
What should oil pressure be at idle?
At what pressure, is the oil pressure is considered too high?
Does oil pressure stay steady at WOT or does it fluctuate?

Anything else should one know about a very heavily modded flat four?

- Alex

My readings are as follows:

Engine Cold:
Cruising: ~100 PSI
Idle: ~100 PSI (drops to 90 after a minute and gradually lowers as it warms up)

Engine Fully Warm:
Cruising: settles down to around 70 - 80 PSI
Idle: settles down to around 20 - 30 PSI

As far as too low or too high? .......I would say anything that is a few PSI below 20 or significantly above 100 should be investigated.

My pressure usually stays constant @ WOT. Any fluctuations that may occur are gradual but will stay in the ranges I've described.

Hope this helps. ........btw, these readings are on a stock '03 WRX with an Omori gauge.

- Kean