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#3194925 - 11/22/13 02:40 PM Oil Pressure Requirements
twX Offline


Registered: 12/05/08
Posts: 4
Loc: Canada
I've heard the rule of thumb that an engine should have 10 psi of oil pressure for every 1000 rpm.

The manual for my Acura Integra GS-R indicates that normal oil pressure is 50psi at 3000rpm with a warm engine, or 17 psi per 1000 rpm.

What would be the reasons for the engineers to choose the oil pump / oil grade / tolerances that result in a higher oil pressure like this? If I experience lower oil pressures (say, 12 psi per 1000rpm) due to high oil temperature at the track or a thinner grade of oil, will this cause issues? Would there be a reason that this higher oil pressure would be required?

Note that above 5000rpm or so, the pressure is pegged at 80psi due to the bypass, yet the engine revs to 8000rpm, resulting in 10psi/1000rpm. It seems to me that the higher pressure at lower rpm is not really required. Thoughts?

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#3194929 - 11/22/13 02:46 PM Re: Oil Pressure Requirements [Re: twX]
440Magnum Offline


Registered: 02/01/09
Posts: 7199
Loc: Texas
Originally Posted By: twX
I've heard the rule of thumb that an engine should have 10 psi of oil pressure for every 1000 rpm.



That's what I call "the smallblock Chevy rule." Not applicable to all engines, and certainly not to modern ones where the computer intervenes in oil pressure by controlling a variable output oil pump, for example.

Many threads on this topic already. Many engines have a very nonlinear oil pressure/rpm curve indicating that, unlike the smallblock Chevy, they are intended to run with the bypass valve open over much of the RPM range, giving a much more constant oil pressure.
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#3195004 - 11/22/13 04:32 PM Re: Oil Pressure Requirements [Re: 440Magnum]
Shannow Online   content


Registered: 12/12/02
Posts: 29862
Loc: Oz
Originally Posted By: 440Magnum
Originally Posted By: twX
I've heard the rule of thumb that an engine should have 10 psi of oil pressure for every 1000 rpm.



That's what I call "the smallblock Chevy rule." Not applicable to all engines,


Excellent, concise answer...

Look at all the "traditional" engines that it applied to...6-8 cylinders, 4-7 mains, 4-5 cam bearings, lifter lubricated top end, short timing chain and no squirters...oil pressure provdes a supply/reserve to them.

Throw in OHC, VVT, long chains, tensioners and squirters, and the manufacturer has a lot of different things that may need different oil pressures to achieve.

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#3195023 - 11/22/13 05:00 PM Re: Oil Pressure Requirements [Re: twX]
Nederlander75 Offline


Registered: 09/30/07
Posts: 886
Loc: Behind you, move over so I can...
And to bake your noodle further my rotary powered RX8 runs about 75 PSI at 3KRPM, maybe 100 or so at 5KRPM, and at redline <9KRPM I can be sitting around 135-150 PSI. Barely less with 20wt and not readably higher with 50wt.

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#3195039 - 11/22/13 05:20 PM Re: Oil Pressure Requirements [Re: twX]
Donald Offline


Registered: 03/21/04
Posts: 15594
Loc: Upstate NY
Its engine dependent. It may not be in owners manual but should be in shop manual.
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1999 Dodge Ram 2500 w/Cummins - Rotella T6 & M1


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#3195071 - 11/22/13 06:01 PM Re: Oil Pressure Requirements [Re: twX]
ammolab Offline


Registered: 01/16/06
Posts: 593
Loc: Ruidoso, NM USA
My BMW K75C motorcycle hits 68psi at 2000 RPM and holds steady until 8000 RPM. Seems like it is set up to always pump a good bit of oil through the relief valve. For years I ran 20W-50, now running 15W-40....no, I will not try 0w-20!
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#3195089 - 11/22/13 06:20 PM Re: Oil Pressure Requirements [Re: twX]
jrustles Offline


Registered: 02/24/13
Posts: 2035
Loc: Ontario, Canada
Originally Posted By: twX
I've heard the rule of thumb that an engine should have 10 psi of oil pressure for every 1000 rpm.

The manual for my Acura Integra GS-R indicates that normal oil pressure is 50psi at 3000rpm with a warm engine, or 17 psi per 1000 rpm.

What would be the reasons for the engineers to choose the oil pump / oil grade / tolerances that result in a higher oil pressure like this? If I experience lower oil pressures (say, 12 psi per 1000rpm) due to high oil temperature at the track or a thinner grade of oil, will this cause issues? Would there be a reason that this higher oil pressure would be required?

Note that above 5000rpm or so, the pressure is pegged at 80psi due to the bypass, yet the engine revs to 8000rpm, resulting in 10psi/1000rpm. It seems to me that the higher pressure at lower rpm is not really required. Thoughts?


Being a GS-R, I'd venture to say that the pressure is required. VTEC, yo
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#3195391 - 11/23/13 06:52 AM Re: Oil Pressure Requirements [Re: twX]
Garak Offline


Registered: 12/05/09
Posts: 14118
Loc: Regina, Saskatchewan, Canada
No surprise. My G specifies more than 20 psi per 1000 rpm.
_________________________
Plain, simple Garak.

2008 Infiniti G37 coupe - Mobil Delvac 1 ESP 5w-40, Wix 51358
1984 F-150 4.9L six - Quaker State GB 10w-30, Wix 51515

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