TheOnesAndTwos

Now before everyone jumps on me here...I have researched numerous threads relating to premixing (including that on the FAQ thread). I'm not asking ratios that I'm pretty confident about (16oz to a full tank). The answer I'm looking for relates to how do you know if it is enough. Should the exhaust be bluish?. Here's the senerio. I added a 16oz bottle to my tank and filled it up (not all the way about 3/4 of a tank). This is my first time premixing so I'm not sure. I figured the exhuast would be bluish (and it was for a short time after starting the car up but that stopped). So is there enough premix in there?

Any input would be great. Thanks.

Brendan

Hades12

More then enough. 1oz to 1 gallon is the norm.

You will know it is more then enough when it stinks.

aspirao

I use AMSOIL 2 cycle racing oil 4 ounces to every five gallons on a 12 A pp

robs_seven

iTrader: (1)

Idemitsu rotary premix 1/2 ounce per gallon great stuff does not stink and its clear not oil brown. highly reccomended

capt murph

That gives a 1:160 ratio That might be OK if you are still using the oil injection and just adding some.

Mazda Competition prep manual suggests using a 100: 1 ratio for a straight pre-mix arrangement.

That would mean 5 ounces to every four gallons of fuel.

capt murph

I met a fellow that drag races a 7. He thinks the 100:1 ratio is not adequate lubrication for his situation, a dedicated drag car, turbocharged. He uses a ratio of about 80:1. So I guess when it comes to premix, you need to consider the application.

As always, one size does not fit all.

Wankelguy

Different oils will require different ratios.

Generally, synthetics will require a lower ratio.

You can't really overdo it, unless you get it so rich that you start fouling plugs.

twister7

iTrader: (3)

Mazda Competition prep manual suggests using a 100: 1 to 150:1 ratio (witch was in 1980 sorta out dated)and racing beat says 3 1/2 to 5 gals n/a and up to 22oz of oil to 5 gals of gas in a 600hp 2 rotor turbo and the rx8 is said to use less than 1/2 the oil of the 13b,,,to much of a difference between them all,,make's me wonder if this is sorta a trial and error thing,,***any one know what the ratio is in a stock set up omp**or at the wide open Setting** ,u know the one that make ur motor go 150k plus,,or has any one have any real mileage on premix and what ratio did they use (iam talking 100k plus,,tear down and inspect or at least 50k,lol don’t think this will happen))looking at the stock omp,,it looks like it change the amount depending on rpm and throttle,, harder u push it the more oil it gets also the one way valve (injector) iam sure gets some through the assist of vacuum(suck some in),,,not that iam bashing premix or any thing,i can see were it could be more reliable as u would eliminate possible failures(omp,lines clogging,line breakage) and those dam little plastic line scare the hell out of me (fist motor blew because of those dam things)and the last few day's i have tore down 5 motors and can see were a wider spread of oil(not just in the center & primary ports)of oil would come in handie or aleast 2 more injectors on the outer ports(think the rx8 has that setup better) and yes there was carbon freeking every were so the 2 cycles oil would cut it down some iam sure,,but then again what motor have u ever taken apart and not sean any carbon build up,,there is always some but they is alot less when the motor is proplerly cared for in the first place with regular oil changes,air filter replacement exctra anywyas enough typing and again does any one know
,,***any one know what the ratio is in a stock set up omp at the wide open Setting**???

R_PROWESS

iTrader: (3)

ya i use 100:1 straight

FIBREMAZ

50:1 100:1 and 200:1 are the most commonly used ratios. I'm with keith^^^ I run 100:1 generally racing 2 stroke or even marine outboard 2 stroke if there's nothing else available.
13B PP running mineral oil 20W50

MosesX605

I've read somewhere (though I can't remember where) that the stock OMP on 1st gens pumps out at 150:1 at full capacity. I therefore premix my gas at that ratio, so that it has the full lubrication that is needed at anytime.

Stevan

iTrader: (17)

It is written in How To Modify Your Mazda Rx7, I thought it was in the older RB catalogs also.
Thats the ratio I use too.

Hyper4mance2k

iTrader: (40)

You should not see it burn. I used to put a whole quart in per fill up and it didn't burn noticeably.. You should not see it burning. Remember that 2 stroke will drop the octane of the gas, so if you're NA it helps, but if you're turbo YOU CAN OVER DO IT. Too much oil will increase the likelyhood of detonation.

struhall

if it helps, i figure out how much 12.5 gallons of gas will cost, and round to the next dollar, and add 16oz of premix. last night, i did the math, and i was sitting at about 102:1. but as long as im close to 100:1, im happy.

the only time my car smokes is when i havent gotten on it all day, and i step on the gas. but once i do that, it quits smoking. this is on a streetport 13b with a holley 600 (running rich)

John64

I use 8oz of MMO at every fill up.

steve84GS TII

Most definately you can overdo it.

I premixed for a short while when my S5 front cover was being made up.I also had a S4 OMP in place,pumping in the idle volume of oil in addition to the premix in the tank......I couldnt make sh*t for power! At first I thought my newly installed S5 TII setup was bunk,or I had set the timing wrong or something.It just had no power at all.The instant I installed my S5 electronic OMP and filled the tank with straight fuel,my power was back in full force...just like that.

As a side note.....in addition to 2 cycle oil reducing octane,there is also the potential for altering the fuel/air mixture.Remember that 2 cycle oil is neither fuel nor air,but it takes up a measurable amount of space....space which would normally be occupied by fuel.Thus,too much oil in the fuel can lead to a lean mixture condition,which is very bad in a turbo application.This is ironic since when people put too much oil in a premix fuel,they tend to reffer to it as "rich mix",when in actuality its leaner in regards to the actual air/fuel mix.

For the record,I have no idea if this actually can affect rotaries within reasonable mix ratios.I work on a lot of small 2 cycle equipment in my trade,and when it comes to super sensitive,small machines like chainsaws,weedeaters and rammers,oil mixture ratios can be a big factor.Especially on newer equipment which no longer have fuel mixture adjustment screws on the carbs......

Rogue_Wulff

Personally, I have the stock metering pump hooked up, and supplement that with ~1/2oz per gallon. I mixed a little heavier for a short time, when I had a oil line leaking. I am willing to chance needing to clean/replace plugs a little more often, in exchange for *hopefully* extending the life of the engine. I don't have a cat, therefore I am not concerned about extra oil causing the cat to clog up.
That's just my way of doing things.

twister7

iTrader: (3)

download and read www.mikesdriveway.com/misc/rx-7.rar Kenichi Yamamoto's "Rotary Engine" page 73 there are also misc ase paper in the rar file!!any ways it is sorta against premixing from what i can tell "",,stock ratio is between 150:1 and 250:1 depending on the driving conditions!! also check out what royalpurple has to say about synthetic oil and the rotary,,there is also a bit about the omp on there also " The stock metering oil pump is a great system as it varies with throttle position (load on the engine). Pre-mixing has to be calculated for the ‘worst case’ that will be seen by the engine for that fuel load. Under racing conditions, that’s wide open throttle at racing rpms. This means that at idle, the ratio may be slightly fat (rich)."
http://www.royalpurple.com/techa/faqsa.html#re0
from what i can tell premixing has the opsite effect of what every is trying to do (reduce carbon build up) cause to be safe when premixing u have to add more than is needed ,, more oil more build up=premix ,,omp=oil that is needed less build up!!i say the key is maintance regular oil changes exctra maybe even water injection to keep things clean,,those ase paper's rock any one have any more they can post link to?

RotaryRevn

Someone on the forum who builds motors once posted pics of the inside of a motor that has been premixed, and one that used the omp (both with the same milage) and the premixed motor was clean! Basically no carbon buildup. The omp motor had lots of black gunk in there. I'm still trying to find the best answer myself on this subject but I would think that a premixed motor is still metered because when you are idling, there is less fuel, hence less premix. Full throttle you have more fuel, more premix. Any thoughts? I know there is lots of good info in the second gen forum on this.

Rogue_Wulff

I'm on the fence, to a certain degree. My car still has the OMP hooked up, yet I still add 1/2oz 2 stroke oil per gallon of gas. I know 2 stroke oil is cleaner burning vs 4 stroke. I also understand the need to adjust oil for driving conditions. I just don't trust the aftermarket OMP adapters for using 2 stroke oil.
I can say this much. When one of my OMP lines developed a large hole in the rubber nipple, I was DAMN glad I had 2 stroke in the tank. I don't know how long it had been leaking, prior to my discovery of the leak, due to the puddle of oil. I know that all of the oil in the puddle, along with what dripped off, were supposed to have gone IN the engine, rather than ON it.

MosesX605

You're right insofar as the fuel is delievered with the fuel and more fuel = more engine speed. I think that the difference in carbon deposits in the premixed vs non-premixed engine would be that the engine wasn't burning as much 4 stroke oil, which doesn't burn near as well as the 2 stroke stuff.

Thats just my uninformed .02.

FWIW: When I rebuild my 12a core this winter and install it in my Solo II car, I'll be going 100 premix and disabling the OMP entirely. I just feel better about the oil getting properly mixed in the chamber rather than just dripping down the carbuerator venturies.