Anytime a fluid flows it is subject to pressure, and there is less pressure on the end of the hose the fluid is flowing to, (gravity flow excluded.) The psi in a garden hose is significantly reduced, but still there. Even water in a pond is subject to atmospheric pressure of 14.7 per Ken's post:
quote:
It takes about a 2-1/2 foot vertical column of oil to equal 1 psi. In any case, the additional 3" drop of oil in the hose down to the pan would exactly equal entering the oil pan 3" under the oil surface.
A 33' tall column of water exerts one atmosphere of pressure...14.7 psi... Ken
Water in a vertical column is subject to atmosphere pressure of 14.7 plus 1 psi for every
2 1/2 feet of column. At 100' the pressure at the bottom of the column (near the pump) is 54.7 psi. If the pump creates a pressure of 55 psi at the bottom of the column the difference is 55-54.7 or .3 psi to move the water.
In both the sandwich adapter and the oil pan the oil is at 14.7 atmospheric pressure. If the pump creates a pressure of 55 psi the difference is 55 - 14.7 or 40.3 psi. The difference between the two will be the resistance designed into each. Since the DB and sandwich adapter have more hardware and oil galleys at the end, the resistance will be higher and the pressure will go up accordingly.
Pressure in the sandwich adapter will be created by both the return oil flowing from the by-pass (10%) and the return oil flowing from the full flow filter (90%). That pressure will be less than 55 psi. The pressure in a hose to the oil pan will be even more less than 55 psi due to lack of resistance. End of 5 psi examples.
Generally speaking, since there is significant resistance in the sandwich adapter/by-pass, one of two things will happen. Either flow will slow, or pressure will increase, as a result of that resistance. In the case of a cold engine start, or high rpm, you can see pressure increase on your gage.
For the flow to be reduced one of two things need to happen. Either the pump is slowed down, or the oil leaks out of the system. In an electronic controlled engine the computer increases fuel to maintain rpm. We do know that there is a slight amount of oil that sneaks past the gears of an engine oil pump, but believe that amount not to be significant.
The only remaining leak of oil would be the by-pass safety system in the engine. I don't know the number, but I thought it was high, as it is designed to protect the oil filter from damage, not to control oil flow.
[ December 27, 2003, 07:48 PM: Message edited by: greencrew ]