ok ive been thinking of going premix but with the s5 omp being electrical it throws the ecu into limp mode when removed. now in searching ive found that people just buy rtek and be done with it but my question is..without buying rtek what other ways are there around it? most stuff ive found is for s4's.

 

You can pull off the OMP, put on a blockoff plate, and leave the OMP plugged in. This way the ECU still sees it, but it isnt doing anything.

 

well, I just pulled the OMP and put a block off plate in place. I then strapped it to the side of the engine bay and left it pulgged in. I'm sure many others have done this as it's the only option aside from ECU changes.

 

wow...... should have thought of that lol.

 

Personally, I just changed the nozzles with real screws and took out mecanism of the OMP. So the cumputer thinks it's still working... but it's not !

 

No, there is another way to do it, which is what I'm considering.
There is a setup available that sandwiches between the OMP and the front cover- the pump is still driven but the stock oil feed is blocked off, replaced with a nipple fed from an external tank.
Run premix in the tank and you have the best of both worlds...a functional OMP that injects premix instead of engine oil.

I admit I haven't tried this yet but it seems like a pretty elegant solution.

 

You mean a functional OMP that injects 2-stroke oil instead of engine oil. If you inject the oil, then it's not premix.

 

Um yeah, that's what I meant.

 

I don't think that is a good idea personally. I mean if your injecting premix then your changing the ratio of fuel and oil which defeats the point of premixing.

 

Assuming it's working, why not just leave the stock system in place?

Your car has been fine for between 15 and 18 years without premix, and running it now is going to make no difference.

 

Wrong, the whole point of premixing is to eliminate the use of crankcase oil, which is exactly what this mod achieves. The ratio of fuel and oil is not changed. It's not even relevant.

This seems pretty obvious to me, but pointless premix conversions still seem common...

 

There appears to some valid anecdotal evidence of the benefits of premixing when used from the get go on a newly rebuilt engine, though.
If one accepts this, then the mod I posted would seem useful or at the very least, not demonstrably harmful, no?

Besides, I have to wonder if the final implementation of the OMP wasn't arrived at with end user failsafes as a major consideration.
Injecting engine oil meant that Joe Sixpack needn't do anything but check the dipstick and pour more Castrol in when necessary instead of monitoring a second tank which required a completely different type of lubricant...especially a type of oil not commonly found at the local Exxon station.
I wonder if Legal and Marketing had any input into this as it seems likely that Engineering would have loved the idea of using a more suitable oil for the OMP, convenience be damned.

 

Yes and no...

My car (86 na) is 21yrs old and well I got it with 70K on the clock (well just over) if the car only has 70K on the clock then I think using premix NOW could benifit the engine alot.. especially if u are the type of person who also seafoams the engine..

Now on my 89' it has over 150K and well I would agre there that right now premix on that car is mostlikley irrelevant but it cant hurt either way..

 

+1 on spool's comment. It cannot hurt.

 

Anecdotal would be a generous way to describe it...

I love the idea of modifying the OMP this way. I think it's a great idea. I think it'd be neat to see someone develop a more complete package (adaptor plate, oil line, oil reservoir with low-level warning, etc), but I can't see it happening unfortunately.

IMO it was a commercial reality as much as anything else. Any automotive engineer with half a brain would understand that a car with specific and unusual maintenance requirements would simply not sell as well in the long run.

 

Nor can I but the execution would not be terribly difficult.

The adaptor plate already exists.
The oil line is not pressurized so almost anything would work.

I've been looking at the oil tank from a Yamaha RZ series as the reservoir.
It's plastic and it already comes with a simply wired level sensor (just a light when the level drops to a certain point).
Fairly large capacity, although I haven't begun to do the math pertaining to normal consumption so no idea yet about filling intervals.
If the shape of the tank become problematical there are lots of two stroke bikes to look at for donors- perhaps another one would be better.

Obviously, I am only in the initial stages of planning and much depends on other mods happening first but so far, it really seems pretty straightforward.

 

There's a number of people out there using a seperate reservoir for the omp. One that comes to mind is TitaniumTT. If you look at the other site you'll find a thread where he describes how he made a reservoir for the two stroke oil with a waring light etc.

Rotary Aviation makes the adapter that goes b/t the cover and the omp to act as the pump. Others use the original omp but it takes just a small bit of fabrication.

You really need to think just WHERE this reservoir is going to be installed. Look around a turboII engine bay. Ain't much room there, plus, and this is just a personal observation, if the tank is located above the oil injectors, the oil will siphon into the rotors over night. Not all the oil, but enough to make the car smoke in the moring for a moment. Not desireable in my vey humble opinion. The reservoir needs to be located below the oil injectors. Others disagree.

 

I have a NA and even stock there is room to work with but before I begin, the PS and AC will be gone as well as the battery, so room is not an issue.

I'm not sure about your siphoning theory but positioning the reservoir might take some work- not too high yet not too low.
We'll see.

 

There is NO check valve in the omp or the oil injector (not counting the rubber one in the injector for air). So if the liquid is higher than the inlet hole at the injector, there's nothing to stop the flow into the rotor chamber.

I HAD a reservoir made out of a propane torch bottle and had it where the old charcoal reservoir was. Nipple was at the bottom gong to the omp. Drilled and tapped a hole in the top for filling and had a dip stick made out of a old welding rod.

That arrangement fell out of favor this week. I think it had 32oz in volume, but I got the smoke in the morning. IF I moved the supply to a lower point there was no smoke for weeks. Reinstall the tank back where it was and the next morning....smoke in the morning. Plus I observeved the oil level at the end of the day vs the morning. Lower.

Gravity. My enemy.

There's other ways to mix without using bottles each fillup. Like a gallon tank in the spare tire area with a windshield washer pump at the bottom and the feed line into the vent line on the gas fill tube.

 

^^ That's a clever idea.

I haven't tested what Hailers mentioned about the 2-stroke getting pushed into the combustion chamber but I have a cure, first though I spoke directly with Richard Sohn (who produces said adapters after conversing with Hailers about this very problem). He told me that he had recieved a few complaints just like that. He tested a few OMPs and held the resevior 36" above the nozzles and he couldn't get any to leak after sitting for days on end. This leads me to believe that it is going to be car specific. Some will have the problem, others won't.

Regardless, the way to combat it is to build your own injection lines from parts easily obtained from GoodRidge or any other source and take a lesson from one of my teachers - the Marine Industry. We like to loop lines that exit around sea-level for exhausts and bilge pumps and live well tanks WELL above sea-level so a siphon can't start. In other words, if the line goes above the level in the tank, the siphon can't start.

I bought a tank originally designed as a power-steering resevoir, welded some tabs on and ran with it. I'm changing my mind about it and plan to sump it, add a baffle, and adjust the low level sender that I found @ an aviation supply. Wiring it in with the low sump oil light and sending that signal to the Motec which will limit RPM's and shout off the alarms.

For the amount of oil that it should hold..... well.... the going rec. seems to be run it @ 128:1 which means 1/2 qt per tank of gas. OK, the OMP injects sump oil at about a qt/500-3000 miles. That equates to anywhere from ~250:1 - 600:1 meaning you need between 3.5 & 8 oz. I'm a belt and suspenders guy so I went with the 16oz, I also decided that I don't want the thing to fall below half empty, so I doubled it. I have a qt tank and it's actually getting a weee bit bigger with the sump but whatever. Daddy doesn't want any airbubbles in his -6 feed. I actually figured out that there is enough volume in the line alone to run through a gallon of gas @ 128:1. Overkill maybe but whatever....

Heres a pic of the original tank

 

Well, that isn't exactly the same, but I am planing to do this on my current FC and my FD's new engine. I just like that 2-stroke smell