Last month when I dropped my car off to get the turbo installed I had a chat with Dave from KDR/Speed1 which eventually came to the topic of the SOHN adapter. He was saying that the issue with the SOHN adapter is that it is gravity fed unpressurized oil verses the oil coming from the oil pan which is hot and pressurized. I'm not sure I was understanding him correctly but I believe he was saying that the OMP was more of a solenoid than an actual pump.

I just wanted to get some feedback on how the lack of pressure and heat would affect the OMP using the SOHN adapter verses stock.

 

He really said that? Doesn't he build rotaries?


The SOHN adapter has no effect on the pressure it is injected at, the Oil metering pump is still in place and the 2 stroke being fed is being injected into the combustion chamber so it's temperature is of no concern. Think about how hot it is inside the combustion chamber.

Ask yourself, do you want dirty motor oil that is design to resist burning off (especially synthetic) or do you want clean 2 stroke that is designed to be burned injected?

 

This was more than a month ago and I started this thread because other OMP discussions triggered my memory. If anyone is ignorant on this stuff it would be me and I'm sure I am misinterpreting what he was talking about. I was just reiterating what I thought the discussion we had was. Also the heat was more from my own analysis, he mentioned only pressure.

 

The adapter goes between the block and the OMP. The OMP still does the pumping to the oil injectors. The SOHN does not affect that. The only concern I have (not really a concern honestly) is about the temp of the Idemitsu I use is that it is too cold and thick possibly at startup to flow from the SOHN reservoir. But once the engine is warmed up, so is the SOHN reservoir and the hose to the SOHN adapter.

But once the 2 stroke enters the SOHN adapter and then the OMP, it gets plenty warm.

 

The S2 EOMPs are very different BTW so if you have 2009 or 2010 Sohn may not work.

9krpmrx8, I was thinking of wrapping my heater hose and oil tank line together to pre-heat the two stroke oil.... thoughts?

 

Sohn will not fit or work on a Series II Engine (2009,2010,2011).

Although the S2 is still a 13B Renesis (II) ALL engine parts are not the same or interchangeable.

The ONLY engine parts that are the same (S1 and S2) are the actual internals that are connected to the eccentric shaft like, rotors, apex and corner seals and their springs, Oil Control Rings and Springs, Bearings.

Rotor Housings, Front Timing Cover, all Irons, Oil Pan, Oil Pump, EMOP and related, Water Pump are unique to Series 2.

 

That is a good idea as long as teh hose you are using for the SOHN is thick enough, I had been using clear hose but with the heat I see it gets too brittle and hard too fast. If I lived in a cold weather environment it would be a concern. Plus I did a pour test recently and found the Idemitsu flows pretty well when it is near freezing so I am pretty set on sticking with it.

 

this is actually imho a good question.
The oem does not inject--it only provides a oil drop then the seal passing by wipes the oil away. So it is a very low pressure system.
BUT--the question to me is the oil delivery to the omp. With the Sohn it is totally gravidy dependant. So any kind of obstruction/partial obstruction (bent line whatever) could cause trouble? Plus I do wonder about a thick oil in the cold weather that may be a little harder to freely flow?
I dont think there has ever been a case of a malfunction of this sort--at least that I am aware off--so its probably a mute point?
OD

 

Yeah I have not heard of a failure either but my reservoir flows pretty well with just gravity. I am actually having an issue with my OMP right now, I am not getting any OMP CEL or limp mode but I have noticed the rate of my reservoir emptying has decreased significantly but yet the Cobb shows the OMP rate at normal rates. I have removed and checked the SOHN, hose, etc. and everything is flowing and seems to be working fine. But in the meantime I am premixing 1oz a gallon just to be on the safe side until I fork out the cash for a OMP.

 

MazdaManiac has been using a Sohn OMP Adapter on his boosted Renesis for YEARS and, IIRC, using Idemitsu with it.
I have been using a Sohn OMP Adapter for YEARS with my ported/nitroused Renesis and I have mainly used Royal Purple 2-Stroke with it (and an occassional excursion with any 2-stroke I can get my hands on, like Pennzoil/Walmart stuff).
BHR has the Sohn OMP Adapter placed third on our list of highly-suggested mods for the RX-8.
If cold temps are an issue, you can use snowmobile 2-stroke like I did back in MI, and I used Yamaha stuff (sometimes the "pro" oil) as it is made for injection systems AND extremely low temps.

What more need be said?

 

Two possibilities; 1) Your OMP nozzle vents are clogged. 2) Your OMP nozzles/check valve(s) are clogged. It happens.

 

I'd like to see Jeff chime in regarding attaching a vacuum source to his OMP tank and the results he experienced.

 

I'd like to see him chime in too since he raised questions and doubts at the last seminar about direct injecting Idemitsu oil as opposed to pre-mixing it as the manufacturer intended. The above statement kind of surprised me.

 

Can I clean these if I remove the OMP? By OMP nozzles/check valve do you mean the oil injectors themselves?

 

No, they are inspected/cleaned by removing the UIM and accessing them.
Yes, the injectors, themselves.

 

Thanks, I might have to tackle that over the holidays. what do you think would be best to use to clean them?

 

I may be wrong about MM and the Idemitsu.... (oil conversations always invoke much discussion)

Having used all different kinds of 2-stroke in my tank, my own opinion is that it really doesn't matter much what we run in the tank as long as it is dedicated 2-stroke (and I haven't been desperate to need to run crankcase oil in it but I bet that would work, too). Whether or not it is specifically designed for injection hasn't seemed to make a difference.

Then again, I have also accidentally run my OMP tank dry for a few hundred miles and everything is still fine...... my engine runs as good as it ever has.

 

Probably carb cleaner but, more importantly, you should test the check-valves in them by blowing through the vents. Not compressed air, though.

 

Jeff and I have not discussed this particular issue in a couple years, and he has not mentioned anything to me since, but my guess is (since the factory OMP system relies on pressure delta between atmosphere and engine vacuum) that he has much better/more predictable OMP flow when his oil canister references his manifold pressures. Much in the same way that fuel injection system pressure should account for rising intake manifold pressures in boosted applications.

 

Have you thought about rigging a Battery Warmer around your reservoir?? Just a thought

 

Does anyone have a picture of the oil injectors? I searched but can't find any.

 

You mean you have been wrenching for others WITHOUT a factory service manual?!

What kinda enthusiast ARE you!!??

 

FSM? WTF is that?



I actually have one, I guess I'll have to look there for a visual.

 

Geesh, what a crappy diagram :LOL:



But I found it:

Oil Nozzle Inspection

1. Remove the oil nozzle.

2. Use a vacuum pump to apply a vacuum of 66.5 kPa {0.68 kgf/cm2, 9.65 psi} or more on A of the oil nozzle and verify that vacuum holds:

• If the vacuum drops 2.66 kPa {0.027 kgf/cm2, 0.39 psi} or more in 1 min, replace the oil nozzle.



Thanks Ray, I am out of it, it never occurred to me to look at the FSM

 

That diagram is not even correct!

Remove the UIM and you will see all four oil injectors threaded into the housings near the fuel injector rails. Kinda.