Brett,

I really can't say what will work for your setup, other than maybe the actual oil type is not best for your fuel when using omp. I believe you were using crankcase oil, and that may be the only issue when you switched fuels. I have read that the guys who run heavy alcohol fuel content here in the states use a castor based 2 stroke blend, because it stays in suspension in alcohol fuels longer than esters or other blends. This effect may also occur on lubricated surfaces within the engine as the alcohol washes away the petroleum based oil within the chamber. I think your problem may not be (only) oil delivery system here but oil type primarily.Crankcase oil is a terrible lubricant in my opinion in a total-loss system like we have.

If you could get a Sohn on your engine and inject a castor blend, I bet your results would be acceptable with the omp again.

I have found that premix rate directly affects oil blowby into the crankcase much more than omp injection rate does. I think there is a point in the combustion cycle that the fuel injectors really have good access to leakage areas on the side seal and oil seal systems, and the pressurized mixture goes through it in quantity. Fuel too, but that will evaporate to some extent. We have all heard about the modded turbo FD guys complaining about 10% fuel dilution in 1000 miles of running,and crazy stuff like that. That is not solely attributable to a worn engine in my opinion.

In my stock NA setup, I just run oil level lower when changing, so it has room to "grow" during the interval. If you look at my oil analysis submissions posted on this site, there is evidence
of oil dilution by oil. My choice of a thicker sump oil reflects this reality too. I bias my choice of oil toward getting the chambers a lot of lubricant, and what happens to the sump oil is a secondary concern. My wear numbers show pretty good results at this point, so I think I am satisfied with the compromises. I like the OMP, but just with greatly increased output. For you, i think it would be better, but the lubricant choice is very important. Redline and Klotz sell 2 stroke alcohol oils, and are talking about 12:1 or 16:1 oil ratios on their websites! Sounds to me like fuel type leading to oil type is your primary problem, followed by oil quantity. Model airplane oil is in your future!

Thanks Kevin , some good info there! I'm going to try 120:1 instead of 100:1 to start with and see if that slows down the level rise. Most of the REW guys run that for the street . I wanted to run a higher ratio because I think our exhaust ports need extra but I'll just do that for dyno/track day if 120:1 works out.BTW I'm already using Motul 2T micro, which is a model airplane oil ...so you are 100% on the money there !

Very interested to hear that you get an oil level rise now that you have upped the omp rate dramatically. I'm thinking that at low rpm/load the oil doesn't get burned off and accumulates in the chamber if there is too much coming in . then there is only one place for it to go ..... into the sump.

Brett,

Actually as I reduced my premix ratio, I was upping the OMP output. I reduced my premix ratio to about 1/3 of what it was before and saw an immediate and large decrease in "sump seep". I didn't measure it and its strictly anecdotal, but the premix was largely what was ending up in the sump, in my view. I am running approximately the same overall ratio approximately, combined with OMP and premix as before, just the OMP has the vast majority of the oiling duty, and my sump seep is much less than it was. So, my theory is that the OMP is much more efficient at delivering oil to the chambers, where it will leave via the exhaust port instead of oil seals. There is a lot of oil being burned in my engine, (by current standards), by my choice, and I now prefer the OMP to do most of the work.

It really should be included in this thread

https://www.rx8club.com/search.php?searchid=13452228

Brettus, I am curious on your feedback, I have attached the base map for the adaptronic OMP map. Trying to debate if modifying to match your map, or see what this map can do for me. Or just give you what adaptronic has decided upon. Granted I will not be tearing apart my engine to check, or is it a new motor.

https://cimg9.ibsrv.net/gimg/www.rx8...d9da1804f2.png


Regards,
Dustin

1. Are you running a cat converter?
2. Why do you have a low load @ 2000 rpm spike on “your” map

I was wondering the same. My assumption is cruising at in town speeds? I forget what rpm is at 35 mph.

Well you said you devised that map, but you don’t know why the spike is there? I can’t recall ever seeing that spike on any other map so I assumed you made it that way for a reason. :dunno:

That's Brettus' map.

That's actually on most of the early omp maps . I think it was to do with extra oil at startup as it doesn't correspond to any normal loads you would see at those rpm.

That map is using kpa instead of load and %? instead of 0-60 . I really couldn't say as I can't be sure how it relates to the stock map.

Interesting. I may have to add this to my map then. That could also correspond to when Mazda said to rev your motor before you shut it off.

Well I work mostly with Cobb maps and don’t remember ever seeing that spike, but it’s been quite a few years since I’ve opened them and may just be a personal fubar moment ...

Brett,

I just posted a UOA on the forum, and notced something that may be good to consider in your case. In between sample #2 and sample#3 on my UOA, I used much less premix, but increased the OMP output to a similar oil usage rate. Using the same amount of 2t oil, but having a higher bias in OMP rate, I saw less chrome in my oil, even with a longer interval, and much more high load near redline time in this sample.

With your Methanol related wear issues, maybe considering OMP use with compatible oil in conjunction ​​​​​​ with premix would help?
https://cimg8.ibsrv.net/gimg/www.rx8...ca2e2576f9.jpg
n with premix would help?

Can't see that in the numbers above , looks like all '1's to me..... not sure I'm looking at it correctly ?
Edit:
Did you mean aluminium ? That wouldn't be from the housings though would it ?

Yes the number is the same, but longer interval but a lot more stress on engine all through the interval. I was expecting it to show many times more PPM chrome, more in line with some of the other tracked car UOAs we have seen. Instead it was the same, which from a practical standpoint is less, if you know what I mean. :)

Ah ...ok . That makes sense . I've been considering some alternate options to what I'm currently doing because I'm using a shit ton of very expensive premix and a lot of it appears to be ending up in the sump. Would make sense to fire it back in via the omp ...kinda like a merry go round LOL

Exactly. A lot less goes into the sump with OMP.

I can imagine with FI fueling rates, coupled with alcohol fueling rates, and high premix ratios, you might as well put a fuel injector directly into the oil fill!
Holy cow! You are a true believer. Long live the Renesis!

heh ....
The problem as I see it is that you need minimum 100:1 for high boost situations , but for cruise it's probably more like 150+:1 and so I end up with too much going in at cruise and it doesn't all burn off, so gets compressed and shoots past the oil seals. What I don't know is .... if omp is working , how much premix can I take out and still be safe under boost . It's obvious from the failures iv'e seen that under boost with the omp functioning and no premix, the critical point for lubrication becomes the middle of the apex seals.
Heavy premixing addresses that but I suspect upping the omp output doesn't. It kinda makes sense to me now why the S1 omp injects soooooo much oil at wot . It's Mazdas' attempt at covering up the design flaw (later corrected with the S2).

Seems to me the solution is to try and premix for 150:1, back off omp injection in low load and crank it up in high load, or something along that line of thought.

Brett,

I am definitely no expert with FI, and I am going on a theory based on just my individual experience, but I think you will find that the issue with "sump creep" is not due to excess oil in the combustion chamber getting forced past the oil seals, under combustion pressure, ( even with FI), it is due to the fuel injectors having access to the side of the rotor at some point during the intake cycle, and spraying premix hard enough that it passes the oil seals.

I’d be more inclined to believe it’s just excessive blowby in general

That's what I used to think too. There is that also, for sure, and FI may change everything, but I almost have myself fully convinced of what I stated above. Almost.

being convinced and being correct are not the same thing.

Pretty much just like all the whacko nutjobs you see in society these days ... just sayin’ ...

Castor oil? Use of street or circuit?
I had always read that castor-based oils were not recommended for street use, as they left a lot of residue. I had read that is used in competition because it is very good, because in competition the engine is opened every bit to replace parts and clean while in a street use it could be a problem.