Hello,
I need some advice! I am using the dry sump kit from Nova Racing with Pacet scavenge pump. Since I use the system I have problems with the oil pressure.

The symptoms are the following:
At 5000rpm the pressure hardly reaches 4 bar, whereas the engine manual states 5 bar minimum
Increasing the revs does not result in a higher pressure.
When the revs are increased to about 8000 rpm and kept constant (10s), the pressure falls down and drops below 3 bar.
The engine has been running for 12 hours in total and the symptoms have always been the same.

Here is what I have done:
1.Beginning of the year I have bought a new pressure relief valve.
2.I have tried another one too--> No change
3.I have changed grades of oil --> No change
4.I have changed the oil pressure sender --> No change
5.I bought another engine
5a. Installation of new engine with original sump --> Pressure @5000rpm is 5.2bar and increasing the revs increases the pressure (6.5bar at 8000rpm)
5b. Installation of new engine with dry sump system --> Pressure @5000rpm is 4bar and increasing the revs decreases the oil pressure just as before

From here I can only conclude that the oil pressure problem is related to the dry sump system.

Is there anybody else using this dry-sump/engine combination? What are your experiences?

What else could I do?

Is the pipe feeding the pump from the scavange tank a bit small or restricted, it sounds like the engine pump is stuggling to pull the oil in.

Alternatively the oil could be carrying air, does the scavange tank have a filter etc to seperate.

I have been on the phone with someone from Paceproducts who was also suggesting that there may be air mixed in the oil.

The tank I use comes from Caterham: https://www.caterhamparts.co.uk/popup_image.php?pID=4378&osCsid=307617d2799978c7ffa3798091bd4c36

The inlets are on the side which make the oil spin along the side of the tank. Inside there is a disc halfway up the height that has 4 20mm holes in it. For the rest no special items.

I will try to make a temporary installation with the tank very close to the sump inlet and with a bigger hose.

Anything else I can do?