In the latest engine failure thread (https://www.718forum.com/threads/engine-failure-recourse.30533) @almazing observed much higher oil pressure in the new motor than in the old (https://www.718forum.com/posts/407763/)
In the “old days” oil pressure was simple for a Porsche: 5 BAR pressure by ~3k RPM. 5 BAR pressure at cold start up (due to pressure being a measurement of viscosity) with pressure dropping to 1.5 to 2 BAR at idle at operating temp.
1 BAR = 14.5 PSI
5 BAR = 72.5 PSI.
However, in our 9A2-family engines we are “gifted” with a software-controlled variable displacement oil pump, so, even if we knew without a doubt that the MFD isn’t lying, there’s no super-simple way to determine if oil pressure is appropriate for conditions.
The question:
Does anyone have objective knowledge of the load/rpm/temperature space that serves as the software requirement for that which controls the pump? Has anyone run across a WSM section that describes it (for those with WSM access?)
I made some observations this morning in our Spyder. I did see > 50 PSI oil pressure at ~215°F oil temperature at mid-range RPM. But, only under some load. I didn’t make WOT to redline observations. Under cruise conditions oil pressure is in the 2 to 3 BAR range (say 30 to 40 PSI) with some trivial regard for RPM.
Pressure is demonstrably related to load and RPM. I assume temperature as well, since at lower oil temp more pressure is required to achieve a flow target.
In the “old days” oil pressure was simple for a Porsche: 5 BAR pressure by ~3k RPM. 5 BAR pressure at cold start up (due to pressure being a measurement of viscosity) with pressure dropping to 1.5 to 2 BAR at idle at operating temp.
1 BAR = 14.5 PSI
5 BAR = 72.5 PSI.
However, in our 9A2-family engines we are “gifted” with a software-controlled variable displacement oil pump, so, even if we knew without a doubt that the MFD isn’t lying, there’s no super-simple way to determine if oil pressure is appropriate for conditions.
The question:
Does anyone have objective knowledge of the load/rpm/temperature space that serves as the software requirement for that which controls the pump? Has anyone run across a WSM section that describes it (for those with WSM access?)
I made some observations this morning in our Spyder. I did see > 50 PSI oil pressure at ~215°F oil temperature at mid-range RPM. But, only under some load. I didn’t make WOT to redline observations. Under cruise conditions oil pressure is in the 2 to 3 BAR range (say 30 to 40 PSI) with some trivial regard for RPM.
Pressure is demonstrably related to load and RPM. I assume temperature as well, since at lower oil temp more pressure is required to achieve a flow target.
