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Higher Oil Pressure after adding oil cooler?

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If have not found anything usefull yet, therefore the hope that some of you might be able to add light on the topic.

My setup
The oil cooler I use: http://www.setrab.com/products/proline/technical-specifications/slm/
The oil pressure sensor is attached to the engine via sandwich plate, in front of the adapter plate with thermostat which is in between the sandwich plate and the oil filter. The OEM heat exchanger is gone and the space used by the two plates. So the sensor is before the oil cooler and not after, which might be a reason.

Since then my readings are quite high, on the highway around 100psi on 6th gear with a bit below 3000rpm. Idle is around 35psi and I have around 114psi with 5500rpm. All these with the oil temp sensor, which is also at the sandwich plate next to the oil pressure sensore, reading around 180 - 200.

I know the place of the sensors are not ideal (had the sandwich plate with sensors already before the oil cooler), but does anyone has an explanation of this or do I have to replace the oil pressure sensor or...?
 

Grant 302

basic and well known psychic
What size is your cooler? Do you have pics of the sensor(s) installed in the sandwich plate?

Taking the pressure before the cooler should read the highest system pressures, but you also want to make sure that's not because the sensor(s) is/are blocking flow. If you look at some of 06mach1's pics in the cooler delete thread, he modified some of the sandwich plates to make sure the sensors do not restrict flow.

Looked into the SLM series and they have higher pressure drops compared to other coolers with a similar BTU/hr capacity. So your pressure to the engine should be less the delta-P shown on the charts on this page:
http://setrabusa.com/products/oilcoolers/engine/index.html
 

steveespo

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What Grant said with a caveat. The Boss oil pump has a bypass relief spring for oil pressure that is set to open at a higher pressure than a stock Coyote 302. Bosses seem to be set at 100 and GT at 85. This doesn't explain having higher oil pressure after a cooler install but it is not unreasonable that the pressure will stay close to original even with the potential drop caused by the cooler. Simply the oil pumps have reserve capacity to make up for flow restrictions. The benefits of cooler oil under high stress conditions (racing) far outweighs the loss of a few PSI. I have 75-80 psi from 2600-7500 rpm, a Boss engine will probably see 85-90 psi, both run fine.
Key is keep oil supplied to the pump and keep it cool to protect the bearings and valve springs.
Steve
 
With the 34 row air oil cooler added and the stock cooler removed I was getting 88psi running hot on the LS gauge pack (exactly the same as running stock oil cooler). Replaced the stock gauge with an Aero Meter gauge with the sensor in the sandwich plate before the oil cooler and now get 100psi running hot in that sensor location. Temporarily had both gauges installed and Stock LS gauge read 88.

My conclusion is that it's a combination of sensor/gauge calibration and location.......
 
Adding resistance to the circuit will increase pressure if the pump is beefy enough to provide the same amount of oil flow as before. Since it is geared off the engine, it definitely has the oomph for consistent flow, so pressure must increase at the output of the pump. Same principle as V = I x R (voltage is actually electrical pressure). It might not add too much idle pressure, but you should see more pressure than before. Location is part of it since pressure will decrease as you go through plumbing, the filter, etc. You really have to measure in the same spot to know if a gauge is bad.

I am not sure where the pressure is critical to measure or if you just care that you have it, and characterize what is normal so you can spot a problem quickly. I would not expect a sandwich plate to give the same pressure reading as the stock sensor if there was anything between them other than a short line.
 
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Black Boss said:
With the 34 row air oil cooler added and the stock cooler removed I was getting 88psi running hot on the LS gauge pack (exactly the same as running stock oil cooler). Replaced the stock gauge with an Aero Meter gauge with the sensor in the sandwich plate before the oil cooler and now get 100psi running hot in that sensor location. Temporarily had both gauges installed and Stock LS gauge read 88.

My conclusion is that it's a combination of sensor/gauge calibration and location.......

I am also using an Auto Meter gauge with the sensor in a port on the thermostat pre-cooler.
 

Grant 302

basic and well known psychic
Orange,
What were your pressures before you installed the cooler?

Does anybody else ever see pressures like 114 psi at 5,500?

My concern about that is the Boss relief is set at 100...so seeing 114 psi anywhere in the system could mean that there is a restriction so bad that the relief doesn't flow enough to bring system pressure back to 100. IF this is the case, it wouldn't bode well for having enough flow downstream for the engine.

To follow the electrical example, it would be like a big resistor (restrictions before the main oil galley) in series with several important components with low resistance (engine oiled parts) all connected in parallel.

I doubt the cooler itself is the problem. One item with 2 to 6 psi loss isn't going to affect anything. But the sensors could be contributing much more than that when both are installed in the same plate.
 
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Grant 302 said:
What size is your cooler? Do you have pics of the sensor(s) installed in the sandwich plate?
I have the SLM420-14PL installed, so the 14 row cooler. I also attached a picture with the sensors and the adapter plate on it, although could be a better one.
293ytyw.jpg


2012-Boss said:
Steve is right about this. I regularly see 100 psi until until the oil gets up to about 220 degrees .

That is good to hear, as I did not reach 220 degrees yet.

Grant 302 said:
Orange,
What were your pressures before you installed the cooler?

Before the setup was different:
- The sandwhich plate with both sensors was between the OEM heat exchanger and the oil filter, now the plate is between the engine and the adapter plate. The pressure beforehand I have never seen much above 100, usually 75 - 90psi when driving on the street.


The sandwhich plate I am using: 5451-01
The adapter plate in use, where the thermostat should open completly at around 192 degrees: 5453-0
http://www.isa-racing.com/images/isa/Einzelseiten/289_14.pdf

The gauges and sensors are all from http://www.aeroforcetech.com/

With the FRPP oil pan I have about 14l oil in the system (about 14.8 quarts), but that should not matter here.
 

Grant 302

basic and well known psychic
Orange,

I think that makes perfect sense now - everything sounds normal. The sensor-only sandwich plate is not restrictive at all. Changing the location of the sensors from post (stock) cooler to pre T-stat plate plus Setrab cooler makes sense for the difference in readings. I'm sure having nearly 15 qt oil capacity and no stock cooler explains the low oil temps mentioned in your first post. I'd also run a higher temp T-stat for much street use.

I'm curious what your temp and pressures will be on track!
 
Your radiator and filter cannot flow as much as the pump can give, so pressure increase.

The path after it is pretty much open so more flow than your radiator and filter would allow, so pressure decrease.

Pressure increase as flow decrease, to the limit of the pump of course.

Let's say the pump is outputting [email protected](gallon per minute) without the cooler.
Then you add the cooler, which is only flowing 8gpm.
Now the pump is [email protected]
But the line after the cooler still flow 10gpm
And since the cooler can't do 10gpm the pressure will drop back to 50 psi after the cooler

As you can see there will be different pressure depends where you measure it.
So that why I think the stock location is the best place to get a correct measure for the oil pressure.

Hopefully I make sense as is pretty hard for me to explain it easily.
All my number are for explanation only no real data.
 
As Swiss Boss is kind of saying, each component in the system will have its own flow rate at a certain pressure. But the oil flow rate is dynamic for an engine. It depends on engine rpm since the oil pump is a positive displacement pump. It will always provide a consistent volume of oil per revolution (although at high pressure there will be some leakage, it's not perfect). The electrical analogy would be a current source where the electrical pressure will increase if you increase the resistance because it is trying to force the same current, it does not care about anything else. That is why the pressure always goes up as rpm increases, too, regardless of having an oil cooler or not.

I just wanted to make my point that an increase in pressure should be expected, I just don't know how much and at what point it is unsafe. Removing the stock oil cooler will drop some pressure, but I expect it won't be a lot compared to the increase caused by the remote cooler.
 
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All of it was just because of where I placed the sensor as some have already stated. Now I moved the oil pressure sensor at the same place as the OEM pressure sensor (used for the engine light) side on the drivers side of the engine block with a T piece, and I am back at normal readings and I have the sensor there where it belongs.

Thanks for the tips and hints guys. :)
 

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