premix ratio without OMP
 

I know this has been discussed many times. I just wanted to ask what is the MAZDA's mix ratio or our concensus for 2 cycle oil mix ratio? I deleted my OMP.

I always read 0.5oz/gallon to 1 oz/gallon, but these seem to be with the OMP. What's the premix ratio without the OMP?

thanks!

premix ratio without OMP
 

1oz/gal is typically WITHOUT OMP. 0.5oz is typically in conjunction WITH OMP. Some choose to mix more, but these are typical ratios.

excellent. thanks!

Ideal is no less than 1:1. But you want to run as much as you can before it starts to smoke out real bad.
If you going on a long road trip its a good idea to mix heavy to help resurface the surfaces and mix heavy if your racing.

thanks all. I guess mix heavy whenever possible? :)

just out of curiosity, wouldn't that change AFR because the oil is more viscous and burns at a different rate as more of it comprise the fuel mixture?

in other words, when I tune my car at 1:1 mix ratio, would running 2:1 lean out AFR in otherwise same condition?

I wonder the same. How does it burn and what does it do to AFR and compression possibly

anyone care to chime in?

I have never heard anything like that.

Well it must cause compression because it is used to start engines that are flooded or dont have enough compression to start otherwise. Right?

Incorrect. Your using straight oil to help with comprrssion when your doing that. A engine wont run with too much oil. The point of putting oil in rotarys to help with a compression issue is to create a hydro lock type of state even though you cant hydro lock a rotary.

so it must not foul spark plugs as easy as gas or flood the engine?

youre saying it has no effect whatsoever on a/f ratio or compression when premixing even a heavy dose?

If the ignition system is running properly why would it foul your plugs any more than the OMP? Also, of course it'll have some effect on AFR, just like summer vs. winter gas does, you're effectively altering your fuel blend. Unless you manage to do something horribly wrong it'll be negligible.

AFR change will be so small you wouldn't notice it.

What will change is octane. 2-cycle is definitely not as resistant to burn as gasoline. The heavier the ratio of 2-cycle, the lower your octane.

I do not know ratio vs flashpoint effect at ratio's we commonly run, but if you were theoretically to pour a few quarts into your tank, most likely detonation could be a real problem.

Just run 1oz-1.5oz per gallon and be done with it. No issues here, and only a little blue weedwacker smoke! I like it!

Thanks for clearing that up Monsterbox...we were using the wrong terms.
Need to be careful to premix the right amount and stay consistent with what was done at time of tune with how fragile these engines are to detonation.

1oz to 1gallon usually on street driven cars I know people that run 1.5oz to 2oz to 1gallon on high up drag car

I know people that run marine synthetic 2 Cyl oil and supposably you won't get as much carbon build up but I haven't seen evidence or a write up about it

Really I thought people were using a 4oz 2 stroke premix with each tank of gas.

i run TCW-3 marine oil in my car without OMP. i run 0.5 ounce per gallon. My car is NA and is never on the track. As many people before me have said, 0.5-2 ounces per gallon is typical. Not every engine is the same. you have to play with the mixtures until you find what works best for your car/mods/application. again, my car seems to like 0.5 and i have never had any issues therefore i will continue to run 0.5 until my car tells me otherwise ahahahahhaah good luck.

From Pettit's Website

Recommended usage is 1 oz. per gallon of fuel. *minimum of 6 oz. for 10 gallons

I don't know if this is with or without OMP.

And to the original poster, remember the OMP injected dynamically depending on how the car was driven. When you premix you're always getting that same mixture whether you're at idle or at 8k rpms and 20 pounds of boost.

My favorite setup is to keep the mazda OMP. Replace the lines with SS braided. Then give the OMP it's own reservoir of proper 2 stroke oil like pettit sells. this way the lines wont crack, you dont have to premix on your own and add too little or too much, you're using the right type of oil instead of dirty engine oil, and you can keep track of how much oil is being used and will realize there is a problem with the omp if your oil level isnt going down consistently. Thats my thought.

Regarding effect on octane, detonation and flash-point, I just looked up the flashpoint for a the most reputable brand of 98RON petrol that we get here in AUS - -40c. thats a flashpoint of negative 40 celcius.

The flash point for most 2t oils is about 80-90c. The one I'm using, Motul 800 has a flashpoint above 250c. The flashpoint for most engine oils seems to be around 220c.

I don't really know how to interpret that, but it seems to suggest that the 2t oil would help to suppress detonation if anything?

Also, was told by a reputable and well established tuner that heavier premix will lean out the AFR's, but i imagine the effect would be pretty negligable.


Edit, just looked up what "flash point" even is ; its the temperature at which a liquid's vapours will burn at the surface of that liquid. Basically the temperature that you can hold a match to something and have it catch. I have no education in this field or anything, but i have a gut feeling it pretty much has virtually no bearing on the way our fuel ignites inside our engines.

Flashpoint
 

Edit, just looked up what "flash point" even is ; its the temperature at which a liquid's vapours will burn at the surface of that liquid. Basically the temperature that you can hold a match to something and have it catch. I have no education in this field or anything, but i have a gut feeling it pretty much has virtually no bearing on the way our fuel ignites inside our engines.[/QUOTE]

Flashpoint is the Reactivity to Heat of the Catalyst Mixture.

In Layman's Terms; it's based on Temperature of the Mixture then introducing a Self or External Source of Ignition.

1.) Cold/Cool Diesel you can throw a Cigarette or a Match into and it will go out upon contact.
2.) Luke Warm Diesel has the potential to React to the Flame but unlikely to ignite.
3.) Very Warm Diesel will likely Ignite with the introduction of Flame.
4) Hot Diesel will Violently Ignite under Flame or Compression.


Be careful and do this outside:
"Burnish two Ragu Caps together with Soldering iron or Welder, put a small hole in the center of one cap, place Diesel in a cook pot and bring it up to just shy of boiling, pour a small amount of the heated mixture into the Small hole on the cap, leaving a small pocket of air, Take a 5-8 pound Sledgehammer and target the Hole as the impact point, crush the canister and watch the Sledgehammer go through the roof if you are indoors.

The introduction of instant Compression to an already volatile heated mixture creates a Flashpoint that will react very quickly to Flame or ignition.

A sledgehammer flying into the air sure does sound like a good time. :lol: