To check the condition of the lter element, simply note the DeltaP at idle, knowing that it represents worst case conditions.
Also note that the total flow in a return-less system is quite different, and maximum ow will occur at or near the horsepower peak.
While DeltaP could be monitored at peak horsepower on the dyno, or even by video while on track, the indicator should only be considered practically useful on a return style system.
Replacing the Element
Once pressure is relieved, the filter cup can be removed by releasing the safety latch, and spinning the cup free. The filter element is removed by pulling straight down.
Replace the old element and o-ring with new pieces, being sure to lubricate each with engine oil, grease, etc.