Richard Sohn OMP (MOP) Adapter
#376
...
Yes, there is a relationship between flow and pressure in a normal system that is simply pumping as much as it can. This is NOT the case for an OMP. For example, let off the gas completely at 9,000rpm. The stepper motor drops significantly (almost nothing), but you still have near max engine oil pressure. You can go full throttle at 3,500rpm and get near max OMP flow, but have less than max engine oil pressure. There is an oil pressure regulator that keeps engine oil pressure at a specific rate for much of the RPM rev range, where the OMP will supply oil flow based on LOAD, not on RPM.
What relationship are you referring to again?
As long as oil is available to the stepper motor, the stepper motor determines how much oil is supplied, and the pressure of that oil supply has nothing to do with it.
Yes, there is a relationship between flow and pressure in a normal system that is simply pumping as much as it can. This is NOT the case for an OMP. For example, let off the gas completely at 9,000rpm. The stepper motor drops significantly (almost nothing), but you still have near max engine oil pressure. You can go full throttle at 3,500rpm and get near max OMP flow, but have less than max engine oil pressure. There is an oil pressure regulator that keeps engine oil pressure at a specific rate for much of the RPM rev range, where the OMP will supply oil flow based on LOAD, not on RPM.
What relationship are you referring to again?
As long as oil is available to the stepper motor, the stepper motor determines how much oil is supplied, and the pressure of that oil supply has nothing to do with it.
#377
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I don't think you understand how the stepper motor works. It's never "open". It has full control of exactly how much it is flowing, regardless of pressure.
Don't think garden hose. Think a line of kids with buckets as you request them. You can determine how fast they hand you the next bucket in line. It doesn't matter how fast they fill the buckets, you still have complete control over how many buckets you accept from them.
Don't think garden hose. Think a line of kids with buckets as you request them. You can determine how fast they hand you the next bucket in line. It doesn't matter how fast they fill the buckets, you still have complete control over how many buckets you accept from them.
#378
I don't think you understand how the stepper motor works. It's never "open". It has full control of exactly how much it is flowing, regardless of pressure.
Don't think garden hose. Think a line of kids with buckets as you request them. You can determine how fast they hand you the next bucket in line. It doesn't matter how fast they fill the buckets, you still have complete control over how many buckets you accept from them.
Don't think garden hose. Think a line of kids with buckets as you request them. You can determine how fast they hand you the next bucket in line. It doesn't matter how fast they fill the buckets, you still have complete control over how many buckets you accept from them.
#379
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Yes, correct. Stepper motors were designed to precisely control how much the driven shaft moves, and in the case of the OMP, that driven shaft only rotates in steps to supply a fixed amount of oil on each step to regulate how much oil is being supplied.
The pressure of the supply won't change the amount regulated.
The pressure of the supply won't change the amount regulated.
#380
Yes, correct. Stepper motors were designed to precisely control how much the driven shaft moves, and in the case of the OMP, that driven shaft only rotates in steps to supply a fixed amount of oil on each step to regulate how much oil is being supplied.
The pressure of the supply won't change the amount regulated.
The pressure of the supply won't change the amount regulated.
#382
Warmed up car after a drive(~35miles) turned off car in a garage(my drive way isnt level) and pulled dip stick(i have 3 extras) so i scored the level, cleaned it off. Went for a drive in the route(no lights one stop sign, plus i went aroung 12pm for no traffic issues or increased run time) and parked in same spot in garage marked with tire chalks in the same direction. Let car cool for aprox 7-10 minutes. Checked the dipstick. Had a box full of 50ml medical plunger things(cant think of the name right now) and added until the oil meniscus was at score mark. And did that 4 times. Well 3 times with that exact way. First time i just found route and video taped driving habit. And yes my MOP rates were aprox 65% over stock from beginning with and without SOHN. Im probably missing stuff but id appreciate any insight!
#383
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Your measuring method may be skewing your results.
The temperature of the engine can change the level indicated on the dipstick by as much as half a liter. The first correction to your test method will need to be checking it and measuring it at as close as possible to the same temperature each time, and probably should record that temp each time.
The 2nd improvement is to use something other than the dipstick, due to factors that can influence the result, such as oil dragged up the side of the dipstick tube. Plus it's not all that precise.
I'm not saying your numbers are wrong, but at the moment they are still untrustworthy.
A better method might be to measure actual output via the OMP lines. I'm sure you could figure out a way to run the OMP output into a controlled device to measure how much moves through. If you do this only at idle, it should solve several of your variable factors, such as load (it's known and repeatable). Measure the amount of oil moved through over a specific time duration a few times via each supply method.
I would recommend a heavy premix while you do this.
If there IS a SOHN injection drop, it would be good to know, and it would be good to know how much so injection tables can be adjusted up accordingly. But that test method isn't going to get much traction around here.
The temperature of the engine can change the level indicated on the dipstick by as much as half a liter. The first correction to your test method will need to be checking it and measuring it at as close as possible to the same temperature each time, and probably should record that temp each time.
The 2nd improvement is to use something other than the dipstick, due to factors that can influence the result, such as oil dragged up the side of the dipstick tube. Plus it's not all that precise.
I'm not saying your numbers are wrong, but at the moment they are still untrustworthy.
A better method might be to measure actual output via the OMP lines. I'm sure you could figure out a way to run the OMP output into a controlled device to measure how much moves through. If you do this only at idle, it should solve several of your variable factors, such as load (it's known and repeatable). Measure the amount of oil moved through over a specific time duration a few times via each supply method.
I would recommend a heavy premix while you do this.
If there IS a SOHN injection drop, it would be good to know, and it would be good to know how much so injection tables can be adjusted up accordingly. But that test method isn't going to get much traction around here.
#385
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Warmed up car after a drive(~35miles) turned off car in a garage(my drive way isnt level) and pulled dip stick(i have 3 extras) so i scored the level, cleaned it off. Went for a drive in the route(no lights one stop sign, plus i went aroung 12pm for no traffic issues or increased run time) and parked in same spot in garage marked with tire chalks in the same direction. Let car cool for aprox 7-10 minutes. Checked the dipstick. Had a box full of 50ml medical plunger things(cant think of the name right now) and added until the oil meniscus was at score mark. And did that 4 times. Well 3 times with that exact way. First time i just found route and video taped driving habit. And yes my MOP rates were aprox 65% over stock from beginning with and without SOHN. Im probably missing stuff but id appreciate any insight!
If you drove the exact same way and did not romp on it during any of those identical trips, then that might be a somewhat accurate way to measure it. But the consumption rate depends mainly on engine load, not run time or mileage.
#386
Your measuring method may be skewing your results.
The temperature of the engine can change the level indicated on the dipstick by as much as half a liter. The first correction to your test method will need to be checking it and measuring it at as close as possible to the same temperature each time, and probably should record that temp each time.
The 2nd improvement is to use something other than the dipstick, due to factors that can influence the result, such as oil dragged up the side of the dipstick tube. Plus it's not all that precise.
I'm not saying your numbers are wrong, but at the moment they are still untrustworthy.
A better method might be to measure actual output via the OMP lines. I'm sure you could figure out a way to run the OMP output into a controlled device to measure how much moves through. If you do this only at idle, it should solve several of your variable factors, such as load (it's known and repeatable). Measure the amount of oil moved through over a specific time duration a few times via each supply method.
I would recommend a heavy premix while you do this.
If there IS a SOHN injection drop, it would be good to know, and it would be good to know how much so injection tables can be adjusted up accordingly. But that test method isn't going to get much traction around here.
The temperature of the engine can change the level indicated on the dipstick by as much as half a liter. The first correction to your test method will need to be checking it and measuring it at as close as possible to the same temperature each time, and probably should record that temp each time.
The 2nd improvement is to use something other than the dipstick, due to factors that can influence the result, such as oil dragged up the side of the dipstick tube. Plus it's not all that precise.
I'm not saying your numbers are wrong, but at the moment they are still untrustworthy.
A better method might be to measure actual output via the OMP lines. I'm sure you could figure out a way to run the OMP output into a controlled device to measure how much moves through. If you do this only at idle, it should solve several of your variable factors, such as load (it's known and repeatable). Measure the amount of oil moved through over a specific time duration a few times via each supply method.
I would recommend a heavy premix while you do this.
If there IS a SOHN injection drop, it would be good to know, and it would be good to know how much so injection tables can be adjusted up accordingly. But that test method isn't going to get much traction around here.
And yes right now i premix aprox 20oz per tank. Using motul 800v off road.
#388
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I'm not saying that your conclusions are wrong, just that the support for the conclusions is too shaky for any of us to take it at face value. You could have had a wind speed change, a greater load variance than you realize, plus anything else previously mentioned. There is even the possibility that a portion of the oil being consumed ISN'T going through the OMP.
Not being hostile here, just stating that if you want us to agree with you, you are going to have to eliminate as many of those factors as possible. Testing actual output of the OMP in a controlled environment is going to be needed to prove your case. You can physically connect to output via the OMP lines, and you can test it all with the engine at idle which will eliminate load changes as a factor. It would be a much better test, and one that I don't think anyone would argue with.
We could then get on to arguing why it's different So far, we only have suggestions that it is, with no evidence.
And my heavy premix recommendation was for when you have the OMP lines disconnected for the idle test. You are probably over-doing it for normal driving with the OMP connected.
Not being hostile here, just stating that if you want us to agree with you, you are going to have to eliminate as many of those factors as possible. Testing actual output of the OMP in a controlled environment is going to be needed to prove your case. You can physically connect to output via the OMP lines, and you can test it all with the engine at idle which will eliminate load changes as a factor. It would be a much better test, and one that I don't think anyone would argue with.
We could then get on to arguing why it's different So far, we only have suggestions that it is, with no evidence.
And my heavy premix recommendation was for when you have the OMP lines disconnected for the idle test. You are probably over-doing it for normal driving with the OMP connected.
#389
I'm not saying that your conclusions are wrong, just that the support for the conclusions is too shaky for any of us to take it at face value. You could have had a wind speed change, a greater load variance than you realize, plus anything else previously mentioned. There is even the possibility that a portion of the oil being consumed ISN'T going through the OMP.
Not being hostile here, just stating that if you want us to agree with you, you are going to have to eliminate as many of those factors as possible. Testing actual output of the OMP in a controlled environment is going to be needed to prove your case. You can physically connect to output via the OMP lines, and you can test it all with the engine at idle which will eliminate load changes as a factor. It would be a much better test, and one that I don't think anyone would argue with.
We could then get on to arguing why it's different So far, we only have suggestions that it is, with no evidence.
And my heavy premix recommendation was for when you have the OMP lines disconnected for the idle test. You are probably over-doing it for normal driving with the OMP connected.
Not being hostile here, just stating that if you want us to agree with you, you are going to have to eliminate as many of those factors as possible. Testing actual output of the OMP in a controlled environment is going to be needed to prove your case. You can physically connect to output via the OMP lines, and you can test it all with the engine at idle which will eliminate load changes as a factor. It would be a much better test, and one that I don't think anyone would argue with.
We could then get on to arguing why it's different So far, we only have suggestions that it is, with no evidence.
And my heavy premix recommendation was for when you have the OMP lines disconnected for the idle test. You are probably over-doing it for normal driving with the OMP connected.
I don't want anyone to take and live by it. I want people to logically think and experiment, and hopefully someone come with solid evidence. I've seen people with brand new engines, throw a SOHN on there, some people are 90k miles with good compression (premix heavily) other I've seen fail with the SOHN, premix moderately about 10oz per tank and loss of compression within 20k. of course theres too many variables BUT other people on Facebook have also had this experience, and one guy brought up similar finding of oil consumption, with and without SOHN. he found more wear on all parts internally with SOHN than stock MOP. Any ways, i learned some new info, might be cranking up my MOP once again lol but now, I'm saving up for a pcettitracing OTS engine hopefully!
#390
checked it about after maybe 3 tanks, nothing yet but since my engine is on its way out i don't drive it anymore, i wanna save up for a new engine and hopefully tear this one down in my own time and hopefully rebuild or sell good parts! And I'm ok with new plugs yearly, can't expect a miracle lol
#391
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I've seen people with brand new engines, throw a SOHN on there, some people are 90k miles with good compression (premix heavily) other I've seen fail with the SOHN, premix moderately about 10oz per tank and loss of compression within 20k. of course theres too many variables
Frankly, the SOHN/OMP can affect only a couple possible failure methods. If you aren't looking at ONLY those failure methods, the findings of casual online surveys are going to be worthless.
Without trying to brag about it, 4.5 years ago I conducted the most thorough survey of engine failures on the forum, including maintenance information, driving style information, modifications, and a bunch of other factors.
Here is the original thread: https://www.rx8club.com/rx-8-discuss...survey-202333/
I got a total of 108 responses, 2 of those were in January of this year, the 3rd most recent was 11/8/2012. It's more feedback than any other poll or survey done by anyone about this (pretty sure we would have heard of something bigger than this, it would have to show up in the largest RX-8 online community in the world for participants), and it is more thorough with the questions and data points than any other survey as well.
And it is still completely inconclusive. I'd need to cross at least 1,000 responses before I'd have ANYTHING meaningful, and even then it would probably only be on a few points. More than 5,000 would probably be required before I could cover most points with a conclusion.
As time goes on, most owners are not original owners, and would not be able to provide a single piece of information about most of the car's lifespan, so these surveys and polls get even more meaningless.
So be wary of casual surveys with basically no information behind them.
Again...
We totally understand this. You just need to take it even farther than you have so far.
#392
You aren't asking for anything different than what we are. We are just pointing out the points where your evidence can't really hold up yet. You are on the right track to get to the bottom of the matter, you just have to remove more unknown variables.
Yes, there are many many variables. One example: A large % of engines are lost due to cooling seal failure... it would be inaccurate to assume that the SOHN / OMP / Premix has anything to do with that. Most of those are simple cooling system neglect.
Frankly, the SOHN/OMP can affect only a couple possible failure methods. If you aren't looking at ONLY those failure methods, the findings of casual online surveys are going to be worthless.
Without trying to brag about it, 4.5 years ago I conducted the most thorough survey of engine failures on the forum, including maintenance information, driving style information, modifications, and a bunch of other factors.
Here is the original thread: https://www.rx8club.com/rx-8-discuss...survey-202333/
I got a total of 108 responses, 2 of those were in January of this year, the 3rd most recent was 11/8/2012. It's more feedback than any other poll or survey done by anyone about this (pretty sure we would have heard of something bigger than this, it would have to show up in the largest RX-8 online community in the world for participants), and it is more thorough with the questions and data points than any other survey as well.
And it is still completely inconclusive. I'd need to cross at least 1,000 responses before I'd have ANYTHING meaningful, and even then it would probably only be on a few points. More than 5,000 would probably be required before I could cover most points with a conclusion.
As time goes on, most owners are not original owners, and would not be able to provide a single piece of information about most of the car's lifespan, so these surveys and polls get even more meaningless.
So be wary of casual surveys with basically no information behind them.
Again...
We totally understand this. You just need to take it even farther than you have so far.
Yes, there are many many variables. One example: A large % of engines are lost due to cooling seal failure... it would be inaccurate to assume that the SOHN / OMP / Premix has anything to do with that. Most of those are simple cooling system neglect.
Frankly, the SOHN/OMP can affect only a couple possible failure methods. If you aren't looking at ONLY those failure methods, the findings of casual online surveys are going to be worthless.
Without trying to brag about it, 4.5 years ago I conducted the most thorough survey of engine failures on the forum, including maintenance information, driving style information, modifications, and a bunch of other factors.
Here is the original thread: https://www.rx8club.com/rx-8-discuss...survey-202333/
I got a total of 108 responses, 2 of those were in January of this year, the 3rd most recent was 11/8/2012. It's more feedback than any other poll or survey done by anyone about this (pretty sure we would have heard of something bigger than this, it would have to show up in the largest RX-8 online community in the world for participants), and it is more thorough with the questions and data points than any other survey as well.
And it is still completely inconclusive. I'd need to cross at least 1,000 responses before I'd have ANYTHING meaningful, and even then it would probably only be on a few points. More than 5,000 would probably be required before I could cover most points with a conclusion.
As time goes on, most owners are not original owners, and would not be able to provide a single piece of information about most of the car's lifespan, so these surveys and polls get even more meaningless.
So be wary of casual surveys with basically no information behind them.
Again...
We totally understand this. You just need to take it even farther than you have so far.
#393
weeeeeeeeee
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Take it up with Richard directly (Richard Sohn is the owner of Rotary Aviation): Featured Products - Rotary Aviation.com
Mod Edit: Image removed
Mod Edit: Image removed
#396
There is no pump in the system, there never was, its just a mechanical stepper... No? And if theres no pressure how does the front cover get oil source? If you day the engine itself, since its not a seperate system, it would still have pressure, granted not as high the whole system, still a pressure. And yes RIWWP does have patience and i feel more knowledge for taking the time to explain things, than sound like hes the engineer mazda paid and thats how it is....
#397
Modulated Moderator
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There is no pump in the system, there never was, its just a mechanical stepper... No? And if theres no pressure how does the front cover get oil source? If you day the engine itself, since its not a seperate system, it would still have pressure, granted not as high the whole system, still a pressure. And yes RIWWP does have patience and i feel more knowledge for taking the time to explain things, than sound like hes the engineer mazda paid and thats how it is....
Have you ever seen the front cover removed?...Or taken an OMP apart? Until you do don't be so damn sure you know what's going on.....
If you would like I will repost the pictures of the inside of the OMP and maybe you will understand how it works
Just to check your logic.....is there pressure in the sump of the oil pan?...why not? It is part of the oil system
#398
weeeeeeeeee
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To quote Interstellar:
GRAVITY
with a little help from its friend VACUUM.
Seriously... WTH are we debating here? I literally just filled my reservoir for the 2nd time in 1000 miles with a quart of golden idemitsu premix.
GRAVITY
with a little help from its friend VACUUM.
Seriously... WTH are we debating here? I literally just filled my reservoir for the 2nd time in 1000 miles with a quart of golden idemitsu premix.
Last edited by ShellDude; 04-09-2015 at 06:46 PM.
#399
Ive seen pictures from MM and ive talked with him, maybe you can explain better?