I got a TII on premix with a T04 and 1000/2000.
I have been using about 12 oz per tank,which is less than the "normal" 1oz to One Gallon of gas.
Now this is on Haltech.
I had it on the RTEK 2.1 and tuned and it fouled the trailings.Maybe over-premixed.
(got Trailing coil error)Hence going Haltech.
I just had enough of the stock wiring and crap associated with 20 year plus old stuff.
..
JJ..not mad...heh,heh..but I am a little "coo-coo for cocoa puffs" at times!

 

A stock fc ecu reading an sensors that are properly set (ie, 1k ohm tps at idle, etc) goes FULL LEAN on decel. So there's zero lube on decel from a premix engine aside from residual oil, and an omp engine is seeing idle condition oil injection as it reads the throttle position not engine speed (s4 ref.)

There may not be decel fuel cut if your conditions vary from this any (different, aftermarket ecu and not using decel fuel cut, or a stock computer w sensors not set to fsm specs.)

 

Every day is April 20.

 

If the lemans 787b ran with only premixfor 24 hours straight its a testament showing only premix and no omp is perfectly fine. Lots of rx7 owners pre mix without the omp and never have problems.

I don't smoke that stuff, quit a long time ago.

 

Running 1:1 Premix. No OMP. Motor Has 2000 miles on it. So it will be awhile before I
take it apart. But she runs great.

 

I can see how you'd form a hypothesis from this but really, two engine teardowns is hardly enough data to come to a conclusion.

 

I didn't post ratio's because that has been beaten to death already, and I didn't want this thread to decend into a debate.

Alas, not only did it decend into debate, first reply is loaded with misinformation.

 

Sorry man.

I admit there are some valid points that you've contributed, there is no right or wrong, and no matter where you go people will argue their point of view.

That said do what you're most comfortable with, we all know using only the omp and no pre mix at all is the worst option.

 

I didn't suggest just running the OMP by itself, this thread was intended to...

A)Explain exactly HOW premix lubricates and the science behind it and...

B)How awful it is to just run with the OMP without premix.

Those housings pictured are my own housings from when I rebuild a 160k mile engine that never saw premix. That engine was original when I took it apart, it even had asbestos gaskets in it!

Working OMP or not, premix your engine, it'll love you for it

As mistery stated, not all of the premix burns off, so you'll have some left during decel. I just personally prefer having the OMP still for that situation. The reason i know this is because I rebuilt a homelite leaf blower last month for my mom, and when i crank it up and tested it, a little oil would make it out of the exhaust port.

 

I know you didn't say to use it by itself , I was just stating that as general knowledge.

I never pre mixed my first rx7, now I've realized how much I was missing out on.

Before I was all paranoid thinking it'd clog my fuel pump, injectors, and fuel filter.

Now after seeing how many people do it with positive results I have no reason not to do it.

 

You know, intellectually I can buy into this proposition without qualm but then I'm left contemplating my (nearly) 250k bone stock engine that has somehow managed to survive 24 years on "the worst option".
Is my experience the outlier here?

 

I doubt your engine has never been rebuilt or replaced. I'm saying 99% chance it has been rebuilt/replaced.

That said, the stock omp works yes it does but there are better options.

 

The fuel/air charge in a 2 stroke engine lubricates the crank case as well as the cylinder and in most cases are mixed at around 40:1 (3.2 oz per gal) which is relatively high compared to what most will run in their rotary at about 100:1 (1 oz per gal).

FC3S Pro v2.0:&nbsp FAQ - Pre-mix

^ a good read.

Idemitsu Lube Spec sheet
http://www.ilacorp.com/images/web_premix.pdf

 

Idk why they fail to say use .5 oz/gallon if you have a working omp and 1oz/gallon without

 

Good stuff, thanks for the info. I run premix with no OMP and was always a little worried about the premix.

 

Yea ... but shows what omp and premix does to internals.
Not scientific , but enough .

 

You'll be fine, many of the hardcore rotary enthusiasts premix with no omp.

 

Just one thing I've read/heard but didn't see mentioned in here, fuel cuts on decel, but two cycle oil is designed to 1) burn off cleaner and easier that four cycle oil(less gunk) and 2) leaves behind a "dry residue coating" that lubes between/during cycles.

Being that rotaries are known for running rich I would assume more "dry residue" is left behind than needed, that leftover would lube your engine on decel. Again assuming your on the gas more than not(which you should be if your piloting an rx7 anyway ; ] ).

 

Stupid question, but I want to ask anyway. You can start using premix anytime right? Like there's nothing wrong with my 112,000km stock engine going from never using premix to using it suddenly. The wear that's already on the housings will always be there, but it'll help with wear from this point on, correct?

Do you guys measure how much you're putting in and how do you put it into the tank after you've measured? I still have my OMP and I'm Canadian so I'd estimate one oz/30ml every 4 liters of gas (a little over 1 gallon). This seems like a PITA since I always put in different amounts, I almost never fill up, 20$ here, 10$ here, etc. Would it still be worth it even if I plan on swapping the engine once I have the money(probably next summer)

 

That is why I carry the small bottles.(approx 3oz).
Each bottle does about 20 buck in gas.(Canadian)
If you want to stick with the ONE to ONE ration then use your noodle..Get the math book out Schroeder and convert it!...(chuckle..youngsters..lol!)
I'm stickin with my bottles per 1/4's..(that is about 12 oz per tank on an s4).
It beats having to look at a big bottle and go Pour..nope,not enough,glug..nope..GLUG..ah ****!

 

I don't think it can be too late to start premixing. It can only help unless you over mix or something.
I usually look at how much I have in the bottle and guess how much gas I'll need...pour in 10oz of idemitsu and then fill up about 10gal of gas that's good enough for me...

Be careful to use only premix oils of the twc3 type as they are the ones we would use. Or unless it says for rotary use (like idemitsu)

 

@ryan hey bro 100:1 without an omp so thatd be 100mm for every 10litres. I'm assuming the 2stroke 1litre bottles will be marked in 100mm increments up the side of the bottle like ours are so pour and check like mysterstyx says. I carry a funnel and rag in the back.So you just have to work out how much every 10litres of fuel costs and ask for gas in strange dollar amounts. It really weirds out the gas station attendants Can't remember the with omp ratio. 400:1

Sent from my GT-I9100 using RX7Club

 

Doing it without it pre measured is like mixing lets say vodka with orange juice, there's a 1/3 chance of getting the correct ratio.

Sometimes it'll come out strong and you'll have to add more orange juice, sometimes it'll come out weak and youll need to add more vodka, then sometimes it will come out perfect. When making drinks you can drink it to see if its right or not, obviously there's no way to test your gas after pre mixing and pumping in your gas (that I know of).

 

this is the factory metering pump test data, and the S4 vs S5 metering pump maps.

 

reading this thread is gonna make me add more Vodka..to anything..