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Rb25/30 High Oil Pressure

PSI086

By PSI086,
in Engines & Forced Induction

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pet vl Enthusiast

pet vl

Posted
Posted

My cold oil pressure is probably 130-140 cold at idle and takes about 15-20 minutes to get down to 80 psi but as soon as to rev it its 100 again and i have troube with it pushing oil out 

Know i have drilled the head oil drains out to  9.5 -10mm from the 8 thay are as it ses to do to match the gasked i have got a 1mm restrictor in the block one blocked of a 1.2 vvt external oil feed the oil hole in the back of the head 20mm going in to the turbo drain line that is 20mm stock rb25 cam covers with -8 breathers in to a open catch can under the car i have a n1 spline drive oil pump from spool imports a asr race sump think its a 8.5 liters if this helps iam just over it thanks sorry for not putting full info

  • 3 months later...
Looney_Head Rising Star

Looney_Head

Posted
Posted

Sorry for bumping an old thread

pet vl, did you find a cause for your high oil pressure? I have a similar setup in my 25/30 but with a 25det pump and on the dyno I am seeing 8.1bar of oil pressure through a run. Oil temp is 82. I am using 10w60 edge

 

  • 2 weeks later...
Dale FZ1 Veteran

Dale FZ1

Posted
Posted
On ‎3‎/‎7‎/‎2018 at 3:12 PM, Looney_Head said:

 I have a similar setup in my 25/30 but with a 25det pump and on the dyno I am seeing 8.1bar of oil pressure through a run. Oil temp is 82. I am using 10w60 edge

 

I have three questions for this

Is the oil pump bone stock ie. original springs, no shims?

Are you relying on the OEM gauge in the dash for "accurate" pressure indication?

Have you tried a different grade of oil as per Bob's comment?

Looney_Head Rising Star

Looney_Head

Posted
Posted
On ‎19‎/‎03‎/‎2018 at 11:22 AM, Dale FZ1 said:

I have three questions for this

Is the oil pump bone stock ie. original springs, no shims? Yes bone stock brand bew RB25DET oil pump

Are you relying on the OEM gauge in the dash for "accurate" pressure indication? i have a GM 130psi oil pressure sensor feeding my Vipec ECU, will be getting a mechanical gauge to confirm the readings

Have you tried a different grade of oil as per Bob's comment? not yet, i haven't touched the car since it came off the dyno.will look into a 5w30/10w30

Hi Dale,

please see my answers underlined.

Dale FZ1 Veteran

Dale FZ1

Posted
Posted

Double check the input scaling of that sensor in the relevant ANV table, such that the ECU is correctly interpreting the voltage input.  If you had short term access to a known/good mechanical gauge it might make for good cross checking.

After that it would be well worth changing the oil grade, and do a back to back comparison for changes.

Looney_Head Rising Star

Looney_Head

Posted
Posted
On 3/21/2018 at 7:20 PM, Dale FZ1 said:

Double check the input scaling of that sensor in the relevant ANV table, such that the ECU is correctly interpreting the voltage input.  If you had short term access to a known/good mechanical gauge it might make for good cross checking.

After that it would be well worth changing the oil grade, and do a back to back comparison for changes.

thanks Dale. the sensor is the same type that i have on my fuel pressure which from injector pulses is accurate for what we calculated the engine needed.

that is the plan at the moment, try a mechanical gauge, then different oil, then if that doesn't work the sump will have to come off and see if the bypass valve is the issue.

i see other people had issues with Edge 10w60 on their RB30's (cubes) so hopefully it turns out being as simple as the wrong oil

  • Like 1
  • 5 years later...
  • 2 weeks later...
Looney_Head Rising Star

Looney_Head

Posted
Posted
On 5/12/2023 at 8:03 PM, DriftSpark said:

What happened in the end? @Looney_Head

Hi,

i ended up pulling the pump off and porting out the oil by-pass and going to a 5w/30 oil. that has fixed it. i now see 100~PSI peak

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