Oil pressure question

[axis]

Since I've gotten my oil pressure gauge installed I've done some research to find out what the normal operating pressure should be and from what I've seen, people say that as long as it doesn't go below 18 psi then it should be fine.

Well, when I first start the car up (when it's cold) it reads around 80psi and once driven, fluctuates between 60-100psi. BUT once the car is completely warmed up and I'm at idle the car will hover around 18-20psi and even dip to 16psi...often.

Now, I've also read that depending on where my sensor is located that can have an effect on the reading. My sensor is located on the rear galley plug on top of the enging (close to the turbo). The factory sensor is up forward behind the alternator.

My question is, how bad is it that my car drops to 16psi? I've looked for leaks and haven't spotted any. Thanks in advance.

[Berge56]

That is the prefered location for the oil pressure sensor, That is where I have my defi oil pressure sensor. When I start my wrx, the oil pressure is around 100 psi, once the car is warm it sits between 65-80 psi under throttle. At idle it usually sits around 20 psi, so I would say your ok at idle.

[Nrw]

That's what mine does as well. I've always assumed it was fine :dunno:, same location as well.

[RCKSTR]

That is the prefered location for the oil pressure sensor, That is where I have my defi oil pressure sensor. When I start my wrx, the oil pressure is around 100 psi, once the car is warm it sits between 65-80 psi under throttle. At idle it usually sits around 20 psi, so I would say your ok at idle.

I get the same exact readings but my sensor is on top of the motor, to the left of the throttle body if you're looking from the front of the car. I'm running an autometer gauge.

[Berge56]

I get the same exact readings but my sensor is on top of the motor, to the left of the throttle body if you're looking from the front of the car. I'm running an autometer gauge.

That is the rear oil gallery plug by the turbo. :palm:

[axis]

You guys don't think 16psi is too low? How low IS too low?

[yaya]

It's normal.

When does it dip? Mine dips as my idle drops when I come to a stop.

[axis]

It's normal.

When does it dip? Mine dips as my idle drops when I come to a stop.

Samesies. When at idle when it's up to temp and when I come to a stop. I was just affraid that 16psi was too low.

[Psychoreo]

Oil pressure gauges only serve one purpose. To make you utterly paranoid that your engine is going to explode.

[Psychoreo]

You guys don't think 16psi is too low? How low IS too low?

My prosport, once fully warm after driving and back down to idle, would read 7psi. But then again, I've always suspected my gauge was off and since it's now permanently at 100+psi I'm gonna go with that.

[axis]

My prosport, once fully warm after driving and back down to idle, would read 7psi. But then again, I've always suspected my gauge was off and since it's now permanently at 100+psi I'm gonna go with that.

Haha, I have not heard very good things about Prosport gauges. I'm hoping that these STRI gauges perform a little bit better.:cool:

[Nrw]

my prosports are holding up so far.. I guess I'll see how long they last lol

[SicRedGt]

16psi is fine. IIRC, the light comes on at 2psi! :eek:

That qualifies as an idiot light for sure. :lol:

My engine building experience; I was always taught 10 psi for every 1000 rpm.

[RCKSTR]

That is the rear oil gallery plug by the turbo. :palm:

I thought you meant by the oil feed line...

[Berge56]

I was always taught 10 psi for every 1000 rpm.

Now that you say that, I recall hearing that as well.

I thought you meant by the oil feed line...

:lol: its okay buddy. I usually get confused easily as well.

[yaya]

16psi is fine. IIRC, the light comes on at 2psi! :eek:


Yep. If that comes on... :hide:

[boxer3maine]

Oil pressure gauges only serve one purpose. To make you utterly paranoid that your engine is going to explode.

it can determine when subarus reliefs are open.
when the gauge reads low, it is actually quite high volume..(good chance of it)
a real low and reliefs open are hard to determine... gauge won't help there. I find subarus design is big enough that reliefs open is the number 1 source of low. Else the engine is going to be rapping to a real low oil pressure. Don't need gauge for much then.
other than that, quibbling over a pound or two different from the book is not much.

Even changing the oil changes the number.

and they tend to make a whirling noise at times at the pump.. knowing what the pressure is hanging onto is peace of mind.

[fbodydude53]

My engine building experience; I was always taught 10 psi for every 1000 rpm.

This is what I have heard as well, I know thats fine for small blocks, do subies need higher oil pressure?? :dunno:

Oil pressure gauges only serve one purpose. To make you utterly paranoid that your engine is going to explode.

:rofl:

[SicRedGt]

This is what I have heard as well, I know thats fine for small blocks, do subies need higher oil pressure?? :dunno:


I would venture to say yes. Especially with active cam timing engines.

[AExiOn]

It's normal.

When does it dip? Mine dips as myc idle drops when I come to a stop.

my van does this also.... is it sad that my basemodel astro van came with one stock.. :unamused:

Startup reads high. 80s

Idle it starts to drop to 40. After a long drive. Coming to a stop it drops to 20, rev or when I start driving again it holds at 40

[Kojak77]

Mine does the exact same thing.

Cold start is over 100psi ( my Prosport gauge only goes to 100, so I don't know wtf it's actually reading after that)

Then highway is around 80psi.

After a nice beat run or long trip, idle is around 16-20psi fluctuating.

My sender is remote mounted, using the galley plug under the alternator.

[Hero]

I get over 100 cold - 80-95 driving and 20-25 at warmed up idle (around 750rpm) - sensor at the filter

[Evoeater]

I see:
100+psi cold idle
70-85psi cruising
32psi warm idle
28psi totally heat soaked idle

Read from Prosport gauge on a fully built block/heads with idle set at 950rpms

[axis]

I see:
100+psi cold idle
70-85psi cruising
32psi warm idle
28psi totally heat soaked idle

Read from Prosport gauge on a fully built block/heads with idle set at 950rpms

Damn, you've got WAYYYY higher pressure than I do.

[Psychoreo]

Damn, you've got WAYYYY higher pressure than I do.


Built motor/closer bearing tolerances/larger pump?

[axis]

Built motor/closer bearing tolerances/larger pump?

That'd probably make sense, huh?

[SicRedGt]

Built motor/closer bearing tolerances/larger pump?


Thicker oil?

[Antihero]

For the record, I wouldn't trust anything a ProSport gauge says. Especially since I've been through 2 boost gauges in a year.

16psi is fine at idle.