Read what CaptainKosmos said in a thread I started a while back.

Some info about oil pumps in general. An oil pump is a source of flow not pressure. Pressure is the cause of restriction in the fluid flow, ie you cannot have pressure if the flow isn't restricted somehow. In sense of my education (Msc in hydraulics) the hp pump in street use is pretty much nonsense atleast when referred to hot idle conditions. The pressure you have at hot idle (and in all motor operation) comes from the bearing clearances, oil passages etc. as Moper stated. Idle pressure will not rise with the HP pump because the normal idle pressure should be lower than the bypass valve crackling pressure. In some cases at hot idle the hp pump might infact raise the pressure shown in gauge but in that case, there must be some serious restrictions in the oil passages, between the pump and the gauge sensor.

So in general, the only way to raise hot idle pressure is to add more flowrate to the system which leads into hv pump. This is based on the assumption that one is using normal oil and the bypass valve isn't already open at idle.





The aproximate power needed for oil pump to run when losses are neglected is the pressure times the flowrate. If someone want's to calculate the power needed in kW the formula would be pressure (in bars) times flow rate (in liter/minute) divided by 600. So this leads to the fact that hv pump takes 25% more power from the pump shaft than stock oil pump, if the bypass valve is set at the same pressure. The equation is proportional so if you increase the maximum pressure by 20% the maximum power needed to operate the pump goes up also for 20%. For the amount of power taken, the hv pump is worse because it takes always more power than normal pump. As opposed, the hp pump takes only more power than normal pump, when the pressure level is higher than the maximum level in normal pump.

I'm not going to take any part in the discussion of what kind of pressure levels are needed for different kinds of rpms because I have no experience in that field.

You can read the whole thread here.

http://www.cuda-challenger.com/cc/index.php?topic=54050.0