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That's increased flow without an increase of pressure. Just have to specify where there is flow and pressure, since the oil system of a car is like a complex resistor network, NOT just one resistor.
Exactly ..that's why I added the qualification
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It only makes sense if the point of measurement is different in different engines and subsequently reacts differently. Mine allegedly is read between the pump and filter. Older V8's were from the top of the engine after the mains had already tapped off of the main gallery.
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Oil pumps wear as they accrue miles. They probably begin to pump less oil per revolution as the oil heats up (internal blow-by). This is why the pressure relief may not be hit at redline on a high mile, fully warmed up engine.
Sure ..but this observational data is present in many brand new engines ...and they don't change in characteristics throughout their whole life.
My jeep 4.0, brand new, did 13 hot idle, 24 hot anywhere around 2000 rpm, and max'd out at 42 cold start. The pressure relief is above that with the OEM pump and I allegedly tap between the pump and the filter. There's nowhere else to go. I'm seeing the "main vein" here. I doubled my idle pressure (800 rpm idle) @ 2000 rpm (+/-) ..and that's where it terminates. Yet the flow must increase with rpm.
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Upramping abruptly is what my Caprice did when I bought it, until I got some miles on it. Maybe I'll make a short movie with my digital camera of hot idle oil pressure and slowly rev the engine up so you can watch the oil pressure gauge.
I know what you're saying. SBC, especially those with a hyper flare to them, do tend to have more of a range from idle to terminal pressure. But you've got a good variance in basic oil system design between one engine and another. Take off the vavle covers of your SBC and start it cold. You have Niagra Falls from the push rods. Do it on my 4.0 ..and even with a high volume oil pump (double the vane depth) ..it just kinda bleeds. My engine designers restricted the oil flow where it was deemed more needed. If I tapped pressure at different parts of the system (as you pointed out) the complexities of the design would offer different responses on the gauge in regard to flow.
The only point that I'm making (and using an inordinate amount of band width to express) is that you can't use or rely on a pressure gauge to indicate a corresponding flow in all cases. It may or may not react this way. There's too many variables and "unknowns".
I think this statement is always true.
Unless the pressure relief is breached, the oil pump will, within certain limits and conditions, provide flow in direct relation to its speed. This will result in pressure readings that may or may not indicate this directly proportional relationship.
