At first I wasn't thinking about doing this...but now it sounds like a damn good idea. I have an 88 10th ann with 45,000 miles...so it's been injecting the oil for awhile now. But, the car has had an easy life with 18k miles being put on it in the first 10 years of it's like and the rest were put on since then. I don't know how dirty my rotors are but if I switch to the pre-mix it'd be nice to clean out the deposits. What do you guys suggest? Also, is it true that the car doesn't start injecting oil till certain mileage or is it all throttle based? I remember my dad saying that he didn't really have to add much oil..then when I got it I had the oil buzzer go off when I pulled up our hill and was like...hmmm must be using the oil now.

 

Generally:

Keep OMP - little to no performance mods

Premix - LOTS of mods & high performance output

The OMP is monitored by your ECU and will light up the "check engine" light should it fail.

A tablespoon of ATF in the sparkplug hole, occasionally, revving it to the readline once in a while, and a bottle of techron concentrate (fuel injectors) is all good preventative maintenance.

 

Ok i'm bored so here goes....


I just switched to premix last week. Runs a TAD bit smoother now. Here are the benefits to PREMIX.

OIL DABBLE : The stock OMP just pumps oil into the chambers. However, the oil just dabbles down and pools on the apex seals. Take apart any old housing and you'll see an "oil line" coming from the injectors. You will also notice uneven wear on the apex seals. When oil is sprayed into the chamber with atomized fuel, it covers the rotor face and housing MUCH better than small streams of oil. Engines running premix that have been taken apart don't seem to have this problem and the wear is less, and even

CARBON BUILD UP: 4-Cycle oil from the pan burns alot dirtier than 2-cylce oil. It leads to lots of carbon build up --cabon that will cake to your seals. When that carbon breaks loose at high RPMs, well let's just say that the apex's won't be too happy (BOOM!). IT also fowls spark plugs and O2 sensor and what not. 2-cycle (WT-C3 certified) oil is made to lubricate just as well AND to burn off extremly efficiently for fuel injected engines. RETed said that he takes his engine apart every 20k or so miles and premix run engines look MUCH cleaner and healthier than OMP ones.

RELIABILITY: If your OMP line snapped some day, would you know it? I'm sure 11+ yr old injectors are allowing oil to flow BOTH ways, thus not allotting the correct amount of oil the OMP should be puttin out. What if the oil line gets clogged?? I've heard too many stories of engines going out due to OMP or related components failing ! This way, you have peace of mind that your engine is being lubed properly and will last.

In all honesty, premix DOES work better than the stock OMP injection. The only reason MAZDA put it there is b/c the average "Joe Shmoe" isn't gonna wanna run premix every time he fills up In fact, in some GTU races, they ran premix into the engine for obvious reasons.

You should follow this formula:

1 oz/gallon without the OMP.

1/2oz per gallon in conjunction with OMP.

Make sure the oil you buy is WT-C3 (or is it WC-T3, something like that) certified. This means that it is made to run in fuel injected engines and won't clog anything up. It also burns MUCH cleaner.

I use Valvoline Multi-Purp. 2-stroke (blue bottle)

Hopefully this clears up everything about the OMP vs. Premix. This thread should probably be archived.

There, hope you understood my LONG *** POST !

2-cycle oil costs about $20-$30 per year. . Much better than paying $2000+ for a new engine .

 

Dre 2K--very nice!..now im gonna run to home depot and buy the bolts i need to plug where the oil injectors use to be and email K2RD for the OMP block off plate..

 

I recall Mazdaspeed7 saids it does. So add another $30/year on top of the premix.

I'm ready to try premix, but not sure how it affects the spray pattern, if at all.

 

Well, looks like I will be running premix when I get my ride runnin again!! Good info guys!!

 

Thanks!

I got most of my info from this thread. . Lots of info. and pics about doing the conversion. Incl. comments from RETed.


There is also tons of info here too! Read hypntyz7's post for some expirienced info.


Just goes to show what a little 'search engine action' can do ya .

Hopefully someone will archive this thread so the question doesn't come up once a month.

 

Yes, I just did this to my personal 87 t2 this weekend. What was said about the rotor housings being unevenly grooved is very true. I have a whole shelf full of housings with a shiny ring around the center and a dull worn surface the other 95% of the width. Only about 2mm in the very center of the housings gets lubed.

With premix, its being atomized with the fuel. IT gets sprayed in evenly, and coats all surfaces evenly.

For those of you who think it makes the fuel thicker, or will gum up injectors or filters, I want you to do a little experiment. If you have a week-eater it will be twice as useful.

Get a gallon of fuel and mix 1oz of 2 cycle with it. This needs to be in an open container such as oil drain pan, tuperware container, etc. so you can see the results. Now stir it up, and look at it. Does it look any thicker to you? Get some on your finger...does it feel any thicker to you? Effects of this are minimal. You're adding very little oil here. IT might be a good idea to change your filter yearly rather than every 3 years, but what the hell.

This mod also gets rid of all those damn leaky as brittle vacuum hoses, and makes alot of room too. IF you take off the OMP and make a blockoff plate like I did it cleans it up even more. Hell, I took off EVERYTHING from my car...all emissions, vacuum hoses, rail, OMP system, everything. I ttakes me all of 5 minutes to pull my upper intake on my turbo II now.

Just keep a quart of 2 cycle in your storage bins for those times you're in BFE where the store doesnt sell 2 cycle. I ran it for 2 years on my old 89 GTU and it ran mint the whole time. Those s5 cars have a bad tendency to die from this electric OMP ****, but even the early OMP systems were not great for the reasons discussed above.

 

To reply to vaughnc statement: My car is an 88 and thus has the mechanical omp and unless there is a little miget that runs from where the omp used to be to the computer, I doubt the computer will find out and set the check engine light.

 

No, there is nothing like that. IT is purely mechaical. There is no electronic monitoring system on 88 and back.

 

I am curious as to how the gas and the oil mix. When my car sits all night; won't the oil rise to the top of the tank and rest above the gas? I know oil and water do not mix well and will seaparate after a few hours. Wouldn't this be fairly harmful on start-up? I guess after you start driving that the motion of the car would stir the liquids, but how about the first five minutes when the car is at idle and you letting it warm up? I believe that running the stock OMP "AND" running a lower dosage of premix would be the most reliable solution. If your OPM is real old or broken then ditch it. But if it is in like new condition or has very limited milage, I say keep it and add a lil premix to be safe. Many "NA" rotaries have gotten to 150,000+ miles running the stock OMP, which makes me think, it must do it's job preaty well.

Mazda could have also raised the stock boost on the turbo 2; but avarage Joe Shmoe wouldn't like rebuilding engines every 40,000 miles!

 

I already see more threads springing up about this same topic...

 

Dude.. Gas is made from ...OIL!!! So guess what... They mix very nicely.

 

Yeah if gas could be made from water, I'd be a very happy man. Maybe this is something the rotary gods can do

 

Yo,

This is from Felix Rotary FAQ:

Should I mix oil in the fuel?

Most small 2-stroke engines are lubricated this way, chainsaws and leaf blowers, for instance. So were 2-stroke motorcycles and outboard engines. Then, someone figured out that injecting oil into the intake stream could be more efficient and convenient.
When there is little load, little oil is needed. When load is high, more is needed. Mixing oil with the gas serves this function in a broad sense, as more fuel, and thus more oil, is consumed under higher load. However, there really is much less oil needed under typical conditions, whereas quite a bit is necessary at the highest loads. And, at idle, an engine runs much richer than under most other light duty conditions, but it consumes much more oil than necessary if it is mixed with the fuel. Oil injection simply offers a better match between oil required and oil supplied.

Race cars have different requirements than our street cars: 1- Idle time is low; 2- Idle quality doesn't matter; 3- Reliability matters a lot; 4- Combustion chamber deposits matter little, as race engines get rebuilt frequently; & 5- The engine is operated at or near peak load most of the time. Mixing oil in the fuel provides an adequate match between oil needed and oil supplied under such conditions. And, one more potential system failure can be avoided, besides a little weight saved.

Another thing to consider on this subject is that less oil than needed can cause excess wear, or even a blown engine. More oil than necessary can cause a blown engine too. Huh? If yours is a turbo, you want the most octane you can get. Oil acts as an octane reducer, so too much can bring on detonation you might not get otherwise.

Those who still want to mix oil in the fuel instead should know that any oil you buy for premixing with your rotary's fuel that is claimed to be a "special" formula probably isn't that special. The same properties that make a highly desireable small 2-stroke oil also make a highly desirable rotary oil: easily mixed and stays mixed with the fuel; burns cleanly, leaving behind few deposits to build up in the combustion chambers or foul spark plugs; and minimal octane reducton.

The most highly stressed racing rotaries run without oil injection have oil mixed in the fuel at a 100:1 ratio. Ratios up to 160:1 are acceptable for less severe racing service. Full oil-rich from the stock injection pump is roughly 150:1.


So what do you guys know about the octane reducing thing? I'm not opposed to running premix, just why is there a caveat?

KS
1989 GTUs "I love that FAQ."

http://mrmazda.members.atlantic.net/...html#OPERATION

 

I see two downfalls.

- reduction in octane rating as RarestRx mentioned. Probably not an issue for NA's but certainly a concern for turbos.
- when you decelerate, the ECU cuts fuel to both rotors. If your just doing premix then its no fuel, no oil during decel.

Personally, I would rather go the separate tank for the OMP route. Run TC-W3 oil for the OMP and synthetic in the sump.

I've got 146k on my engine with mechanical OMP so its gotta work pretty well.

Henrik
87TII

 

It can't possibly cut ALL the fuel to each rotor. IF so, then all those engines that have been running premix for xx,000+ miles should be dead....

 

so how do you know if your omp is working. Well obviosly the engine isnt blown, but how would I know if it did decide to stop working

 

ANd when you decelerate on a stock engine, the OMP stays open and continues injecting oil...riiiight. Check it out sometime...close the throttle and watch the rod close as well.

 

hypntyz7 is right, the throttle opening and OMP opening are connected directly. On an S4, as the throttle opens, the linkage going to the OMP moves up, allowing it to open more and when the throttle closes, the linkage goes down and closes the OMP.

 

So your saying that there is no oil injection when the engine is idling on the stock setup? The linkage is just as down in this position as it is during decel. The linkage certainly controls the flow rate but somehow I don't think it goes to zero at idle. Has anybody taken one apart?

Henrik
87TII

 

It sure does. This is a common fuel saving technique used in every EFI system I’ve ever seen. At zero throttle and over 1500rpm the injectors are shut off, as no fuel is required.

 

Its not a big deal to check into. Just get a 10mm box wrench and take one of the banjo bolts out of the oil metering pump. Start the engine. Look at the hole in the oil metering pump. Look for a black substance that is oily. I agree with some things on this thread and other things......well no.