ISX and Bypass Oil Filter Systems

[Hammerhead]

This is cross posted from the Shimmed Oil Pump thread as well...

So I finally got off me fat azz and finally installed my Spinner II 996 Bypass filter. Should have done this years ago, but I was told that ISX's do not produce enough oil pressure to properly propell the centrifuge. I spent some time on the phone with a very knowledgeable person from their tech support, and he said that info was wrong. A stock ISX oil pump will propell the centrifuge, but it will only run about 34-3500rpm. The optimum is 4500+, so it will work, but it's efficiency won't at its peak. Anyhoo...
As everyone here probably knows, I have shimmed my oil pump with the US$0.80 trick. I started the truck after the install was almost complete. I had the return line plumbed it, the air supply run and connected, the oil IN to the Spinner connected and the feed line ran. I did NOT connect the feed immediately. I ran the truck for about 1/2hr to achieve (close to) operating oil temp of 170*. I was running the DataLogger on Insite, so my oil pressure at 1200rpm was 47.0-47.9psi. I then shut the truck down, pulled the #5 feed port plug and installed the port fitting and connected the supply hose. Again on Insite running the DataLogger at 1200rpm my oil pressure was 45.8-46.4, giving a parasitic loss of 1.2-1.5psi of pressure loss to run a (rated) 2 gal/min Spinner bypass filter. According to the chart in the install instructions with 45psi it should be spinning the centrifuge at about 53-5400rpm and flowing about 1.7-1.8 gal/min.
Actually not as much pressure loss as I had expected it to be.
Note, this is on a fresh oil change with Rotella 15W40 and 1 gallon on Sta-Lube 80W90.