Hey folks,
87 Wolfsburg 2.1, original everything
I don’t think this is a problem, I’m just wanting to learn something.
For years I’ve had VDO oil pressure and temp gauges, senders on a sandwich adaptor at the oil filter.  Start-up pressure has been just under 80, right at the top of the gauge, in any season.

As part of a recent project, I pulled the sender between the pushrod tubes and put that with the VDO sender on a tee about 7 inches forward of that port.  Now start-up pressure is about 55-57.  Would moving the sender in that manner cause a change, or that much change, in the reading?

The other change I made (burying the lead I think) is switching from Castrol 20W/50 to Mobil1 15/50 for the first time.  Does synthetic oil make that much difference in start-up pressure?