Oil PSI vs. Volume
Oil PSI vs. Volume Could someone please tell me how psi and volume correlates? What I am trying to figure out is..if you have good oil psi are you garunteed to be ok?..Or could you have good psi and poor volume? If volume increases does psi also? 
to the OP, I think what you are referring to is the "ported/blueprinted pumps" that alot of shops sell? If so, what they do is bore the oil pump out, check the gears on the pump, and then shim the spring on the pump that regulates the oil pressure. After the pump has been bored, you have a chance of running lower than stock oil Psi due to the porting. They just shim the pump spring back up to get it within spec. Also, having too much PSi can be detrimental.
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tim is right, its how tight or sloppy the clearances in the engine are, that control oil pressure, the tighter the passages in the engine and bearings, the higher the oil pressure. race engines are set up looser for less friction and they need high volume oil pumps and bigger oil pans to keep the oil flowing.
Higher pressure will result in more flow.
Higher volume will result in more flow.
Teching In
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From: Minnesota
Or could you have good psi and poor volume?
Yes. Some people will see they have poor oil pressure and use high viscosity oils. Sure it gets the pressure up (thick oil has more resistance to flow), but it doesn't do anything for volume.
If volume increases does psi also?
Yes, if everything else stays the same. The only way to get more pressure would be to add more flow. An oil pump creates FLOW, not pressure. Resistance to flow causes pressure.
Yes. Some people will see they have poor oil pressure and use high viscosity oils. Sure it gets the pressure up (thick oil has more resistance to flow), but it doesn't do anything for volume.
If volume increases does psi also?
Yes, if everything else stays the same. The only way to get more pressure would be to add more flow. An oil pump creates FLOW, not pressure. Resistance to flow causes pressure.
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Verdad Gallardo What happens to your water hose when you put your thumb over the end or put a sprayer on? It sprays further(pressure goes up) but not as much comes out, smaller stream(volume goes down) and vice versa.
Notice this fuel pump spec chart from Aeromotive, as pressure goes up, volume from the pump goes down, it is the same for any liquid under pressure
Any fluid pump has the same laws applied to it.
David
Last edited by FASTFATBOY; Nov 27, 2007 at 06:12 PM.
Look up pump effeciency curves.
making generic statements like "more pressure = less flow" can get you into trouble. The pump is going to have a specific head that it works best with and that is not the least pressure.
making generic statements like "more pressure = less flow" can get you into trouble. The pump is going to have a specific head that it works best with and that is not the least pressure.
On The Tree
Joined: Nov 2004
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I learned this growing up in a hydraulic shop, to get pressure a restriction HAS to be put in front of the flow, lowering volume.
What happens to your water hose when you put your thumb over the end or put a sprayer on? It sprays further(pressure goes up) but not as much comes out, smaller stream(volume goes down) and vice versa.
Notice this fuel pump spec chart from Aeromotive, as pressure goes up, volume from the pump goes down, it is the same for any liquid under pressure
Any fluid pump has the same laws applied to it.
David
What happens to your water hose when you put your thumb over the end or put a sprayer on? It sprays further(pressure goes up) but not as much comes out, smaller stream(volume goes down) and vice versa.
Notice this fuel pump spec chart from Aeromotive, as pressure goes up, volume from the pump goes down, it is the same for any liquid under pressure
Any fluid pump has the same laws applied to it.
David
the electric fuel pump uses an electric motor to power the fuel pump. U load any electric motor up it will slow down(=less pumping volume). Now the engine oil pump runs at engine speed. U put a bigger oil pump in your engine it will pump more oil thru the engine which will increase oil pressure.U put a smaller pump in your engine u will pump less volume therefore you will have less pressure.
Doesnt matter what is pushing the fluid, if volume goes up, pressure goes down and vice versa.
I think of it this way...if the same pump were used in an engine 1 and you had .009 bearing clearance(LARGE!) you would have low pressure and LOTS of volume...it would almost freeflow.
In engine 2 same pump with bearing clearance of .0025(what it should be on a small block Chevy) it would restrict the flow(less volume) making more pressure.
David
Last edited by FASTFATBOY; Nov 28, 2007 at 07:43 PM.
Here you go, this is a first law of thermodynamics problem.
This will help
http://www.grc.nasa.gov/WWW/K-12/airplane/thermo1f.html
This will help
http://www.grc.nasa.gov/WWW/K-12/airplane/thermo1f.html
Here you go, this is a first law of thermodynamics problem.
This will help
http://www.grc.nasa.gov/WWW/K-12/airplane/thermo1f.html
This will help
http://www.grc.nasa.gov/WWW/K-12/airplane/thermo1f.html
Another example: WHy is it bad when you have high blood pressure? Because the volume of blood is not getting where it should. The veins are restricted.
David
On The Tree
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Doesnt matter what is pushing the fluid, if volume goes up, pressure goes down and vice versa.
I think of it this way...if the same pump were used in an engine 1 and you had .009 bearing clearance(LARGE!) you would have low pressure and LOTS of volume...it would almost freeflow.
In engine 2 same pump with bearing clearance of .0025(what it should be on a small block Chevy) it would restrict the flow(less volume) making more pressure.
David
I think of it this way...if the same pump were used in an engine 1 and you had .009 bearing clearance(LARGE!) you would have low pressure and LOTS of volume...it would almost freeflow.
In engine 2 same pump with bearing clearance of .0025(what it should be on a small block Chevy) it would restrict the flow(less volume) making more pressure.
David
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1. if you maintain the same pipe/tube/line size and increase pressure, you will get more volume of fuel.
2. if you maintain the same pressure and increase line/tube/pipe size, you will also get more volume of fuel.
2. if you maintain the same pressure and increase line/tube/pipe size, you will also get more volume of fuel.
The spring in the oil pump does not increase pressure. It is an overpressure regulator. If the pressure goes up high enough to overcome the spring tension the piston is moved and the exeess pressure it bled off. This could be due to a restriction on the oil galley or a dirt oil filter for example. Lack of maintenance or maybe an engine failure of some sort.
I always thought of it like when you put your thumb over the end of a hose to water something.
What your doing is decreasing the size of the exit right? So when the size of the exit decreases, and the flow to the exit remains the same, the pressure at the exit must increase, hence the spray. This does not mean that the "flow" is better. Ideally, for better "flow", which is how much actual (item) you are moving, you would want to make everything larger and still maintain the "pressure" needed without making the exit smaller. If you just increased the size of the "hose" then the pressure would drop because there is less resistance to the movement of the item through it. Alternatively, if you increase pressure, the flow (amout of item (which does not compress) moving through a confined space in a given time) MUST increase if the hose size stays the same. In a motor if you hog out the oil pump and shim the spring, you are allowing the motor to move MORE liquid (oil) through the same size area, which SHOULD increase the oil pressure. Right? So if oil pressure goes up in this manner (more flow into the same size area requires a higher pressure) then how is it detrimental? (all that for a question)
What your doing is decreasing the size of the exit right? So when the size of the exit decreases, and the flow to the exit remains the same, the pressure at the exit must increase, hence the spray. This does not mean that the "flow" is better. Ideally, for better "flow", which is how much actual (item) you are moving, you would want to make everything larger and still maintain the "pressure" needed without making the exit smaller. If you just increased the size of the "hose" then the pressure would drop because there is less resistance to the movement of the item through it. Alternatively, if you increase pressure, the flow (amout of item (which does not compress) moving through a confined space in a given time) MUST increase if the hose size stays the same. In a motor if you hog out the oil pump and shim the spring, you are allowing the motor to move MORE liquid (oil) through the same size area, which SHOULD increase the oil pressure. Right? So if oil pressure goes up in this manner (more flow into the same size area requires a higher pressure) then how is it detrimental? (all that for a question)