TeamRX8

iTrader: (25)

Other than your wallet and you don’t *have any clue* if it does either harm or good; just a gut *muh feelin’s* notion. I also prefaced that so not sure why you want to muddy the water with a cat converter comment.

if you’re gaining premix oil in the sump then the obvious reason for that is excessive blowby ...

just a reminder that the Renesis; while similar, is not a 13B ...

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Brettus

iTrader: (2)

I don't think that's it, the engine is quite new and has done that from the start plus there are no signs of blowby from the catchcan. I think this actually happens to all 13b engines that run a high concentration of premix oil in the fuel.

Have you ever run your engine on 100% premix ?

kevink0000

In my opinion the Sohn allows a cleaner burning oil to be injected, rather than motor oil which leaves deposits many times more in quantity and severity.
Many modern high quality 2 stroke oils are designed to be used effectively in new injector systems which restrict the oil amounts due to emissions, like our cars do. (600:1 in some cases!) (Polaris, Bombardier) So, maybe there is benefit there, with a modern 2 stroke formulation.

In my experience, there is much more difference in formulation and effectiveness between brands on 2 stroke oils than with 4 stroke crankcase oils. The old adage, "oil is oil" is much less true with 2 stroke oil than with 4 stroke oil. I don't subscribe to it in either case, personally, but especially with 2 stroke oil. The manufacturers have more leeway to formulate as desired with 2 stroke oil.

But, the main reason I like the Sohn is not the feel good aspect, it is that I can inject an oil of my choice in the quantity I desire and not worry as much about carbon and smoke. The cleanliness or the temperature is not as important.

The oil creep is from blowby, correct, but it evidences itself more at rich oil mixtures and low throttle positions, like for street driving. It doesn't mean there is anything wrong with the engine. Racing is a different matter. There is less opportunity for the oil to get pushed into the sump since more of it is being used up in the chamber.

Run a two stroke piston engine at low throttle openings for a while at 32:1 or 50:1 premix, and you will find unburnt liquid oil coming out the exhaust. Run the same engine and the same mixture in a roadrace of equal length, and you will only see powder and ash at the exhaust pipe, no more liquid oil. The premix mixture and the power level matters most in my example (not engine condition) , just as it does in Renesis "sump creep", in my opinion.

But, I agree with Team, the number of injectors and position is not the "fix" for these engines. They need a greater quantity of oil. He is right on the money in my opinion. The delivery method can be debated, but the quantity is the key.

Also, many times people on here will say there is no "scientific proof" that premixing helps/hurts, the Sohn is good/bad. etc. You don't need to use the "scientific method" to decide what to use in your car. You can use your 5 senses, combined with the sixth sense: Common Sense. You drive a car that historically (anecdotally, if you must.) loses compression rapidly compared to a piston engine. This engine also happens to partially employ a total-loss lubrication system. This engine also, when torn down, shows sealing surface wear from excessive metal to metal contact, at relatively low mileages. Many parts cannot be reused effectively in a rebuild because of this. You can do that math in your head. You don't need the scientific method or a computer model to tell you what might benefit and lengthen your ownership experience.

UnknownJinX

As a student working at a data analysis job right now, I am not fully convinced.

When I do data analysis, I can notice trends as well, but my mentor tells me to be careful with them. Just because a part fails often in the summer, doesn't mean the heat necessarily caused it since there are many other variables at work here, and these conclusions will be seen by the higher-ups and things can get complicated.

In the case of RX-8s, we also know that early RX-8 coils are terrible and don't do a good job igniting the air and fuel mixture after a while. The fuel can wash away the lubrication and plug the cat, which are also detrimental on the engine seals. Add that to the supposedly subpar remans in the past, there are just too many variables for anyone to comfortably make a conclusion like that.

At best, you can say that more lubrication may help with engine longevity.

Also, oil affects cat health. IMO running catless or not is choosing between your own health and engine health.

kevink0000

I knew the scientific method conversation would bring some people out! Not trying to start a conflict, but also want to give some ideas to owners who might not try different things because they are not "proven" by "science", and challenged on here by well meaning folks who say "there is no proof that.." For many that means don't do it. I think differently.

The difference is looking at trends, statistics, numbers, and (dreaded, my opinion) computer models are all very useful. But not infallible. And not the only thing.

I am talking about looking at the inside of engines, and holding parts in my hand. I can think. I can make conclusions that dictate my choices based on that, very comfortably. And, with good results over the "small sample" of my lifetime.

Experience is after all, experience.

TeamRX8

iTrader: (25)

I have one of the first sets of the new then i-Rotary (Iannetti) steel apex seals (RX7 type) that I was going to use in my washed-out turbo build and they recommend 2.5 oz per gal minimum. Racing Beat ran 4.2 oz per gal in their 600 hp 2-rotor 13B turbo. They tested and recommended heavier than that for NA Renesis track racers. Not that everyone should do that, but you guys don’t seem in touch with some of the data out there. Just like the people back when that swore premix rather than OMP would kill a Renesis in short order. Well that was false, just like the engine builder who has been doing this almost 50 years told me. The same for all that S2 engine marketing malarkey we went though for years and now all the failed engines can’t be denied.

you’ve been lurking on here since around what; 2016? You have experience, but what exactly is it and what’s it really based on? Experienced sailors 500 years ago sincerely thought if they kept on going they’d fall off the flat edge of the earth. Now people scoff because they think everyone with a brain knows that the world is round. Yet they’re blind to their own ignorance over so many things thanks to that proud, vain, and arrogant mindset. A person only knows what they know, yet they don’t put much consideration into what they might not know yet that proves their prior or current thinking to be wrong, ignorant, etc.

kevink0000

Team,


I am not talking about my experience as being paramount, which I guess you got as the impression of my post. In my opinion, I know very little, that's why I am on here as often as I am. If I knew all of what I needed to know, I wouldn't be here, most likely. I have pulled apart a lot of engines, of many kinds, and there is a theme with the Renesis failure mode that I think is undeniable and obvious.

With "data" or not, you can observe problem areas and make determinations. I know this may sound shocking to many, (maybe not you) but you don't need a huge sample! So I stated that. I am talking about people getting their own experience, and making their own decisions, based on what is between their ears. And Internet Experience is not really what I have in mind.

Race builders do this, with one engine or maybe at most a sample group in the single digits. They don't break 1500 engines to gain a "meaningful sample size" to be loaded into a computer for analysis before testing a theory as to why this part wears, or why it needs more strength, etc. They would not win any races. Even large factory race efforts don't do this. They see a wear or breakage pattern on one or two engines and endeavor to fix it. I think this is my point. It is used in the real world and works. When did we get away from this?

I seek other's knowledge and everyone should, and gain as much as they can from it. What my post was directed to was people who state that there is no "scientific" proof, etc, so therefore you shouldn't do this or that. Honestly, some of the things you say sound like that to me. People can prove a lot of things to themselves, by opening an engine. Any engine. Especially failed ones. I am sure you have, and that's why when you post I will read your posts, because I learn from you. You have spun wrenches and made mistakes, and learned from them. Hopefully you understand my meaning. I disagree with some of what you say, and will gently state my contrary case so that others can weigh it, and we can hopefully discuss it. That's why people come here, to get info, hopefully the sum of which is good info.

kevink0000

Spartan,
Regarding your overclocked pump that throws codes:

It is possible to set the idle stop screw too far into the sector gear travel, and have the motor run the gear off the end of the travel and not be able to re-engage back to less than full throttle. This will throw a code. My impression of the OMP readiness test that the ECU does, is that it runs the OMP to idle, and then runs it up to position 60, to make sure the switch on the OMP gets triggered. The ecu can read the 0 position, and can read the switch throw at or near 60. That's all the feedback it gets. That's why the overclocking works to increase oil rate without the ECU "seeing" it.

Have you pulled the cover to check the sector gear position? If its at full throttle from the last time it was installed, I would say you found your problem. The ECU returns the OMP to idle at shutdown. You have to make sure the sector gear is always engaged with the motor pinion at full throttle, based on 60 steps from where you have the idle screw set. Then you adjust the switch to accommodate the new travel range you have set. I found that each motor "step" was worth about 2 steps that the ECU would see, so I used that method (30 motor steps) to count up to 60 and set my idle screw based on that.

If your second non code throwing pump has the big piston mod but no clocking, then something may be amiss with the assembly or modding of that pump. I saw immediate results of larger oil injection with the larger pump installed, and then a very large difference with the clocking mod done.

Hope this helps.

spartantrap

Apologies for the long reply....

Regarding warm/hot vs cold oil. Somewhere in this thread, or the overclock thread, I read that the OMP does actually see some positive pressure (around 5psi?) from the oil pump. I'm personally not convinced that a Sohn adapter is best gravity fed. I'd like to actually like to install a small pump to provide about 5 psi of pressure to the OMP if/when I get a Sohn. At that point, the warm vs cold oil point is moot

Which I know there's no evidence either way. That doesn't really bother me. I would like to inject oil that burns cleanly though, but at a much higher rate; because this stupid engine loves it (at least in my own experience)

Now what was that about cats? rotaries kill cats, it's just their nature; and cats in turn kill rotaries. Quite the vicious cycle. I put an end to that cycle in mine

Which is more than likely what's happening in mine. It's just more evident now that the overclocking is gone

Heh... what cat...

Blowby even on a reman with less than 7k miles put on it?... hmm....

One thing though, it is a 13B. It's just not an REW, it's an MSP. And I read that the REW guys get oil dilution too so they had to up their oil change intervals to 1.5k miles just to keep their viscosity. My experience seems to congure with that

Again, my experience is in line with what you're saying

I chose engine health lol

And yes, there are many variables at play. I'm just trying to mitigate said variables and adapt one thing at a time and watch the trends

So how much should actually be premixed? And is that premix with an OMP or straight premix? If Racing Beat recommends more than 4.2 oz per gallon, I'm curious to know what the number is

I'm pretty sure that's what happened when I initially did the overclock mod. Unfortunately I disposed of the pump.... so I'm not able to do anything with it.... poor 4th dimensional thinking on my part

I appreciate the info on how the computer reads the sensor. If I had known that when I had modded the previous pump, I likely wouldn't be here lol

Now when I was diagnosing the issue, I did have the cover off and turned on the key so I could watch the travel of the saw blade. I did observe it swing off of the motor, so there's that. The weird thing is that I didn't have any issues for about a month and a half; then it threw the code randomly after I had stopped by a friend's house for like 5 minutes. It still weirds me out

I don't believe there's anything amiss with this current OMP. I'm thinking I'm not seeing the oil level drop as fast because of how heavy I actually premix. My estimation for where my gas gauge is and how many gallons it takes to fill up is generally over by about 1 gallon; so it's typical for me to premix 11oz into 10 gallons. Which as discussed earlier, tends to lead to "sump creep" (as they called it), which my overclocked pump mitigated/prevented

I just need to purchase two more OMPs to mod into the big piston/overclocked; that way I have a known good spare to throw in, in the event that I F'd it up

Red line envy

My rebuild has never had an omp hooked up. I've been premixing at 14 oz per tank and iv put over 5000 km on it so far. With no RELATED problems.
no cat, ms intake and bhr coil kit. I have no blow by or any oil dilution.

kevink0000

Spartan,

The OMP oil output from the front cover to the OMP is probably not pressurized at any point. Earlier in this thread, an ambitious RX8 owner posted a you tube video of the OMP oil output hole on the front cover with a pressure gauge hooked to it. At all RPM, including near redline, there was 0 pressure. The oil flow to that hole appears to me to be a return artery that also flows through an air/oil separator box. His video is consistent with these observations of mine:

My Sohn and OMP flows a great amount of oil, with gravity feed. At high rpm, high throttle use it seems to increase exponentially, like it is supposed to.

The air/oil separator Mazda engineered into the front cover would not work properly if the oil or the separator box was under pressure.

The design of the OMP, while updated for this car, is consistent with earlier mechanical Mazda OMP designs, which are identical in function with motorcycle and powersport injector pumps I am familiar with, all of which used gravity feed only, a few with higher power output per liter than the Renesis. Most were made by Mikuni also, just like our OMP.

Brettus has different info on this, and he and others may chime in, but I personally am almost 100% convinced that the Sohn with gravity feed will produce the same output parameters from the OMP as if the OMP was in its stock position on the front cover with the normal oil feed.

So, you don't need to add a low pressure feed pump with a Sohn, in my opinion.

spartantrap

Hmm... I've had to think about your response over the last few days. Which is what took so long:

I see what you're saying about not needing a low pressure pump. So, I'm not really worried about it anymore, but it'd be an interesting test to try

Now, I've decided to hoon my 8 more than normal and my oil consumption seems to have gone back up. I'll be needing to fill up tomorrow and I'll be checking it again and reporting back

sinkas

fro a very casual observation I have noted that engine builders here,
say that they see alot more glaze and buildup in engines that have had heavy 2 stroke than those with stock OMP,

kevink0000

I would say that runs contrary to what 2 stroke oils' primary purpose is. To lubricate and burn cleanly. However, I have seen some posts about a "glaze" or "gum" but that I believe is for the castor blends, which are not recommended unless you are running alcohol. I have run castor compounded oils in 2 strokes, and try to avoid them now for that reason.

spartantrap

Got any 2 stroke oils that you recommend? I've strictly been using Idemitsu so far

My oil consumption seems to have gone up with flooring it more, but I still need to get a couple more OMPs to mod; that's going to have to wait a bit though... unfortunately

wannawankel

The cheapest JASO-FD rated stroke. Menards and Ace carry Mystik Sea and Snow JASO-FD for $16/gallon! Just make sure it is NOT TCW-3 rated - that's not what you want. JASO-FC or -FD are clean burning for 2-stroke and RX applications.

kevink0000

I have not come to a 100% conclusion as far as 2 stroke oil. I have used Maxima Super M injector both in the OMP tank and premix, for about 30-35k miles. I decided for economic reasons to go with Amsoil Interceptor. So far I notice less plug deposits and better exhaust smell. I have a "test" that I like to do, which I wont get into here, and the Amsoil does better in that test than Maxima did. I did not like Lucas, FWIW. It seemed to burn less clean than either Idemitsu or Maxima. The Amsoil is the cleanest burning that I can tell. Yes, they were all rated the same.

TeamRX8

iTrader: (25)

It makes zero sense for you to be using Amsoil Interceptor rather than Amsoil Saber Professional. It’s hard for me to take any of this any more seriously now than 10+ years ago.

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RIC SHAW

So boost wont force the oil back down the feed lines to the pump?

Loki

iTrader: (1)

It doesn't in the FD and other stock boosted engines, and the OMP is basically the same. Plus the pump would have to turn backwards for anything to go down the lines the wrong way, which isn't going to happen.

kevink0000

The check valves in the banjo bolts prevent reverse flow, the pump does not. The pump is not sealed well internally.If it is subject to both pressure or vacuum at its outputs, its output profile will change drastically due to those factors.

Again, if you take a pump off your car, and examine it, you will see the reason Mazda put the check valves there, as well as the airflow system from the injectors to the intake tube.

In an NA car, the banjo bolt check valves keep oil in the lines at shutdown. There was a Mazda paper on this somewhere. It would leak back if this wasn't present. I assume in FI they would prevent boost from pushing oil back down the lines, but I have no direct experience with that.

The check valves in the injectors and the airflow system keep vacuum from presenting at the oil output lines, and sucking oil out of the lines due to vacuum. This system probably provides some measure of atomization of the oil, since air and oil is going into the chamber through the injector at the same time. There was also a Mazda paper on this as well. I wish I could find it.

Mazda put these "extra" parts in because the pump can leak internally. You can suck oil from it through your mouth if you like.

TeamRX8

iTrader: (25)

mmmmm ... used motor oil infused with fuel hydrocarbons

kevink0000

Don't knock it till you try it. Depending on the oil brand, you can get some pretty good flavors. Almost like Starbucks.

kevink0000

Old Mazda lit, looks like from FC days. Mechanical throttle linkage.

TeamRX8

iTrader: (25)

why don’t you just use the RX8 documentation instead?