Dry sump oil pressure

[sccagt1racer]

I have recently installed a are 3 stage dry sump on a ls3 engine. The oil pressure is being measured at the remote oil filter which is before the oil cooler that is located in the radiator. I am seeing 40 psi at idle and 90 at 7000 rpm's. I would like to see 70 max but is this an accurate place to measure engine oil pressure or should it be at the normal sending unit that's located in the block? The oil that's being used is 15-50 amsoil and #10 pressure lines.

[Alaskaracer]

I would measure your oil pressure at a oil galley as far away from the pump as you can. That is a more accurate representation of what your engine is seeing. Taking the reading at a remote filter is not ideal. Using the port for the factory oil pressure sending unit is also a good location.

[Warp Speed]

Oil pressure should be measured at the engine, and preferably the opposite end of oil feed entrance. By measuring at the remote filter, you are measuring pre-pressure drop of the cooler, and depending on where the sensor is in the filter housing, pre filter. This will give a false, higher reading than what the engine is seeing.
Also, the filter should be the last thing the oil goes through prior to entering the engine.

[andyf]

Where you measure the oil pressure doesn't matter when things are working okay but it might matter if things are not perfect. So if all of your lines are the correct size and there are no big restrictions to flow in the system then you can measure the pressure at any point. However, if you have restricted flow at some point then you should be measuring closer to what you really care about which is the pressure that is being fed to the bearings.

[Kevin Johnson]

A dynamic hydraulic circuit will show different values in various locations even without air entrainment. For example, when Cosworth worked on a realtime aeration measurement system they found that even block to block variations were important.

[Warp Speed]

Where you measure the oil pressure doesn't matter when things are working okay but it might matter if things are not perfect. So if all of your lines are the correct size and there are no big restrictions to flow in the system then you can measure the pressure at any point. However, if you have restricted flow at some point then you should be measuring closer to what you really care about which is the pressure that is being fed to the bearings.

Every portion (filter, cooler, fittings/lines ect.) provide a restriction. That is why it is important to measure after all of them. And, as I said in the above post, opposite end of the oil feed is optimum, as this will reflect the pressure losses through the main line, and any other systems being oiled prior.

[GARY C]

What would happen if you didn't know what the oil pressure was vs knowing what it was... how much could you gain?

[af2]

What would happen if you didn't know what the oil pressure was vs knowing what it was... how much could you gain?

???????????

[swampbuggy]

Gary, please reword your question. Mark H.

[MadBill]

Do you mean how much less power would it take to spin the pump at a still-safe minimum of say 40 psi vs. a way-high 120?
Despite what many say, per any hydraulic pump calculator I've seen it's tiny Run the numbers here, say 10 GPH @ 60 psi and be shocked: http://www.metaris.com/hp-calculator.php

[GARY C]

Gary, please reword your question. Mark H.

MadBills post covered it.

[sccagt1racer]

I am going to move the gauge sender to the back of the block. The car still had the stock pressure gauge. The back of the block reading was 65 psi at 7000 rpm 235 degrees oil temp according to the customer. I was pressed for time and lacked an adaptor for a ls3 engine so that's why I took the easy route and put the sender at the remote oil filter. Thanks for everyone's input.