This question is exactly what the whole premix choice hangs on, and exactly what the test does nothing to resolve. The short answer is "we don't know", even after that test.

Burning affects different chemicals differently, and even with a single chemical, they don't behave the same at widely diverging temperatures.

Aside from lab controlled testing inside a combustion engine that was torn down repeatedly to measure results (like bse did, though I'm sure it was his garage ), about the only way of actually testing this that I can think of is building a gasoline fueled blowtorch so you can set the burn to the actual AFR of the combustion, and add the premix oils into the fuel stream while the flame is torching onto each of aluminum, iron, and steel (all 3 metals are present in the engine). Examine the surface accumulation after each premix has been tested on each metal. Even that will be difficult to stay controlled between each premix.

Part of the problem is that gasoline is FILTHY by itself. Pour ~3-4oz of gasoline into a small jar, like a baby food jar, and light it (obviously be smart and safe about it). The gasoline burn will leave an encrustation of carbon around the inside of the jar, especially heavy just inside the top. I did this once with about 15oz in a larger apple sauce jar once, and there was about a quarter inch of carbon built up around the inside of the top edge by the time the gasoline finished burning out.

Granted, it's hardly a controlled burn in terms of air/fuel ratio, and that will make it worse, but still, it's pretty compelling to see how much carbon can be left behind by gasoline alone.

Now to compound this even further, pics from 9krpmrx8's last engine teardown shows that his clean 2-stroke oil was actually protecting the rotor from carbon buildup along the edges where the oil injectors sprayed. So clearly some oils will actually help to prevent buildup as well.

 

Less residue isn't the only thing you should desire from your premix... Pettit's premix isn't rated. FC, FD, and ISO oils go through vigorous tests in order to be approved as such an oil, and they have amazing lubricating properties.

You can have a clean burning premix oil, but the main question is... Is it doing it's job as a lubricant?

I'm not trying to put down Pettit's oil, but they're not approved by any of those ratings. It doesn't necessarily mean it isn't good, it could be for all I know and I'm sure it is.

 

How was I being a dick? I am just trying to help you see thru the marketing BS.

 

So ultimately on average what oil do you guys run since about 20+ have been named.

 

Pressure also plays a role in how things burn and what they leave behind

Motul 710 is my premix of choice.

 

Any good JASO FC or FD equivalent 2 stroke should be fine. I run Idemitsu (JASO FC equivalent but not rated), but only because it is easy to get by the case and because it is the only one designed specifically as rotary premix.

But there are many options. Academy Sports (local sporting goods store) has Mystic brand JASO FD brand synthetic 2 stroke for like $12.00 a gallon. That is what I use when I run out and forget to order a case of Idemitsu.

 

amsoil ... in the words of ronco ... "[pour] it and forget it"

 

You could also just buy a bunch of different brands and test them on a frying pan in your kitchen and see which one does better

 

After reading through this forum I'm STILL lost as to whether or not premix is a requirement. My 8 has 78K on it currently and it's on the 2nd engine. Should I premix or just not even bother?

 

The short answer is "yes".

The long answer is:
Yes, premixing does indeed help to protect against engine failure. However, premixing will in no way ensure your engine's survival, just like exercising regularly won't do anything to prevent getting run over by a bus. There are so many ways that this engine can fail, and premixing only addresses one of them (apex seal wear), possibly can help mitigate a 2nd (carbon buildup). Plenty of people opt to not premix because they figure it's just going to be wasted, believing that something else is going to kill the engine before apex seal wear will.

Like a heroine addict not bothering to consider lung cancer from smoking, because mainlining heroine is probably going to kill him before lung cancer shows up anyway.


This engine is all management of the risks, and knowing that there is no fail-safe, no perfect solution.

 

@RIWWP

Very good summary/conclusion, which I agree.......
BTW........I premix since new.......

 

Thanks for your feedback! I am now "Claritin clear" . I think I'll just monitor my oil consumption regularly and change my oil every 3K. I have no issues with a redline daily so I guess I'll just take my chances by not pre-mixing. Thanks again!

Anthony

 

Note that I advocate FOR premixing. I don't see the value in ignoring that risk. I also advocate addressing every single point of failure and managing the risk as much as possible. I don't see premixing as worthless.

 

I would only consider pre-mixing worthless if you do not plan on keeping the car/engine much more than a year or 2, or you have a large chunk of your warranty left and you are trying to kill the engine to get a new one before it expires...

 

Thanks yet again for your feedback. However, I never said that premixing was "worthless". All I was saying is that I think I'll be okay not premixing since I don't race or anything. Basically.....from everything I've read on here is that y'all are saying that the Mazda stock OMP is not sufficient for a stock 8 and I need to premix to extend the life of the rotors and housing alone? With that being said and say I decide to go ahead and premix, Idemitsu right? Thanks in advance.

Anthony

 

I actually just had a compression test done yesterday b/c my warranty expires middle of April. I had to know so I went and paid for it ($100). The following results came from the dealer I took it to:

R1: 7.9,7.9,7.7
R2: 7.8,7.8,7.7

So with that information.....I have no intention of getting rid of my 8 and I want to keep it as long as I can. Oh by the way, I bought this car used and it's on its second engine from previous owner who ran it until oil light came on.......moron. Anyway, thanks for chiming in. I appreciate any and all feedback.

Anthony

 

We share similar stories.

Bought mine used, with 89k on the chassis, and 42k on the (3rd) engine. Had about 9 months left on the warranty.
Got a compression test from Mazda with almost the exact same numbers you have.
After the warranty expired, I started doing home compression test to monitor the health of the engine.
I sit right below Mazda min spec with almost 70k on the engine now. No engine issues yet, starts right up hot or cold, can get 22mpg hwy and between 14-17 all city with a/c. Been premixing since the first tank. I've also premixed my 3 rx7s and not a single engine failure yet. (knock on wood)

 

I'm from Alexandria, LA for the record. I'm in the Marine Corps and stationed in Virginia. Anyway, what do you premix with, what ratio, and do you premix prior to filling up or just pour directly into an empty tank.

 

Lol. As many times as you like. I'm familiar with the MSDS, etc...

What exactly are the lubrication requirements of the seal/housing interface? It's a black art, afaik. Hence the endless debate. Note that the MMO is not behaving alone, there is already an OMP delivering lubrication. I view MMO as a supplement/additive. It doesn't have to carry the lubrication burden alone, whatever that even IS. And I'll note that MMO was originally intended both as a cleaner and for top-cylinder lubrication. A task that is somewhat similar to lubricating the seal/housing interface.

 

top cylinder lubrication has got nothing to do with apex seal lubrication.
Think about the 2 oil nozzles as an anti chatter device for the seals and premix as the all around lubricant.

The lubrication requirements of a seal\housing are the same of a 2 stroke engine. It's as simple as that. You have to reduce wear, friction and avoid deposits.

 

top cylinder lubrication has got nothing to do with apex seal lubrication.
Think about the 2 oil nozzles as an anti chatter device for the seals and premix as the all around lubricant.

The lubrication requirements of a seal\housing are the same of a 2 stroke engine. It's as simple as that. You have to reduce wear, friction and avoid deposits.

 

Currently using Amsoil saber pro, 1/2oz per gallon (6oz per fill up from the 1/4 mark on the gauge). I just pour it directly into the tank, prior to filling up. You might want to go with a slightly lighter mix if you still have a cat. I've also used my CobbAP to increase the oil injection rate of the MOP.

Thanks for defending our country sir.

-Shawn

 

pretty small bottle.

got two of them, am planning to put 3-4 oz on every half tank.

thank u my rotary family

 

i use idmitsu premix. 8oz per tank. some use proteck. that **** you posted i would put in my weedwacker

 

anything thats easy to get in stores?