OMP mod/improvement Idea
03-20-17, 11:57 PM
#26
i thought we already discussed it?
btw, i love me some premix.
ok ok, no, i don't know of a way to modify the FD OMP. you'd be better off seeing if you can hack the FC 4 port OMP to work, but as mentioned i don't recall if the bolt patterns match up. i never had any inclination to check on that one.
others have suggested fixes for your particular situation but, they are premix based. a bottle fed into the tank that you could control how much you put in without getting your hands dirty. maybe not as ideal as an injection system but it is certainly less work than trying to make a 4 injector system.
your other alternative is to merely move the 2 that you have to the intake and block the rotor housing ports. if you have a PFC you can inject as much oil as you wish with the datalogit. the FC secondary injectors are long enough to be ideal for placing in the intake, since that is where they live however you might have to ream out the orifice with a jewelers bit to get more oil flow through them.
btw, i love me some premix.
ok ok, no, i don't know of a way to modify the FD OMP. you'd be better off seeing if you can hack the FC 4 port OMP to work, but as mentioned i don't recall if the bolt patterns match up. i never had any inclination to check on that one.
others have suggested fixes for your particular situation but, they are premix based. a bottle fed into the tank that you could control how much you put in without getting your hands dirty. maybe not as ideal as an injection system but it is certainly less work than trying to make a 4 injector system.
your other alternative is to merely move the 2 that you have to the intake and block the rotor housing ports. if you have a PFC you can inject as much oil as you wish with the datalogit. the FC secondary injectors are long enough to be ideal for placing in the intake, since that is where they live however you might have to ream out the orifice with a jewelers bit to get more oil flow through them.
Last edited by RotaryEvolution; 03-21-17 at 12:04 AM.
03-21-17, 01:31 AM
#27
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Thank you.
I've considered some kind of 'feed into tank' system but didn't get very far. Has anyone one implemented one that you know of? I'd be interested to see how they did it because I'm a bit stumped.
As for the additional injector idea, I still have many questions and concerns to discuss for those willing:
The 20B OMP has an externally identical housing to the 13B Denso one with one additional port opened up, which I take as 'proof of concept' for potential 4 port modification.
The next step would be to compare the insides, where I imagine the oil passage on the pump will be a bit bigger on the 20B. The difference will tell us how much the 13B one needs to be enlarged to supply 4 pumps with a proportional flow.
Sgtblue raised a valid concern here though, what will happen to idle with the extra oil? This could potentially be controlled by the size of the injectors. As you mentioned, the FC ones are going to be ideal for the intake due to their length, but I have no idea how their nozzle size compares to the FD ones (neither the early large ones of small late one), or what combination of all of them will yield the best results. PFC control may solve the problem as well.
Another potential fix would be to modify the FD Mikuni OMP instead, which has 2 pumps inside. You could enlarge only the oil passage on the large pump so there is only extra flow at higher RPM or under load. The Mikuni only has 2 ports however, and no room for modification. Double banjo bolts would need to be used, unless... the RX8 OMP could be used.
The (early) RX8 OMP is also Mikuni and appears to essentially be a 4 port version of the FD one. The RX8 uses an external position sensor (just a repurposed TPS) while the FD position sensor is internal, but besides that they appear extremely similar. Flow rates would need to be compared somehow to accurately adjust flow if necessary. I know RB offered RX8 OMP's modified for more flow which I also a bit of 'proof of concept'.
EDIT: The reason I am asking all this is because this mod would be very hard to test in the real world. Too many other variables in play to accurately get results. Especially when you're not starting with a fresh engine. This is why I want the idea to be completely sound in concept before being implemented.
I've considered some kind of 'feed into tank' system but didn't get very far. Has anyone one implemented one that you know of? I'd be interested to see how they did it because I'm a bit stumped.
As for the additional injector idea, I still have many questions and concerns to discuss for those willing:
The 20B OMP has an externally identical housing to the 13B Denso one with one additional port opened up, which I take as 'proof of concept' for potential 4 port modification.
The next step would be to compare the insides, where I imagine the oil passage on the pump will be a bit bigger on the 20B. The difference will tell us how much the 13B one needs to be enlarged to supply 4 pumps with a proportional flow.
Sgtblue raised a valid concern here though, what will happen to idle with the extra oil? This could potentially be controlled by the size of the injectors. As you mentioned, the FC ones are going to be ideal for the intake due to their length, but I have no idea how their nozzle size compares to the FD ones (neither the early large ones of small late one), or what combination of all of them will yield the best results. PFC control may solve the problem as well.
Another potential fix would be to modify the FD Mikuni OMP instead, which has 2 pumps inside. You could enlarge only the oil passage on the large pump so there is only extra flow at higher RPM or under load. The Mikuni only has 2 ports however, and no room for modification. Double banjo bolts would need to be used, unless... the RX8 OMP could be used.
The (early) RX8 OMP is also Mikuni and appears to essentially be a 4 port version of the FD one. The RX8 uses an external position sensor (just a repurposed TPS) while the FD position sensor is internal, but besides that they appear extremely similar. Flow rates would need to be compared somehow to accurately adjust flow if necessary. I know RB offered RX8 OMP's modified for more flow which I also a bit of 'proof of concept'.
EDIT: The reason I am asking all this is because this mod would be very hard to test in the real world. Too many other variables in play to accurately get results. Especially when you're not starting with a fresh engine. This is why I want the idea to be completely sound in concept before being implemented.
Last edited by Oggy; 03-21-17 at 01:38 AM.
03-21-17, 05:54 AM
#28
Obviously you enjoy doing these sorts of things but for most of us I still think it's far more work than its worth...even with NJ's lack of confidence in its people. Likely still fixing an unbroken system. And if you've never had the pleasure, know that R & R'ing the OMP, at least with the twins, isn't a walk in the park.
03-22-17, 01:34 PM
#31
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(1) Get the Rotary Aviation OMP adapter
Oil Metering Pump Adapters.
(2) Install a separate tank to feed it with 2cycle racing oil or Idemitsu premix oil.
(3) Get a non Mazda ECU that allows increasing the OMP flow. The PFC does this.
Oil Metering Pump Adapters.
(2) Install a separate tank to feed it with 2cycle racing oil or Idemitsu premix oil.
(3) Get a non Mazda ECU that allows increasing the OMP flow. The PFC does this.
03-22-17, 01:43 PM
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Obviously you enjoy doing these sorts of things but for most of us I still think it's far more work than its worth...even with NJ's lack of confidence in its people. Likely still fixing an unbroken system. And if you've never had the pleasure, know that R & R'ing the OMP, at least with the twins, isn't a walk in the park.
It's becoming more and more clear that this is something I will need to R&D on my own at a later date when I have all of these parts in front of me on the work bench... which it totally fine. As you figured, I do quite enjoy this kind of thing.
03-22-17, 04:06 PM
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Just to be clear, you cannot raise the maximum flow rate of the OMP with a standalone ECU. A stepper motor on the OMP controls how much oil is allowed to flow through the oil passage on the pump. You can adjust the stepper motor to allow more flow at low rpm/load but you cannot increase the flow at 100% duty.
03-23-17, 12:21 PM
#37
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The OMP controls oil flow by rpm and engine load and is run by the ECU.
The PFC "Oiler Vs. Water Temp" table allows adjustment of more or less oil flow for three
temperatures and the ranges around them. This can be seen as the OMP voltage will change.
03-23-17, 01:17 PM
#38
So I started writing a response and I realized it's going to need its own thread, if I can get it organized enough. I'll give a response that's to the point and hopefully not too long. The apex seal gets much hotter at the center than at the edges. That's why they put the injectors in the middle and can still easily provide enough lubrication.
It's easy to over lubricate the apex seal. Mazda for example tuned the stock OMP maps by running the engine continuously at WOT. The engine never runs continuously in real life because rpm and load are constantly changing, even in racing. So there's already a big margin in the flow rate of capability of the OMP and in the calibration.
It takes time for the apex seal to reach such high temperatures. Here is an engine dyno run where they started at coasting, 1000rpm and ramped to 5000 WOT in 15 seconds (basically a 4th gear pull) and then had it sit there at 45 seconds WOT. It took that 45 seconds for the apex seal to reach peak temperature. That kind of abuse hardly ever happens in real life, unless you are doing a full mile run.
For the FD, they took out the intake manifold oil injectors because the FD rotor housings have much lower friction, so why bother with the additional complexity when the 2 injectors are more than enough.
As an aside, notice how the standard chrome plating, which is probably what you are going to get with a "re chromed" housing, is so much higher friction - ie it needs more lubrication oil, so you should definitely premix if you have re chromed housings.
So the stock OMP was designed to deliver enough oil for very, very severe conditions found in a lab environment that your engine never runs during back roads driving or street commuting, and only MAYBE under actual race track use. Turning up the boost doesn't help temps but you also add tons of fuel in the combustion chamber which probably does help. Here's a graph depicting the stock OMP map for a series 5 2nd gen (not sure if turbo or not). It shows that most of the oil is delivered at high speed and load, probably so they could do lab durability tests (many many hours of continuous WOT running).
Based on all that I'm going to say adding premix or even additional oil injectors is probably a waste of time for the vast majority of applications that don't involve severe (and I mean severe) track use. Dropping the hammer at a stop light or banging through 3rd gear to accelerate on to the highway isn't even close to the severe conditions Mazda used to size the OMP flow rates and tune the stock maps. That's because it takes time for the seal to get hot. Now I have no idea how the Power FC's mapping compares to the stock ECU, but I'm guessing it's similar.
It's easy to over lubricate the apex seal. Mazda for example tuned the stock OMP maps by running the engine continuously at WOT. The engine never runs continuously in real life because rpm and load are constantly changing, even in racing. So there's already a big margin in the flow rate of capability of the OMP and in the calibration.
It takes time for the apex seal to reach such high temperatures. Here is an engine dyno run where they started at coasting, 1000rpm and ramped to 5000 WOT in 15 seconds (basically a 4th gear pull) and then had it sit there at 45 seconds WOT. It took that 45 seconds for the apex seal to reach peak temperature. That kind of abuse hardly ever happens in real life, unless you are doing a full mile run.
For the FD, they took out the intake manifold oil injectors because the FD rotor housings have much lower friction, so why bother with the additional complexity when the 2 injectors are more than enough.
As an aside, notice how the standard chrome plating, which is probably what you are going to get with a "re chromed" housing, is so much higher friction - ie it needs more lubrication oil, so you should definitely premix if you have re chromed housings.
So the stock OMP was designed to deliver enough oil for very, very severe conditions found in a lab environment that your engine never runs during back roads driving or street commuting, and only MAYBE under actual race track use. Turning up the boost doesn't help temps but you also add tons of fuel in the combustion chamber which probably does help. Here's a graph depicting the stock OMP map for a series 5 2nd gen (not sure if turbo or not). It shows that most of the oil is delivered at high speed and load, probably so they could do lab durability tests (many many hours of continuous WOT running).
Based on all that I'm going to say adding premix or even additional oil injectors is probably a waste of time for the vast majority of applications that don't involve severe (and I mean severe) track use. Dropping the hammer at a stop light or banging through 3rd gear to accelerate on to the highway isn't even close to the severe conditions Mazda used to size the OMP flow rates and tune the stock maps. That's because it takes time for the seal to get hot. Now I have no idea how the Power FC's mapping compares to the stock ECU, but I'm guessing it's similar.