Yes, I know. You're talking about a "sprial leak path". Like I said, it's narrow and relatively long.
The numbers have been done for the leaf spring leak gaps ... thought you were in those discussions. Based on actual gap measurements, the leak could be as much as 15% of the total flow going through the filter. You were lost in the PD pump slip discussions, because you didn't really understand it fully and kept accusing me of things I never claimed. You keep thinking all health PD pumps are slipping like crazy, but that's not the case - they only slip ~15% max and the pump slip doesn't matter anyway because most start going into pressure relief at pretty low RPM (ie, they are over-sized). The pressure vs RPM graph roll-over is from pressure relief, not pump slip like you think. So I don't expect much understanding on this filter mount thread leak discussion either.
I just so happened to run some numbers through the dP calculator tool for a narrow long flow path that a non-tapered threaded joint "spiral leak" would create. If the dP across the threads was 16 PSI, the leak rate through the spiral leak path would be around 0.02 oz/min (0.00015 GPM). If there is a 16 PSI dP across a typical oil filter, it's going to be flowing at least 8-10 GPM. So the leakage through the threads compared to the total flow through the filter would be around 0.00015/8 = 0.001875% of the total flow. Better get out the thread sealant.
