[DeTomaso] Remote oil filter setup

[Julian Kift]

If the passages are the same size, and you try to move -more- oil through them at any given moment (higher volume), doesn't that by definition have to increase the pressure?

 

>> Not necessarily, pressure is resistance to flow, so in an open pipe (with no head increase) there is no increase in pressure.

Put simply, in a reverse kind of way.... If I increase the pressure on my water pressure tank (supplying the house), I can fill a bucket with water a lot faster (higher volume).

 

>>Yes, beacuse there is no resistance to flow; P1V1 (the tank) = P2V2 (the hose) so you increase P1 at the tank and as there is no pressure change at the hose V2 increases.
 
So what is the relationship of higher volume and higher pressure and at what point do you get diminishing returns?

 

>> Depends what and how far you are pumping and line losses etc. In an engine too much pressure is as much a bad thing as too little. A hot engine should idle at around 20 psi and I've heard rule of thumb is 10 psi for every 100 HP at WOT.


To me, a "high volume" oil pump -implies- higher pressure, and... a "high pressure" oil pump -implies- higher volume.


>>On an oil pump there is an internal relief spring, dictating at what pressure the pump internally bypasses i.e. the max pressure it pumps. The high volume pump will internally bypass at a lower pressure (than a high pressure pump). The pressure it produces in the engine depends on resistance to flow i.e. leakage around bearings, frictional losses, clearances etc. 

 

>>A high pressure oil pump will require greater resistance to flow before it internally bypasses and is designed for applications where there is a lot of leakage (pressure loss) i.e. a worn engine or one designed with slide rule tolerances.

Julian

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