peejay

Gasoline is not a single chemical, it is a blend of all sorts of different hydrocarbon fractions and other things. You don't have to worry about gasoline "settling out", right? Adding oil to the gasoline is the same principle.

If only the oil and gasoline WOULD separate. I wouldn't have to change my oil so much, just siphon the gasoline off the top

j9fd3s

iTrader: (3)

you should hook the OMP up, to the gas tank....

Barry Bordes

The Apex seal itself is the critical component as far as oil quantity is concerned.

And more specifically.... the center portion that goes over the exhaust port and spark plugs (non-side port exhaust RX8).

Here are some Mazda results.

....... So the location of the oil introduction port is no accident.

The question you have to ask yourself is ... how much oil will this middle portion of the apex seal see with my premix quantity?

Barry

peejay

My engine? I'll feed it all the premix I can! If it hurts octane then the solution is better fuel, not reduced oil.

Another thing that I found was a research paper on premix quantities for 2-stroke engines. Besides noting increased power output at higher and higher quantities of oil, they also noticed a lag effect with respect to the output effects. The paper is on another computer, and I found it buried deep in the archives on eng-tips, but the takeaway I got from it was that the power effects were only noticable after running the engine on the new mixture for a while. This lag worked both ways. Meaning, after running at 1:10 fuel/oil, they would go back down to 1:20 and the engine would still make the higher power for a few minutes of dyno time. Theory: The oil needed time to saturate the cylinder walls before power effects could be noted, and likewise needed time to desaturate after the oil was removed from the fuel.

This was on an iron-bore piston engine, not a porous-chrome lined rotary.

So: On the street, where you are at idle/low load for 98% of the time, you can get away with premixing insufficient for max load, because you will be "pre charging" the chrome for the 2% of the time you will be under high RPM/load. But, if you plan on running it hard at a higher duty cycle, then you WILL need to premix more oil.

I remember a blurb in one of the old Racing Beat catalogs where they mentioned running upwards of 4-5oz per gallon on high powered endurance racing/LSR engines. Food for thought.

edit: It made it to the website: http://www.racingbeat.com/mazda/perf...lters-mop.html
I remember when the RX-8 was new and Judge Ito got one, and he did some "simple, non invasive" things to the car and was running high 13s in the quarter, and he ended up being censured by Mazda and all references to what he did were removed from various forums. I strongly believe that what he was doing was adding a ton of premix, given not only my experiences with "excessive" oiling but also the 1st-series RX-8's notorious insufficient oiling to the engine. And reducing oil consumption is necessary to keep the cats happy, adding tons of oil will reduce cat life dramatically, and Mazda didn't want people burning excess oil and killing the cats which they would have to replace under warranty... But I have zero evidence, just theories.

Barry Bordes

On two-stroke motors we always found about a tablespoon of oil in the crankcase when what they were disassembled. This caused them to smoke rather heavily when starting a cold engine (and the normal time to foul a plug on early ignitions).

Under normal operation what actually happens is that the fuel evaporates in the hot intake track and leaves the oil to be plated out against the walls.

That is why it took a while when you made your new leaner or richer mixture run for it take effect.

So the intake ports, side seals and and corner seals will all get a good dose of oil. Even the ends of the apex seals get a good coating.

The problem is getting the oil to the center of the apex seal where it is hottest and need most. How can we do that?

It would work well with a peripheral port... But side ports not so much.

Barry

t-von

iTrader: (8)

^I think that's why it's a good idea to run both the omp and premix for that reason. Personally, I love how premix keeps carbon build-up down on the rotor faces. Plus the oil film travels way up the intake runners and helps keep the aux and vdi actuators nice and loose.

DeaconBlue

iTrader: (31)

Just to update an old thread encase anyone does any searching...

I am switching my S5 OMP over from the factory crank case oil feed to a remote 2-stroke oil tank feed via the Aviation Rotary kit and I am upgrading to the Lucas semi-synthetic 2-stroke oil, most due to it being; TC-W3, ISO-L-EGD and JASO FD rated.

Semi-Synthetic 2-Cycle Oil

It is easy to pick up since it is a normal shelf stock item at my local O'Reilly's Auto Parts stores.