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Message: [QUOTE="andharri, post: 1536530, member: 31258"] The general equation describing fluid dynamics of this nature is the Hagen-Poiseuille (HP) equation: dP = 8uLQ/(pi * R^4) where dP is the pressure difference over the length of the system L, u is the dynamic viscosity (intrinsic to the oil), Q is the volumetric flow rate, and R is the pipe radius. All injectors require sufficient volume (Q) and pressure (P) of oil to operate. Generally, larger injectors require more volume (Q) than smaller injectors. As can be seen by the HP equation, providing more volume (Q) to the injectors requires EITHER larger dP, smaller L, or larger R. The pump provides the dP, which drives the volumetric rate (Q), and in practice is the single easiest way to provide more volume of oil, which is why many people opt for aftermarket HPOPs. While the pump is the easiest thing to replace, the most EFFECTIVE way to increase volumetric flow rate (Q) at a constant supplied pressure (dP) is to INCREASE the radius (R) of the pipes supplying the oil. See that in the HP equation the radius (R) is raised to the 4th power! Small differences here will net drastic differences in the flow characteristics. In the 7.3l oil supply system the oil log actually represents a larger radius pipe supplying oil to the injectors. In this region of the system the oil will flow the most efficiently and require the least pressure (dP) to move the same amount of volume (Q). Reducing the radius here will not help provide more oil to the injectors, it will further restrict the system. Reducing that volume will speed up the time it takes to FILL the log with oil, ie. after a complete oil change, but will not provide more oil to the injectors given that the system is already full. Going with the garden hose and fire hose analogy the question isn't about the volume of the hoses (oil log) but the restriction at the end (injectors). If both hoses have the same size nozzle restriction the larger hose will supply more volume. The only difference will be the time for them both to reach steady state, ie. fill up the hose. [/QUOTE]