OMP Oil Metering pump output and modification - Page 3 - RX8Club.com

Go Back  RX8Club.com > Series I Tech & Performance > Series I Tech Garage
Reload this Page >

OMP Oil Metering pump output and modification

Notices
Series I Tech Garage The place to discuss anything technical about the RX-8 that doesn't fit into any of the categories below.

OMP Oil Metering pump output and modification

Reply

 
 
 
Old 10-18-2018, 06:10 PM
  #51  
Boosted Kiwi
Thread Starter
iTrader: (2)
 
Brettus's Avatar
 
Join Date: Apr 2006
Location: Y-cat-o NZ
Posts: 18,182
Thanked 201 Times in 154 Posts
Originally Posted by kevink0000 View Post
That sounds like internal leakage to my untrained mind. ...
Agreed ... has to be !
A test with it on the engine may tell us more but that would be a mission .
Brettus is online now  
Reply With Quote
Old 10-18-2018, 06:28 PM
  #52  
Registered
 
kevink0000's Avatar
 
Join Date: Sep 2017
Location: Arizona
Posts: 74
Thanked 6 Times in 4 Posts
Yes, a big job, especially running with oil injectors in place to see what goes on. I wonder if the better builders use injection at all when breaking engines in. They may have some tales to tell as well...
kevink0000 is offline  
Reply With Quote
Old 10-30-2018, 01:59 PM
  #53  
Registered
 
kevink0000's Avatar
 
Join Date: Sep 2017
Location: Arizona
Posts: 74
Thanked 6 Times in 4 Posts
Just ran the pump with a drilled large pump in the small location, and got enough miles to determine new consumption, and it IS greater. I get about 900-950 miles per quart now with a fully completed mod#2 under moderate driving, with a mixture of city and highway. I am personally happy with that consumption level, as my old 12a FB was in a similar range under normal driving conditions also. (800-1000 miles per quart, but with crankcase oil injected) Again this is consumption rate with a Sohn and 2 stroke oil injected.
kevink0000 is offline  
Reply With Quote
Old 10-30-2018, 07:31 PM
  #54  
Boosted Kiwi
Thread Starter
iTrader: (2)
 
Brettus's Avatar
 
Join Date: Apr 2006
Location: Y-cat-o NZ
Posts: 18,182
Thanked 201 Times in 154 Posts
Did you mean greater than without the hole ...or greater than with the smaller pump ?
Of course ...you know what the test you need to do now is ............... no Sohn
Brettus is online now  
Reply With Quote
Old 10-30-2018, 08:47 PM
  #55  
Registered
 
kevink0000's Avatar
 
Join Date: Sep 2017
Location: Arizona
Posts: 74
Thanked 6 Times in 4 Posts
Yes, greater than with stock unmodified pump, (by a factor of 2+) and greater than with my initial undrilled large pump in small side Mod#2. I was getting about 1200 miles/quart before drilling and about 925 miles/quart now. So Bret, thanks much for the insight on the pump!
No crankcase oil for me anymore! I like 2 stroke. I worked on many 2 strokes in a shop years and years ago, and you could ALWAYS tell when the customer ran regular motor oil instead of 2 stroke oil. It just goes against my grain. I had my old 12a pump apart and was going to modify it to take 2 stroke oil, (in the pre-sohn days of the mid 80s) but never got around to it. I just never liked the idea of crankcase oil burning in the chamber. Especially at very lean mixture rates.
kevink0000 is offline  
Reply With Quote
Old 10-31-2018, 03:41 AM
  #56  
Boosted Kiwi
Thread Starter
iTrader: (2)
 
Brettus's Avatar
 
Join Date: Apr 2006
Location: Y-cat-o NZ
Posts: 18,182
Thanked 201 Times in 154 Posts
Originally Posted by kevink0000 View Post
Yes, greater than with stock unmodified pump, (by a factor of 2+) and greater than with my initial undrilled large pump in small side Mod#2. I was getting about 1200 miles/quart before drilling and about 925 miles/quart now. So Bret, thanks much for the insight on the pump!
.
Sounds perfect ....... would love to do a long term trial and see if we can get better longevity with this setup !
Brettus is online now  
Reply With Quote
Old 11-01-2018, 11:49 PM
  #57  
Registered
 
Join Date: May 2005
Location: Eastern Ontario
Posts: 295
Thanked 0 Times in 0 Posts
Originally Posted by Brettus View Post
I'm really leaning toward your way of thinking .
With a stock OMP :
*Street cars that spend very little time in higher rpm/load range wear out the housings very quickly .... I've seen heaps of housings in engines from 50000 miles up to 100,000 miles . The housings are always worn out.
* Race car engines last quite a long time and wear on the housings is minimal after many races .

Conclusion : not enough oil at low load rpm on the smaller pump but sufficient oil for high load/rpm once large pump kicks in.
IMO this is the most significant statement made in connection with improving engine longevity. Whereas this started out as an exploratory investigation of an interesting and ingenious device, it evolved to the stage of being a must-do-something to get more oil into the combustion chambers. I would never have guessed that race engines experience less wear than street cars.

This thread needs more input. The lack of more community involvement I believe is due to the lack of understanding of what exactly is going on. To remedy this, it would be appropriate for one or both of your guys to write a technical type document outlining what you know about how this pump works, especially the valving. Your mods also need more explanation particularly with respect to 'drilling', as do your experimental results. I believe then that more people will jump in with fresh ideas on ways to improve oil flow to the injectors. Anyway, thanks to both of you for your commitment to this project.
Delmeister is offline  
Reply With Quote
Old 11-01-2018, 11:55 PM
  #58  
Zoom-Freakin'-Zoom
iTrader: (5)
 
swoope's Avatar
 
Join Date: Jan 2004
Location: orlando, fl
Posts: 14,564
Thanked 15 Times in 13 Posts
i have a spare pump out of the car if you guys need to test or need to play with.

and two motors that have need of improvement. and an rx8 track car that cant track..

and i ship to NZ! lol

beers
swoope is offline  
Reply With Quote
Old 11-02-2018, 12:04 AM
  #59  
Registered
 
kevink0000's Avatar
 
Join Date: Sep 2017
Location: Arizona
Posts: 74
Thanked 6 Times in 4 Posts
Delmeister,
Yes! Brettus has done a great job researching this pump and posting the details. I was looking for info like this myself, before I bought my first RX8. Your originial OMP posts were read and re-read by me several times. Unfortunately there is still some mystery to it, even after all these years!
In my opinion, the place to look for most longevity improvements in the Renesis involve emissions. Many compromises were made to meet emissions targets, and then maintain the life of the cat over the state mandated periods. If we look at reversing some of those engineering decisions, lifespan will increase exponentially. Again, I believe this was the first OBDII rotary and as such had many extreme measures taken to meet emissions laws, with lifespan the main loser, and peak power and economy second.
kevink0000 is offline  
Reply With Quote
Old 11-03-2018, 06:02 PM
  #60  
Boosted Kiwi
Thread Starter
iTrader: (2)
 
Brettus's Avatar
 
Join Date: Apr 2006
Location: Y-cat-o NZ
Posts: 18,182
Thanked 201 Times in 154 Posts
Thanks guys . Ironically , I'm not even running the omp anymore as it was getting in the way of my turbo intake. However , I do think the mod #2 with a little tweaking of the ECU map could be the way to go for both street and small turbo setups without any need for premix.
Brettus is online now  
Reply With Quote
Old 11-03-2018, 07:18 PM
  #61  
Registered
 
Join Date: Sep 2018
Location: Down Under
Posts: 162
Thanked 4 Times in 4 Posts
Brettus I know in USA Mazda do an ECU Flash to increase OMP flow but I have asked Mazda here in Oz but they have no such thing they reckon
Sydo is online now  
Reply With Quote
Old 12-03-2018, 08:32 PM
  #62  
Boosted Kiwi
Thread Starter
iTrader: (2)
 
Brettus's Avatar
 
Join Date: Apr 2006
Location: Y-cat-o NZ
Posts: 18,182
Thanked 201 Times in 154 Posts
Update : A recent discussion on the Purely site has filled in the gaps for me about a few things .
Firstly , here is a quote from Don Walker , a guy who has raced rx8s extensively . We were discussing how much oil pressure there was supplying the OMP ...

I did. We saw idle oil pressure (18-20psi hot at idle and about 40psi at higher rpm. Because of the way the oil feed port is designed it does restrict oil pressure, but if you start the engine with the OMP off it will shoot a laser beam of oil across your shop
He says he made up a blanking plate specifically to measure this pressure .

Secondly re the Sohn Adapter :

What Brett noticed and what you are theorizing is correct. At low to moderate engine speed and load the gravity feed is just barely enough, but as engine RPM and load increase the gravity feed cannot keep up and not enough oil is injected. What has saved the Sohn guys so far is they are almost entirely street cars and still premix as you yourself stated in the oil thread. It is literally the mantra "Sohn adapter and premix". Well, ok but if you are going to do that save yourself the money and potential failure of the Sohn and just premix
​​​​​​​Gary that is why I only ever talk about the results on the track of the Sohn vs standard cars. The Sohn car ate engines (on my competitors car he destroyed an engine every weekend, and at Mid-Ohio he killed an engine every single session he was on track) while the standard car never had an issue. Also the amount of oil used was extremely telling. The sohn used half as much oil at best as did the standard car. You cannot and will not ever convince me the Sohn provides anything but a failure point when it is using 1/8th to a 1/4qt of oil vs a 1/2 or more qt of oil in the same session on the same track in nearly identical cars. And that is the real key. Now yes, we were running the cars hard, shifting at 9400 and the engines rarely dropped below 3k on track, but at a track like St Pete, which is a street course you are going all the way down to 2nd and back up to 5th several times per lap, 10 or 12 laps in a session, so believe this is as close as mere mortals can get to a proper stress test.
Brettus is online now  
Reply With Quote
The Following User Says Thank You to Brettus For This Useful Post:
kevink0000 (12-06-2018)
Old 12-04-2018, 03:45 PM
  #63  
Registered
iTrader: (1)
 
FazdaRX_8's Avatar
 
Join Date: Jun 2009
Posts: 2,018
Thanks: 0
Thanked 4 Times in 4 Posts
so based on this information, those of us with access to the OMP map can't we just increase it further for low loads and cruising?

I personally have always had the idle and cruise regions higher. now I wonder if I should go more
FazdaRX_8 is offline  
Reply With Quote
Old 12-04-2018, 03:46 PM
  #64  
Boosted Kiwi
Thread Starter
iTrader: (2)
 
Brettus's Avatar
 
Join Date: Apr 2006
Location: Y-cat-o NZ
Posts: 18,182
Thanked 201 Times in 154 Posts
Originally Posted by FazdaRX_8 View Post
so based on this information, those of us with access to the OMP map can't we just increase it further for low loads and cruising?

I personally have always had the idle and cruise regions higher. now I wonder if I should go more
Yup ...that's exactly what I was thinking too .

I really think we now have enough information to make some good calls about oil injection/premix/Sohn strategies for various situations.

Last edited by Brettus; 12-04-2018 at 03:50 PM.
Brettus is online now  
Reply With Quote
Old 12-04-2018, 03:56 PM
  #65  
Registered
iTrader: (1)
 
FazdaRX_8's Avatar
 
Join Date: Jun 2009
Posts: 2,018
Thanks: 0
Thanked 4 Times in 4 Posts
could you make another graph but at 1krpms (idle) and another at 4krpms (cruise)?

also is there much talk about pressure? if there is only about 40psi of pressure and we are boosting say 15psi, doesn't that mean we are getting less oil, due to the effective oil pressure being 25PSI now?
FazdaRX_8 is offline  
Reply With Quote
Old 12-04-2018, 03:58 PM
  #66  
Registered
iTrader: (1)
 
FazdaRX_8's Avatar
 
Join Date: Jun 2009
Posts: 2,018
Thanks: 0
Thanked 4 Times in 4 Posts

COBB Turbo OMP Map
FazdaRX_8 is offline  
Reply With Quote
Old 12-04-2018, 04:02 PM
  #67  
Registered
iTrader: (1)
 
FazdaRX_8's Avatar
 
Join Date: Jun 2009
Posts: 2,018
Thanks: 0
Thanked 4 Times in 4 Posts
bassed from your 9k graph there is little to no change from 3-9 on the settings and 21? seems to be when the larger pump begins to flow.

seems like cruising should be 21 at minimum?
FazdaRX_8 is offline  
Reply With Quote
Old 12-04-2018, 04:18 PM
  #68  
Boosted Kiwi
Thread Starter
iTrader: (2)
 
Brettus's Avatar
 
Join Date: Apr 2006
Location: Y-cat-o NZ
Posts: 18,182
Thanked 201 Times in 154 Posts
Originally Posted by FazdaRX_8 View Post
could you make another graph but at 1krpms (idle) and another at 4krpms (cruise)?
?
the graph at 1000 is just 1/9th of the output of graph at 9000

Originally Posted by FazdaRX_8 View Post
lso is there much talk about pressure? if there is only about 40psi of pressure and we are boosting say 15psi, doesn't that mean we are getting less oil, due to the effective oil pressure being 25PSI now?
It's still a positive displacement pump ....so irrespective of the inlet pressure boost pressure shouldn't affect the output .
Brettus is online now  
Reply With Quote
Old 12-04-2018, 04:32 PM
  #69  
Boosted Kiwi
Thread Starter
iTrader: (2)
 
Brettus's Avatar
 
Join Date: Apr 2006
Location: Y-cat-o NZ
Posts: 18,182
Thanked 201 Times in 154 Posts
Originally Posted by FazdaRX_8 View Post
bassed from your 9k graph there is little to no change from 3-9 on the settings and 21? seems to be when the larger pump begins to flow.

seems like cruising should be 21 at minimum?
21 is my best guess as to when the larger pump starts to flow ..... it's going to be close to there. And it looks like output approx. doubles between 3 and 21. Doubling the output at idle and cruise seems a little excessive to me but ..........maybe not.
Brettus is online now  
Reply With Quote
Old 12-04-2018, 08:51 PM
  #70  
New Member
 
Join Date: Sep 2018
Location: Fort Myers FL
Posts: 2
Thanks: 0
Thanked 1 Time in 1 Post
Freaking genius. Probably some of the best information on here.
Tonycar107 is offline  
Reply With Quote
The Following User Says Thank You to Tonycar107 For This Useful Post:
Brettus (12-04-2018)
Old 12-06-2018, 09:08 PM
  #71  
Registered
 
kevink0000's Avatar
 
Join Date: Sep 2017
Location: Arizona
Posts: 74
Thanked 6 Times in 4 Posts
Brettus,

Well now we have more to think about with this ^^@#$%^#$% OMP!

So, the info you forwarded is convincing to me, even though it is anecdotal. I think the racer's opinion based on the amount of oil used in race conditions is worthy of note, because output at maximum should not vary much at all, certainly not by a factor of 2 or even 4. That is assuming the injectors themselves are unclogged and functioning properly, which I would assume is something a racer would confirm, especially in light of numerous premature engine failures.

So, assuming the lack of oil seen on the track is from the gravity feed nature of the Sohn, some questions:

Did he get oil pressure from a blockoff block BOTH OMP oil holes in the front cover? From what I can see, the OMP is located in a "stream" of oil, and it has an intake and outlet. One hole on the front cover actually feeds the unit, the other is a drain back into the front cover again. If I remember correctly, the feed hole is the one next to the drive, and the drain hole is the other one farthest from the drive. I could be wrong on this, but my circuit explorations led me to believe this was the most likely layout. Again, I could be wrong! So, there may be 40lbs of max hot oil pressure if "deadheading" both holes, but it would be nice to know if his apparatus had one hole open to the rest of the circuit in the same fashion as the pump, and what pressure the OMP is actually seeing, as a flow through device in the main circuit.

The Sohn tubing itself can easily flow 2lph (your max output calculation at 9k rpm) but the internal diameter of the OMP feed circuits themselves may not. I will use my test stand to see if there is enough leakage through the unit to safely accommodate this amount of oil feed through the pump chambers with just a gravity feed. I suspect this is not the peak output determiner though.

I think out previous conversation about "OMP valve float" may have resurfaced here. If I use your excellent research, I estimate that the big pump in the OMP body strokes at a rate of 14 times a second at max engine rpm. That is mighty fast for that small return spring to keep the pump body on the drive cam in the viscous environment of the OMP internally. It must have "help" in the form of intake head pressure, to bring the pump body back to the cam quickly for the next stoke. This, I feel would be the main obstacle in the OMP giving full output at high rpm with a gravity feed. And why it does OK on the street, or even in some track environments, because it can achieve full output at lower rpm, but begins to float at higher speeds. Just a theory.

I plan to add a small pump to the Sohn intake on my car, maybe 10-15 psi. I will run on the test stand first, just to see how it reacts with the OMP.

I want to keep running it on 2 stroke oil only,(not in the oilpan.) hence the feed pump proposal and I do want to keep the OMP working in conjunction with premix. I am unabashedly in the More Oil Everywhere camp with this engine.

Brettus I know you are premix only, I was wondering whet you thought of Eric Meyer's findings on his race cars regarding side seal spring failure and running the OMP with premix to avoid this. His posts were pretty convincing I thought, and make sense from a practical standpoint. Mazda focused the omp nozzles on the S1 and S2 to the sides for a reason, vs non-Renesis designs.

https://www.rx8club.com/series-i-tec...-210194/page6/




I am open to anybody's input/discussion on this, as I am still trying to fully understand how this thing works.
kevink0000 is offline  
Reply With Quote
Old 12-06-2018, 10:45 PM
  #72  
Boosted Kiwi
Thread Starter
iTrader: (2)
 
Brettus's Avatar
 
Join Date: Apr 2006
Location: Y-cat-o NZ
Posts: 18,182
Thanked 201 Times in 154 Posts
Originally Posted by kevink0000 View Post
Did he get oil pressure from a blockoff block BOTH OMP oil holes in the front cover?
.
I don't know ,but ........ If you have a look at the exit/drain hole at the driven end of the omp driveshaft you will note there is a small metering orifice there . There is another orifice at the end of the omp drain circuit in the front cover also . It's safe to assume that you can't block up the supply of oil to the driveshaft orifice given the way it's designed . . So .... given that only one of the two exit orifices could possibly have been blocked and would have low flow anyway........ it should make very little difference how he measured it.

Originally Posted by kevink0000 View Post

Brettus I know you are premix only, I was wondering whet you thought of Eric Meyer's findings on his race cars regarding side seal spring failure and running the OMP with premix to avoid this. His posts were pretty convincing I thought, and make sense from a practical standpoint. Mazda focused the omp nozzles on the S1 and S2 to the sides for a reason, vs non-Renesis designs.
.
Just had a read (pretty sure i read it years ago as well but had forgotten about it). I'm not overly concerned with premixing only as my engine wont see anything like the same conditions . Lower rpm and lots more fuel/premix . Might be worth considering if i am to do any long stints on a racetrack though.

Last edited by Brettus; 12-07-2018 at 03:01 PM.
Brettus is online now  
Reply With Quote
 
 
 
Related Topics
Thread
Thread Starter
Forum
Replies
Last Post
DMaverickRX8
RX-8 Parts For Sale/Wanted
9
01-30-2014 06:35 PM
BlackStealth
RX-8 Parts For Sale/Wanted
7
02-22-2013 08:46 PM
John Magnuson
RX-8's For Sale/Wanted
4
12-23-2008 02:46 PM
snkpkp
Series I Tech Garage
14
12-16-2008 12:17 AM


Thread Tools
Search this Thread
Rate This Thread
Rate This Thread:
You have already rated this thread Rating: Thread Rating: 1 votes, 5.00 average.

Quick Reply: OMP Oil Metering pump output and modification


Contact Us Archive Advertising Cookie Policy Privacy Statement Terms of Service

We are a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for us to earn fees by linking to Amazon.com and affiliated sites.