How much Premix do you guys run in your cars? No OMP of course.

 

i thought it was like 2 oz per a full tank of gas, i must of misunderstood the previous owner.

 

use the search button, this topic has been covered 10000 times

 

I found it. I'm a retard. I probably just half'ed the life span of my motor.

 

racing beat specifically says 3 oz per 5 gallons, more is unneccessary unless you are making MAD power. Also use quality synthetic or mobil oil.

 

i like castrol gtx 10w30 sae and amsoil synthetic premix 2 cycle 100-1

is that alright?

 

I went from ~220:1 to about 130:1 and noticed a slight torque increase. However, this was on an engine with Rotary Aviation apex seals that scored up my housings. My OMP is disabled, of course.

 

mine seems to run best at 100:1-80:1. i can tell its a little less smooth even at about 128:1.

 

If this is not coverd meany times. 100:1 with no OMP and 200:1 with OMP. My user name will bring up very good threads on premix. I sugest you read them.

I run royal purple 20w50 oil and 75/80 in LSD rear end with syncromax trany fluid.

 

Hmmm, interesting, I haven't experimented with sub 100:1 ratios, maybe I'll give it a try.

 

food for thought about premixing,, the more oil you put in the gas the more gas that is displaced, meaning if your injectors squirt a certain amount of gas , some of it isnt actually gas, so your A/F ratio goes very very slightly leaner then expected.

has anyone ever ran into this as a problem??

 

sorry, i dont know much about rx7's, i am a 4g63 expert....
so you put oil in your gas? am i supposed to do this? my Fc is just my daily driver, its a 88 n/a.

 

you have to add way too much premix to get it to actually lower the octane rating a noticable amount. this stuff was created to mix with gas and be conbustable, its not like you're adding chocolate syrup in with your gasoline or something.

 

2cycle engine oil, yes. about 1oz per gallon

 

No.


-Ted

 

Well he is not supposed to, if his OMP is working.

 

Im a FC noob. What does the OMP (oil metering pump??? i guess) do exactly? I used to own a 2 cycle 3 cylinder streetbike that had a separate oil tank for 2 cycle oil. It had a little pump that squirted oil into the cylinders or intake or crankcase somewhere so you didn't have to "premix" your fuel. But if the pump failed you were screwed. I know this is a ROTARY but lets talk PISTON engines for a minute. I know they are completely different but they do share similarities in the fact that they intake a fuel/air mixture, compress it, combust/burn it and then exhaust the new mixture. In a 2 cycle engine(at least the ones Im familiar with), the crankcase is part of fuel delivery/combustion system unlike a 4 cycle where the crankcase and the cylinder are completely separate. The 2 cycle needs the added oil to lubricate the wrist pin and the crankshaft bearings. Of course this added oil in 2 cycle engines is burned along with the gas. Does my FC have an oil tank somewhere like my old bike I don't know about? If not, then in factory condition, it was likely not intended to BURN oil right? Cause if it were, the cars would have warning stickers on the instrument cluster or around the gas filler cap, stating something about the mixing ratio or "remember to add oil", similar to the "unleaded fuel only" sticker we see so often. If it wasnt intended to burn oil then the car wouldnt deliver oil to the same places that it delivers fuel. And if thats the case, then why would you add oil to the fuel? Somebody please explain the OMP, and the purpose of premixing as it relates to rotaries..

 

*sigh* I have nothing better to do, so I'll rehash general rotary knowledge available in a variety of places.

The main engine oiling system (crankcase oil) lubricates the eccentric shaft and assorted bearings. There is no way for this oiling system to oil the apex seals normally, so for a while they didn't get lubricated. Then, Mazda realized that lubricating them allowed the use of smaller (lower drag and better sealing) apex seals, so they started lubricating them. On a street-going car, requiring people to mix the gas with oil, or fill a separate oil tank is unacceptable. You're lucky to get people to change the crankcase oil in a reasonable time period.

So, the MOP injects crankcase oil into the combustion chambers. There are injectors in the primary intake runners, as well as in the housings. They inject crankcase oil, which isn't designed to burn cleanly, and it lubricates the tip seals and makes things somewhat happier.

Problems with this system include the fact that crankcase oil doesn't burn cleanly and leaves a nasty carbon coating on things (old rotors are usually covered in carbon), as well as the fact that dripping oil in doesn't do a terrific job of oiling the edges of the apex seals.

Premixing is what Mazda does on all their race engines. Premixing is also what a lot of people (me included) do here. You remove the MOP setup, and mix 2-cycle oil in the gas when you fill up. Instead of dripping something not designed to lubricate a combustion chamber, you forcably spray something designed to lubricate a combustion chamber. It does a MUCH better job of lubricating the seals, burns cleanly (doesn't leave carbon buildup), and is better in every way except the slight inconvenience of filling up. It also does have the side effect of increasing oil dilution from gas, due to increased blowby from the combustion chamber, or the side seals riding on enough of a lubricating film that some can get past, or some other method, such that your oil level rises about a quart in 2000 miles, but that's easy enough to fix with more frequent oil changes.

-=Russ=-

 

Doesn't this "use up" your crankcase oil over time? Is this injected oil, however much of it actually burns, spit out the exhaust system?

 

1 qt per 1000 miles of flogging your car....it all burns...the exhaust is stupid hot.

James

 

1 sq per 1k miles, if your in good running condition.. on a older rotary and being hot dogged alot expect as low as 300-500 miles per quart. mine used that much, and the oil control bearings wear fine...

 

Yes, it uses crankcase oil. Which is why if you never check your oil, you'll run out of oil and destroy the engine.

Premixing, I usually gain about a quart every 2000 miles, which is consistant with what other people with similar engines who premix see.

-=Russ=-

 

So would you recommend disabling the factory OMP and going with premix, even if your factory oiling system is working? And do you change your oil at 2K?

 

no. just premix along with it. should be fine.

 

Eh.

I recommend disabling the MOP, because even if you premix on top of it, you still have crankcase oil getting injected and burned, which it's not designed for.

However, if anyone else EVER drives your car or fills it with gas, I wouldn't suggest it. I have no problems remembering to add 2-cycle oil, but I'm also the only person who ever fills my car with gas (and, with a few scattered exceptions, the only one who drives it). Running a tank of weak premix (or no premix) won't kill the engine, but it's not good for it either.

-=Russ=-