Premix!!! Read this please!
 

I know people are going to hound me for opening a thread about Premix because there are plenty in the archive, but everything I read about premixing seems to be wrong. I'm talking about the ratio and the mixture; specifically in the case of my S4 N/A which will have no OMP when I'm done with my rebuild. I want to run a fairly rich mix of two stroke oil in my gas, mostly because I'm very hard on the car (hence the rebuild, lol).

Firstly, I think a proper mix for me would be around 100:1... But I'm not exactly sure if that is the proper ratio to run. Second, what is with everyone saying "100:1 is 1 ounce per gallon”? This makes no sense considering there are 128 ounces in a gallon, not 100. So in that case I should be running 1.28 ounces per gallon instead of 1 ounce per gallon. This brings me to the next problem: all the threads on here I have read say "Just throw in a 16 ounce bottle of 2 stroke oil and you should be fine." Well that would be just dandy if there were 100 ounces in a gallon, and if my car had a 16 gallon tank :icon_no2:. But this is simply not the case. The tank has a 16.6 gallon capacity. So I did a little math and came up with 21.248 ounces. Holy crap! That’s completely different from 16 ounces! So, am I right? Should I throw in 21 ounces of 2 stroke oil in my tank? Or am I just crazy? :dunno:

PS: WTF is TCW3 and is it better or worse than regular 2 stroke oil?

Although I don't premix, from what I gather, the ratio for a street car would be in the 100/150:1 version, race engines 50/75:1, so the 1 oz to a gallon would be in the middle. TC-W3 is a certification for 2 stroke oil that meets certain crteria, so only use oil that is TC-W3 certified.

I think you're making a few dubious assumptions.

No matter the stated fuel tank capacity, you'll never actually get that much in.
You should base your figures on the amount of fuel you really carry, not on what the manual says you can.

Second, you don't add more oil based on how hard you think you run the engine.
Beyond a certain point, more oil in the gas is actually hurting you...you get more unburned deposits which leads to reduced combustion efficiency and even preignition.

Turbonut...it's a complete mistake to base anything on "what racers do".
Race engines are torn down constantly and the effects of such things as premix ratio can be evaluated and adjusted on an almost daily basis.
When I was GP racing we wanted as little oil in the gas as possible...oil doesn't explode as well as gas and more oil meant less power. We were willing to accept the consequences of cutting it too fine- trashed cylinders, pistons, etc.- in the quest for more horsepower.

One of the racing world's giants- Ferdinand Porsche, Enzo Ferrari, I can't remember- said (I paraphrase), "The perfect race car is the fastest thing on the track and then explodes after crossing the finish line".

A real world example of this philosophy is the early Ducati World Superbike team.
They didn't have the horsepower of the Japanese four cylinders but they did have a rules regulated weight advantage.
They exploited this by recasting their engine casings out of magnesium which saved a few precious ounces but the new cases only has a service life of a few hundred miles before warping and blowing the cylinders off.
This was fine for them though...if it lasted for the weekend, the part had done it's job exactly as planned and would be replaced. Usually- but not always- it did.

So, you can see that following the practice of "racers" can be a very expensive and dangerous path to follow.

i put about 8 to 10 ounces per tank in my car per fillup. anything more, and it spits blue smoke.

I think some guys take this a bit far, Ive seen guys fill up a 1 gallon can, mix, shake, then dump it in becuse they are worried it will not mix right in the tank.

On the omp an abused 7 will use up to 1-1/2 qt of oil per 2 tanks of gas ~500miles. At least thats what Ive seen. Its its also about what the manual says.

Now consider the above when your doing premix. 1 oz per gallon is pretty heavy on the oil side and right where it gets a bit overkill. To make things easy in my head I pour in about 8 oz then fill up er up. Thats generally at 1/8th tank for me. Its less than 1oz/gal and way more than what the factory gave it.

I've done 1/2 oz to a tank on my last motor, when it was taken apart the rotors and housings were still in great condition, besides the chipped apex seal scoring one of the housings.

That is sig material right there!!!!!!!!!!!!!!!!!!!!!

Just trying to help out, but as I see it, these people certainly know more than most of us, so you can refute their stated ratios.
http://fc3spro.com/TECH/FAQ/premix.html

well, I run 1/2 quart of 2 stroke per every 3/4 of a tank (roughly 12.5 gallons), and the engine I took apart from a blown coolant seal was absolutely mint: no scoring on the rotor housings, no real carbon buildup on the rotor faces, and after 40,000 miles on that engine, I had to get the ten thousandths micrometer out to measure apex seal wear, which was only .0002 less than what they measured new.

Therefore, I feel that this is an absolutely acceptable ratio of premix.

^^Hey thanks for posting that article. It really had a lot of good information in it. I just started using pre-mix and I will never go back to that mechanical OMP.

I used an ounce of tcw-3 per gallon and I'll be cracking it open today so I can post pics later if you like. I'm pretty sure the internals are gonna be pretty good.

This has been covered before. Run too much pre-mix and you lower your octane which is dangerous to do especially on turbo charged cars. The 100:1 ratio is for two-cycle engines. Rotaries are Otto cycle (or four-stroke) engines. They do not need pre-mix in the way that two-stroke engines need it. The premix is intended to do the same thing as the film left by the piston-ring in a piston engine.

So what ratio do you suppose a turbocharged rotary should use?

I used Idemitsu premix and they said half ounce to a gallon which is 256:1 ratio.
I run between half to a full ounce to a gallon since I dont really care for exact measurement on premixing. As long as its not overly too much to cause a smoke screen or too little, which wont happen since I make sure its a half or more.

your best bet is just to run 256:1 ratio which I run on both my n/a and turbo.

I have an S5 NA car, and run 1 oz to 1 gallon of gas. I run any premix, as long as it's TCW-3. I pour my premix in before the gas goes in, so I'll pour in like 13 oz of premix, then do 13 gallons of gas. Seems to work fine for me.

Now that that :rolleyes:is settled, your next question will be:

"Why does my crankcase oil level rise when I premix, and how often should I change my oil?????!!!!":lol:

a quote from the link

"A proper removal of the internal OMP gear would require removal of the front oil cover, but this is too involved for most people. I've heard a pair of U.S. dimes can be inserted into the hole to keep the OMP gear from sliding around inside the front cover before covering everything up with a block-off plate; if this didn't make any sense to you now, it'll be obvious when you take everything apart."

what does this mean exactly? is not removing the omp gear going to hurt anything? i was literally just about to go outside and finally remove the omp system and run premix when i ran across this.

Hmm, I am using that 100:1 ratio thingy, but in metrix. 100L of gas : 1L of 2strokes oil.

So, if u fill up 45L (11.9 galons), I put in 450ml oil (not sure how many ounces).

I use Premix. for both my FC and FE

1/2 oz per gallon.

couldn't be happier.

Well that's all very nice... Everybody does it completely different! LOL :sigh:

I'm just gonna run 1.3 ounces per gallon and call it good.

stock s4 n/a
intact and working omp
new oil injectors and lines (last winter
4oz. per tank

I just like to be on the safe side in case my omp were to fail

rotaries are technically 3 stroke but many are labeled otto cycle when you go to a dyno facility.

That's an interesting take.

My mechanic recommended 1oz to 1gal ratio of

http://www.mazdatrix.com/pictures/Premix.gif

in my TII Vert swap. I'm inclined to follow his recommendations. OMP removed.

FYI, I e-mail Mazdatrix about the Idemitsu premix. They replied, if you have a working OMP, 1/2 oz per gal is fine. If you have no OMP, you should increase your oil to 1 oz per gallon.

I had this questions before regarding 100:1 or 128:1.

The answer that I discovered? Use 1 oz per gallon, you'll be fine.

If you do have a working OMP, 3 - 5 oz per tank is the generally accepted ratio.

Well I'm not going to run a Oil Metering Pump. I've got my answer. Thanks Guys. :)

1/4 quart per tank. my s5 jspec has at least 100K on it by now and is doing fine.

8 oz per tank? With or without OMP? With OMP, that's too much.

Without OMP, you could run into situations where you don't have enough lube, but those situations are few and far in between.

ive leaned out to 1/2 oz per gallon and feels like its gained a little power. If you do the calculation from the stock oil consumption with hard driving (1qt every 1000miles) it comes out to less than 1/2 oz per gal

these are very good questions. I have wondered about this ever since I started premix.

Do you or anyone else have the answer for these questions?

blowby?

This is the same equation I'm thinking of using on my 1990 vert N/A still have the omp. However which brands would you recommend? And how abusive are you with your engine?

Since I started this thread, I have been running Walmart "Super Tech" TCW-3 because it was the cheapest gallon of 2-stroke oil I could find. That's more than 7 years with no issues. I don't think you need to run 100:1 ratio if you're keeping the OMP, and especially if you run a catalytic converter as it will quickly become ruined. I'd start at 200:1 and go up or down from there if you need to.

I use Lucas Semi-Synthetic 2 stroke. 10 bucks a quart at oreillys.
https://cimg4.ibsrv.net/gimg/www.rx7...ae4ef48d2e.jpg

i'd rather spend $12 a gallon, like i have for years. money saved pays for a rebuild after all.

Meh, i dont drive my car much, maybe 200 miles a month at the most. So what the hey.

well, over the course of the last engine that went about 80k miles, it used roughly 4,706 ounces of 2 stroke oil. for me it just made more sense to not spend more than i had to since that is roughly 37 gallons of oil, which came out to be in the neighborhood of about $450.

at $10 a quart for the higher end oils it would come out to be about $1600 after tax.

small difference, i know. though i drive my car much less now i still use the cheaper stuff, because it works just fine.

I ran over to walart and found what you recommended, doing 1/2 oz per gal at the moment, engine seems to run no different which im guessing its good? and no cat, straight pipe w/ racing beat duals.

I hope you're not doing that with zero OMP, because that would put you in the region of 256:1.

"Seems to run no different" is exactly what would be happening if your c̶o̶r̶n̶e̶r̶̶ apex seals were carving out your housings.

wut?

err, apex seals.

I shouldn't be allowed to post late at night :lol:

Fixed.

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​​​​​​I still have the OMP tonight was the second night I ran it with premix at the same ratio I did notice the idling was smoother. I'm tempted to go 0.25 more to make it 0.75/gal what do you think?
​​​​​​​How would the apex seals carve the housings after mixing? Shouldn't it be opposite? And thanks for letting me know that BTW.

he was just exaggerating the truth, some people actually only run .5oz per gallon with no OMP and have no wear issues, i run 1oz with no OMP because it's just more peace of mind. .5oz with the OMP is probably best.

I kinda figured he was, :scratch:
im using the highest octane rating I can find which is tipically 91 since I read that premixing can bring your rating down, also love getting that weird look when I pull out the funnel and bottle to drop some in lol

you don't need high octane for an n/a, plus think of this, at 128:1 ratio your octane would only be lowered by a maximum of .8% X 87= .7 tenths of an octane point making it more or less 86.3 octane if running 1 oz per gallon, 86.7 at .5 oz/gal. not enough to worry about, and virtually what the cars dealt with while injecting the crankcase oil for lubrication.

thank you!