Hot idle oil pressure (OP)

Average of all vehicles/all lubricants = 2.4bar

Hot idle OP by MY

MY78-85 inclusive/all lubricants = 2.5bar

MY85S2 = 2.6bar

All 928S4 models = 2.7bar

All GT and GTS models = 2.0bar

Hot idle OP by oil viscosity

All MY/all lubricants

0W-?? = 2bar

5W-?? = 2bar

10w-??= 2.4bar

15w-??= 2.5bar

20w-??= 2.6bar

??w-40= 2.1bar

??w-50=2.5bar

Hot idle OP results by percentage surveyed

2% showed below 1,5bar

11% showed 1.5 to below 2bar

34% showed 2bar

24% showed above 2.0 to 2.5bar

2% showed above 2.5 to below 3bar

20% showed 3bar

7% showed above 3bar

Therefore;

47% showed 2bar or below

44% showed above 2bar up to 3bar

91% therefore showed 3bar or less

Highest hot idle OP

3.5bar

Lowest hot idle OP

1bar (suspected error and later a a confirmed error)

Overall then about 11% were near Porsche's acceptable low point of 1.5bar

Hot OP by RPM

At 2000 rpm = 4.5bar

At 2200 rpm = 5bar

First to reach 5bar:

Reached at 1800 rpm

All respondent's engines reached at least 4bar well before 4000 rpm

Note: It is important to realise that all of these engines displaced about the same volume of lubricant at each engine revolution regardless of the OP and the lubricant's viscosity

All sythetic lubricants showed 0.3-0.5bar less than a "reasonably" close mineral lubricant. This is normal as flow is better with a synthetic lubricant due to its lessor frictional resistance. Volume is the same in each case of course

I have much more data on this issue but it simply takes too long to prepare it into a meaningful format for public consumption

I hope this is of interest

Regards
Doug Hillary