Attention: TDR Forum Junkies 
I installed a seperate oil pressure gauge just to have a backup to the OEM gauge. Well, there are some fairly significant differences between the two.
I have an oil bypass filter so my oil pressure readings are probably somewhat lower than yours by approximately 5 - 10 pounds.
On first start of the day, cold engine they are about the same, OEM high, supplemental 90 psi. The OEM shows pressure dropping (high ~ 50 psi) after about 3 miles of 50 mph. The supplemental gauge shows the drop (85 psi - 70 psi) after about 10 miles of 50 mph then slowly drops to 60 psi and stabilizes.
The OEM gauge at idle / warm emgine shows something less than 40 psi (which is the ONLY mark on the OEM gauge except for the end limits of 0 & 110). The supplemental gauge shows 30 psi.
The OEM gauge follows rpm somewhat. The supplemental gauge follows rpm precisely.
I just did not like the choices if the OEM oil pressure goes to "0" of
1. shut it down NOW!, or
2. gamble the engine that the gauge is wrong.
Now I can cross check the supplemental and verify what is going on.
Bob Weis
I have an oil bypass filter so my oil pressure readings are probably somewhat lower than yours by approximately 5 - 10 pounds.
On first start of the day, cold engine they are about the same, OEM high, supplemental 90 psi. The OEM shows pressure dropping (high ~ 50 psi) after about 3 miles of 50 mph. The supplemental gauge shows the drop (85 psi - 70 psi) after about 10 miles of 50 mph then slowly drops to 60 psi and stabilizes.
The OEM gauge at idle / warm emgine shows something less than 40 psi (which is the ONLY mark on the OEM gauge except for the end limits of 0 & 110). The supplemental gauge shows 30 psi.
The OEM gauge follows rpm somewhat. The supplemental gauge follows rpm precisely.
I just did not like the choices if the OEM oil pressure goes to "0" of
1. shut it down NOW!, or
2. gamble the engine that the gauge is wrong.
Now I can cross check the supplemental and verify what is going on.
Bob Weis
