Engine oil pressure

Just looking at Franks back up monster motor dyno sheet, I noticed the oil pressure drop then pick back up. Any theories on what that might be?

Frank you have a vacuum pump on that thing?

Very good Question

Bump for Frank.........

I think on the dyno sheet it says yes it has a pump.


Jay

Yes it has a vac pump
Frank

I just checked all 11 runs and there all the same ,the oil pressure drops at the same range and then goes back up . Which I thing is due to the loose clearances that I run on the crank .0035 rods and mains ,looking at the old dyno sheets from my 600 it does the same thing and the bearings are always happy in it ! both motors also run a 5 stage peterson dry sump with a .875 pressure stage riven at 55%
Frank

It wasinteresting to see the pressure going to 80 with the juice on, I'm thinking the crank case pressure is spiking because of blow by?