How to test opening PSI for oil filter bypass?

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I recently installed an oil pressure gauge in my motor and started to take note of the oil pressures at different RPM. The oil pressure sensor is mounted using a sandwich plate between the oil filter and block on my Honda K20a2 motor. My understanding is that this gives the pressure before the filter media. I use mobil 1 15w-50 oil with a Bosch 3312 oil filter. I've noticed that the oil pressures I see are relatively high, 70psi by 2000rpm with the oil at 200-5deg. At 9000rpm I'm seeing 110psi on the gauge. Since I'm using a thicker oil along with an oil filter made for the S2000 (Honda F20c engine, it's a larger filter than the 3323 that is suggested for the k20a2), I'm concerned about whether the bypass valve is staying open more frequently than it should. I did some searching in this forum and couldn't find any info on how to go about determining what the bypass valve opening PSI is. My idea is: 1) Measure the pre filter pressure from the sandwich plate 2) Measure the post filter pressure from the main oil galley 3) subtract 2) from 1) to get a rough idea of pressure differential across oil filter media Then I can compare the measured pressure differential to bypass valve ratings to find one that will stay closed in almost all conditions when the engine is at operating temp. Is my thinking correct on that? Thanks in advance!
 
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39,806
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 Quote:
1) Measure the pre filter pressure from the sandwich plate 2) Measure the post filter pressure from the main oil galley 3) subtract 2) from 1) to get a rough idea of pressure differential across oil filter media
Yes. You can even install a pressure differential gauge between them and just read PSID. Your stock oil sender/sensor port may be downstream of the filter.
 Quote:
Then I can compare the measured pressure differential to bypass valve ratings to find one that will stay closed in almost all conditions when the engine is at operating temp.
You can compare it at any time. Cold, hot ..transition
 Quote:
Is my thinking correct on that?
Yes. Given the VTECH conditions that you'll probably encounter, you might make Superbusa's day (especially if hot oil is involved )..but ..while you're there, take time to observe the more mundane instances of high pressure differentials.
 

chunky

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 Originally Posted By: Gary Allan
Yes. You can even install a pressure differential gauge between them and just read PSID. Your stock oil sender/sensor port may be downstream of the filter. You can compare it at any time. Cold, hot ..transition Yes. Given the VTECH conditions that you'll probably encounter, you might make Superbusa's day (especially if hot oil is involved )..but ..while you're there, take time to observe the more mundane instances of high pressure differentials.
Thanks for the reply! The factory oil pressure sensor is just a switch that grounds its output when the oil pressure drops below something ridiculous like 10psi. I was planning on using the stock location to pick up post filter pressure since it's just off the main oil galley. My current gauge is a dual temp/pressure gauge with electronic sensors. I don't think the maker of my unit has a differential gauge available. I was planning to use a 2nd (less expensive) gauge hooked up to get a rough idea of the differential. So now I have some idea about how to measure the pressure differential, the question that remains is how do I find out what the bypass valve rating is for my filter? I just want to make sure that I'm staying in full flow filtration up to my redline and everywhere inbetween.
 
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Buy a filter with no bypass. OTW, I would bet the farm you're in bypass at high flow rates. I think the new dodge/mitsu/hyundai 4cyl world engine has a 25-27psig bypass. Older subaru 1.8L had no bypass (circa 1993, If I recall). AFA noticing bypass, you should see the psi delta drop at some point in the pressure/flow/ramp up. That may indicate the bypass opening. I say install a high capacity 2 stage remote filtration setup and be done with it.
 
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 Quote:
I was planning on using the stock location to pick up post filter pressure since it's just off the main oil galley.
and ..
 Quote:
My current gauge is a dual temp/pressure gauge with electronic sensors.
Use t-fittings and go dual electric or mechanical (the broader the sweep, the better the resolution). Who is the electronic pressure setup from? I tried Cyberdyne ..they used VDO sendors ..and they weren't anywhere near each other in span or range. The temp gauge was spot on with other gauges ..but not the pressure. Here's what I used most of the time. You will probably see elevated PSID at start up and during high speed transitions (shifting) ..where pump output/engine speed and the physical ability of the oil to change speeds/velocities is in conflict. ...oh...and if your volume is truly out there.
 

chunky

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 Originally Posted By: ARCOgraphite
Buy a filter with no bypass. OTW, I would bet the farm you're in bypass at high flow rates. I think the new dodge/mitsu/hyundai 4cyl world engine has a 25-27psig bypass. Older subaru 1.8L had no bypass (circa 1993, If I recall). AFA noticing bypass, you should see the psi delta drop at some point in the pressure/flow/ramp up. That may indicate the bypass opening. I say install a high capacity 2 stage remote filtration setup and be done with it.
I think the Bosch filter for the B-series Honda motors, B18C5 etc, made by Bosch have no bypass, but I'm a little hesitant to run something like that during cold startup. Eventually I may need to go with an oil cooler when this car starts to see more track time, and I'll look into a 2 stage filtration system then. Thanks!
 

chunky

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 Originally Posted By: Gary Allan
 Quote:
I was planning on using the stock location to pick up post filter pressure since it's just off the main oil galley.
and ..
 Quote:
My current gauge is a dual temp/pressure gauge with electronic sensors.
Use t-fittings and go dual electric or mechanical (the broader the sweep, the better the resolution). Who is the electronic pressure setup from? I tried Cyberdyne ..they used VDO sendors ..and they weren't anywhere near each other in span or range. The temp gauge was spot on with other gauges ..but not the pressure. Here's what I used most of the time. You will probably see elevated PSID at start up and during high speed transitions (shifting) ..where pump output/engine speed and the physical ability of the oil to change speeds/velocities is in conflict. ...oh...and if your volume is truly out there.
My pressure/temp gauge is from Spa Technique. I'm not sure who they get their pressure senders from, but the gauges are microprocessor based so the calibration tables should be pretty good once the pressure gauge is zero'd out. Mine didn't need to be zero'd out and read perfectly right out of the box. They do make a dual oil pressure gauge I believe, which would have been perfect for looking into this type of thing. They are kind of expensive though. \:\( http://www.spatechnique.com/product_pages/productdetails.cfm?id=366 I do know that the Honda K-series pumps are geared up compared to older Honda engines because of the VTC (variable timing cam) which is run off of oil pressure. I was hoping there was some way I could construct a rig to test the bypass valve threshold outside the engine, but I guess there's no easy way to do it. I was hoping I'd hear that I could cut one open and test the spring and measure the surface area of the valve to find what kind of PSI differential would be required for it to open.
 
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 Originally Posted By: chunky
I was hoping there was some way I could construct a rig to test the bypass valve threshold outside the engine, but I guess there's no easy way to do it. I was hoping I'd hear that I could cut one open and test the spring and measure the surface area of the valve to find what kind of PSI differential would be required for it to open.
Well, if you trust the specs given by the manufacturer on the bypass setting, then all you really need to do is determine how much max pressure drop there is across the filter under your most extreme driving conditions. One way to do this would be run the engine with no filter at all just long enough to collect pressure data while using some kind of oil filter "simulator can" with no guts (filter media). Once engine RPM, vs. oil pressure vs. oil temp is collected, then install the filter and re-run the same tests to collect the same RPM vs. oil press vs. oil temp data. For this test to work, the oil pressure gauge would have to be AFTER the filter. If there is a pressure drop equal or slightly more than the bypass valve psi setting spec, then the filter would be in bypass mode. So, as an example: If the oil pressure at say 5000 RPM with oil at 200 deg F was 55 psi without an oil filer, but then was 45 psi at 5000 RPM at 200 deg F then this means there is a 10 psi delta across the filter, and if the bypass spec is 8-10 psi for that filter, then it would be in bypass mode. If the pressure drop was only 5 psi (meaning 50 psi pressure reading), then it wouldn't be in bypass mode. The other way would be to have an accurate pressure gauge before and after the filter to see if the actual filter pressure drop was equal to (or slightly more than) or less than the bypass setting spec.
 
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you could make your own adapterplate with integrated bypass valving then use any preferred capacious filter with no bypass valve in it. Given you made an adapter plate already, you can prob design a plate with adjustable bypass. Then you could put a sensor or sw on it to see the opening threshold. FAF commericl cartridges, I would trust the manuf rating on the bypass. The psi delta for threshold opening value might be harder to calc than first thought, as the effective surface area may be different from side to side (aperture area vs close valve surface area on reverse)due to physical valve overlap and dynamics of such.
 
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 Quote:
I use mobil 1 15w-50 oil with a Bosch 3312 oil filter. I've noticed that the oil pressures I see are relatively high, 70psi by 2000rpm with the oil at 200-5deg. At 9000rpm I'm seeing 110psi on the gauge.
Here's what I would like you to ponder. Let me see if I can do it by example. I installed an aftermarket high volume pump in my wife's jeep at about 2500 miles. My basic belief, at that point anyway, was that virtually all wear could be neutralized by sump size, cooling, and volume. So, happy as a clam, I went about my business doing my M1 0w-30 with a remote 2 quart Permacool ..with the bigger filters. My aftermarket oil pump had a relief setting of 58psi. My 4.0 jeep only has max processing (throughput) of about 5gpm. My HV oil pump is rated @ (something like) 9gpm @ 3500 rpm (probably the limit of output due to internal port size/internal resistance). What does this mean? It means that every time I was slammed up against the relief, I was at max "room" for the oil being pumped. The rest was being shunted to relief. It also meant that I was in some variable level of elevated PSID across the filter ..up to the bypass valve setting. Now usually, even with some higher visc oils, the relief setting was never much exceeded. That is, 58psi was my peak pressure off idle. For example. Delvac 1 5w-40 would sit at 58psi over all ranges of encountered temps. RTS would push the pressure beyond it when cold. In short, I have to use a 5w-20 to process the full flow potential of the oil pump. It's mismatched with the sensible volume demands of the engine at the OEM specified viscosity. In your case, the oil pump is (assuming you haven't tinkered) at the appropriate volume for the engine demand and you're only bumping the walls perhaps with the OEM recommended viscosity. 15w-50 is taking this wall bumping beyond what it would normally include. Up to the limits of the relief port, whatever flow you're shunting with the OEM recommended viscosity, you're shunting more of it with higher viscosity fluids. IE: reduced flow.
 

chunky

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 Originally Posted By: SuperBusa
 Originally Posted By: chunky
I was hoping there was some way I could construct a rig to test the bypass valve threshold outside the engine, but I guess there's no easy way to do it. I was hoping I'd hear that I could cut one open and test the spring and measure the surface area of the valve to find what kind of PSI differential would be required for it to open.
Well, if you trust the specs given by the manufacturer on the bypass setting, then all you really need to do is determine how much max pressure drop there is across the filter under your most extreme driving conditions. One way to do this would be run the engine with no filter at all just long enough to collect pressure data while using some kind of oil filter "simulator can" with no guts (filter media). Once engine RPM, vs. oil pressure vs. oil temp is collected, then install the filter and re-run the same tests to collect the same RPM vs. oil press vs. oil temp data. For this test to work, the oil pressure gauge would have to be AFTER the filter. If there is a pressure drop equal or slightly more than the bypass valve psi setting spec, then the filter would be in bypass mode. So, as an example: If the oil pressure at say 5000 RPM with oil at 200 deg F was 55 psi without an oil filer, but then was 45 psi at 5000 RPM at 200 deg F then this means there is a 10 psi delta across the filter, and if the bypass spec is 8-10 psi for that filter, then it would be in bypass mode. If the pressure drop was only 5 psi (meaning 50 psi pressure reading), then it wouldn't be in bypass mode. The other way would be to have an accurate pressure gauge before and after the filter to see if the actual filter pressure drop was equal to (or slightly more than) or less than the bypass setting spec.
Do manufacturers publish the bypass valve opening PSI?
 

chunky

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 Originally Posted By: ARCOgraphite
you could make your own adapterplate with integrated bypass valving then use any preferred capacious filter with no bypass valve in it. Given you made an adapter plate already, you can prob design a plate with adjustable bypass. Then you could put a sensor or sw on it to see the opening threshold. FAF commericl cartridges, I would trust the manuf rating on the bypass. The psi delta for threshold opening value might be harder to calc than first thought, as the effective surface area may be different from side to side (aperture area vs close valve surface area on reverse)due to physical valve overlap and dynamics of such.
You give me too much credit. I have a pre-made adapter plate from Greddy. It was cheap and available, so I didn't bother with having a custom one made.
 

chunky

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 Originally Posted By: Gary Allan
 Quote:
I use mobil 1 15w-50 oil with a Bosch 3312 oil filter. I've noticed that the oil pressures I see are relatively high, 70psi by 2000rpm with the oil at 200-5deg. At 9000rpm I'm seeing 110psi on the gauge.
Here's what I would like you to ponder. Let me see if I can do it by example. I installed an aftermarket high volume pump in my wife's jeep at about 2500 miles. My basic belief, at that point anyway, was that virtually all wear could be neutralized by sump size, cooling, and volume. So, happy as a clam, I went about my business doing my M1 0w-30 with a remote 2 quart Permacool ..with the bigger filters. My aftermarket oil pump had a relief setting of 58psi. My 4.0 jeep only has max processing (throughput) of about 5gpm. My HV oil pump is rated @ (something like) 9gpm @ 3500 rpm (probably the limit of output due to internal port size/internal resistance). What does this mean? It means that every time I was slammed up against the relief, I was at max "room" for the oil being pumped. The rest was being shunted to relief. It also meant that I was in some variable level of elevated PSID across the filter ..up to the bypass valve setting. Now usually, even with some higher visc oils, the relief setting was never much exceeded. That is, 58psi was my peak pressure off idle. For example. Delvac 1 5w-40 would sit at 58psi over all ranges of encountered temps. RTS would push the pressure beyond it when cold. In short, I have to use a 5w-20 to process the full flow potential of the oil pump. It's mismatched with the sensible volume demands of the engine at the OEM specified viscosity. In your case, the oil pump is (assuming you haven't tinkered) at the appropriate volume for the engine demand and you're only bumping the walls perhaps with the OEM recommended viscosity. 15w-50 is taking this wall bumping beyond what it would normally include. Up to the limits of the relief port, whatever flow you're shunting with the OEM recommended viscosity, you're shunting more of it with higher viscosity fluids. IE: reduced flow.
I've thought about this before. With a higher viscosity oil in a given system, you reach a given pressure with less net flow versus a lower viscosity oil in the otherwise identical system. The factory motor has oil squirters installed. However, I'm using forged pistons in my motor, so the oil squirters have been removed, reducing the flow requirements. The oil pump and oil pump relief spring are stock, but I have considered swapping the spring in favor of a stiffer one to raise the oil pump's internal bypass PSI. That leaves the filter's bypass valve as the last variable. I want to get some idea of what's happening with the filter bypass before I start tweaking with the oil pump's relief spring. If I raise the oil pump's output PSI, which is already somewhat elevated due to the heavier oil I run, then I'll just worsen my filtration problem if I'm already exceeding the oil filter's bypass threshold. Right now, I'm reasonably confident that on my normal commute the bypass isn't opening. The oil doesn't turn black until >1000mi. I've also just sent out an oil sample for analysis that will give me a better idea of how/poorly the filtration is working on this motor (which is only 2 oil changes old). I'm just worried about when I go to the track and spend more time in the upper RPM range with a lot of transient changes. That's when I think I'm likely to run into situations that will open the bypass valve in the filter for unhealthy durations of time. Looks like I need to get a 2nd pressure sensor and write some datalogging software for my microcontroller and then plot the results to find the peak PSID pre/post filter. Hopefully Bosch can tell me what the PSI rating on the bypass valve is for the filter I use. Otherwise, I'm going to have to get clever about trying to figure out what the filter's bypass PSI is. Thanks for all the replies guys. This has certainly helped to give me some direction. :)
 

chunky

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Alright, so after doing some research, I looked on Fram's website which lists bypass valve specs for all their filters. I found their compatible part to the Bosch 3312, PH9688, and it's rated at 9-15psi. The filter that is OEM for my motor, PH7317, is rated at 13psi. The S2000 filter is a larger diameter filter, 3.02" diameter vs. 2.69", but a little shorter, 3.08" vs. 3.47". I also called Bosch's customer line and they're supposed to be calling me back with the information on the bypass valve spec for the 3312 filter. This will give me some ballpark idea of the kind of pressure drop across the filter media required to open the bypass. Then I can put together a dual gauge setup to see what my max pressure drop across the filter is. :)
 
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 Originally Posted By: chunky
I've thought about this before. With a higher viscosity oil in a given system, you reach a given pressure with less net flow versus a lower viscosity oil in the otherwise identical system. The factory motor has oil squirters installed. However, I'm using forged pistons in my motor, so the oil squirters have been removed, reducing the flow requirements. The oil pump and oil pump relief spring are stock, but I have considered swapping the spring in favor of a stiffer one to raise the oil pump's internal bypass PSI. That leaves the filter's bypass valve as the last variable.
From what you have said earlier in your very first post ... : "I use mobil 1 15w-50 oil with a Bosch 3312 oil filter. I've noticed that the oil pressures I see are relatively high, 70psi by 2000rpm with the oil at 200-5deg. At 9000rpm I'm seeing 110psi on the gauge." ... it seems that the 110 psi you're seeing on your oil pressure gauge is probably above what the oil pump's OEM/stock relief pressure is actually set to. My guess is that with the thicker oil, and the pretty high RPM that the oil pump is in full relief, BUT the relief circuit is undersized/restrictive and can not accurately regulate the oil pressure to the engine. This means that there is more oil volume going to the filter/engine circuit because of inefficient relief/shunting of excess oil pump volume back to the engine sump. This also means that the filter bypass may be operating more under these conditions then if the oil pump could regulate the pressure to the actual relief setting. The more pressure the pump puts out, the more volume will be flowing down the fixed resistance filter/engine oiling circuit. If you modify your oil pump to produce even higher output pressure then you see now, then this will also increase the chance that the filter will be in bypass unless you use a filter with a higher bypass valve psi setting as the filter's PSI delta will become higher as oil flow volume increases. This is exactly why Subaru uses a 23 psi bypass setting spec on their high volume oil pumped engines.
 
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 Quote:
I want to get some idea of what's happening with the filter bypass before I start tweaking with the oil pump's relief spring. If I raise the oil pump's output PSI, which is already somewhat elevated due to the heavier oil I run, then I'll just worsen my filtration problem if I'm already exceeding the oil filter's bypass threshold.
Except due to ultra high volume (which your oil pump may put out stock) the only time you see PSID is when the oil pump is in relief. Stated another way. Whenever your oil pump is in relief, you're at elevated PSID across the filter. When you are not, and not at some really high volume, the filter is invisible. Take any conduit (highway, corridor, pipe,) ..any one where there are transitions from wider to narrower..back to wider again...etc..etc. The intermediate velocity will change, but not the mean. When the pump isn't in relief, and is of sensible efficiency, you've got one unified flow that doesn't have any choice where it goes. The pressure from the resistance of the engine is very big ..and the filter extremely small (in most cases). Now when you're in relief, the physics change and you're now on a pressure applied to a resistance = flow (like a water faucet/wall outlet). Out of relief you're in a flow over a resistance = pressure (5gpm through a 1" pipe vs. 5gpm through a 1/2" pipe - 5gpm=5gpm the difference is pressure ..exchange viscosity for the different size pipes).
 
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 Originally Posted By: Gary Allan
 Quote:
I want to get some idea of what's happening with the filter bypass before I start tweaking with the oil pump's relief spring. If I raise the oil pump's output PSI, which is already somewhat elevated due to the heavier oil I run, then I'll just worsen my filtration problem if I'm already exceeding the oil filter's bypass threshold.
Except due to ultra high volume (which your oil pump may put out stock) the only time you see PSID is when the oil pump is in relief. Stated another way. Whenever your oil pump is in relief, you're at elevated PSID across the filter. When you are not, and not at some really high volume, the filter is invisible.
Well, not really "invisible". What really happens is that the PSID across the filter increases along with the oil volume going through it. At zero oil flow there is zero filter PSID. At max oil flow there is max filter PSID. When the oil flow is between zero and max, there is some corresponding filter PSID between zero and the possible maximum. When the oil pump outlet pressure hits relief, then that is (theoretically) the max possible oil pressure on the filter/engine circuit ... and point of max oil volume flow and max PSID across the filter and engine flow circuits. As I mentioned above though ... if you are seeing oil pump outlet pressures way above the relief psi setting, then the relief valve/circuit on the pump is too inefficient for the volume the pump it putting out. If you use an oil filter that is pretty restrictive and has a pretty low bypass setting on an engine that has a high volume oil pump, then that filter could certainly go into bypass way before the oil pump goes into relief mode.
 

chunky

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 Originally Posted By: SuperBusa
From what you have said earlier in your very first post ... : "I use mobil 1 15w-50 oil with a Bosch 3312 oil filter. I've noticed that the oil pressures I see are relatively high, 70psi by 2000rpm with the oil at 200-5deg. At 9000rpm I'm seeing 110psi on the gauge." ... it seems that the 110 psi you're seeing on your oil pressure gauge is probably above what the oil pump's OEM/stock relief pressure is actually set to. My guess is that with the thicker oil, and the pretty high RPM that the oil pump is in full relief, BUT the relief circuit is undersized/restrictive and can not accurately regulate the oil pressure to the engine. This means that there is more oil volume going to the filter/engine circuit because of inefficient relief/shunting of excess oil pump volume back to the engine sump. This also means that the filter bypass may be operating more under these conditions then if the oil pump could regulate the pressure to the actual relief setting. The more pressure the pump puts out, the more volume will be flowing down the fixed resistance filter/engine oiling circuit. If you modify your oil pump to produce even higher output pressure then you see now, then this will also increase the chance that the filter will be in bypass unless you use a filter with a higher bypass valve psi setting as the filter's PSI delta will become higher as oil flow volume increases. This is exactly why Subaru uses a 23 psi bypass setting spec on their high volume oil pumped engines.
Good point. The bypass in the oil pump opens around 90-95psi. This is my best guess since the oil pressure rises with RPM until about 90-95psi and then holds steady, for the most part, independent of RPM. Obviously at higher revs, the oil pressure again begins to rise beyond 90-95psi. What you've pointed out is exactly why I want to get the bypass situation figured out first. I need to know if the filter is in bypass. If not, then I'm probably ok with the current setup (not likely). If it is (likely), then the question becomes how do I keep the filter from going into bypass? At that point, I can start to evaluate whether I need to modify the pump's internal relief, find a different oil filter part, etc. Some may question why I don't just run a thinner oil to bring oil pressure down. The reason why I run the 15w-50 is because this is a motor with aftermarket forged pistons which are installed with a relatively loose piston to wall. A thicker film is beneficial. Also, because the cams turn such high rpm and do not have forced oiling at the roller rocker/cam lobe interface, a thicker oil is beneficial with the high seat pressure valve springs I have. Thinner oils are more likely to sling off the cam/roller rocker. Anyhow, it's quite possible that the oil volume from my oil pump is greater than what is required by my motor since I do not have the oil squirters installed. As you pointed out, this results in the oil pump's internal relief being overwhelmed, which results in pressure buildup pre-filter, which results in the bypass opening more often than it should. I'm leaning towards trying to find a filter that has a higher psi bypass as it would be easier than modding the oil pump. The factory manual specifies normal oil pressure as 80psi as measured from the stock oil pressure switch location. If I use a filter with a higher psi bypass, I'll just have to make sure that I'm still getting 80psi or better at the stock location. I did some more poking around on the Fram website and found that the Acura NSX filter has a 31psi bypass. Some models of the Legend and TL also shared this filter part. Only problem is that the thread size is 22x1.5 and my filter is 20x1.5. \:\(
 
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It appears that if the engine drill post filter is restrictive enough to limit max volume flow, the PSID may remain minimal even with a large operating pressure at high rpm. What's the can burst on the bosch?
 
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