Rotary aviation Richard Sohn adapter
 

I am thinking to install this adapter to my fd.
I have hear that I can not install this adapter if I have oem twin turbo setup,Is that true?
Have anyone install this adapter with twins?
Any issues?
Finally were I can buy it I try to reach Richard with email and also I have call him but never answer to his phone or email.
Thanks

Check the forasle section I am selling a lightly used one for alot less. Yes it will work with the twins but the one oil return needs to be modified or the OMP needs to be clocked.

What are you mean the omp needs to be clocked can you please be more specific?
Send me the link from for sale section pls
Thank you

By clocked im sure means flipped upside down or fitted differently then oem no? Has anyone used this on the stock TT setup. What reservoir was used? Where was it mounted? Why isnt this a popular mod in the 3rd gen world like the RX8s. Is it not that much more beneficial than just premixing like a man at the pump?

Yes, substantial modification is required to get this to work with the twins. Ask me how I know.
Essentially, the RA sandwich plate pushes the OPM away from the block. This, in-turn, sets the wiring harness connector directly in the way of the connection between the spool pipe between the block and the oil hard line to the primary turbo side of the twins. One would need to eliminate that nipple and fabricate a new one, such that it clears that connector, but terminates at the same mate-up spot as the previous nipple did. Some people make-up a braided hose, and make an AN adapter set for this. I'm not keen on that, as those hoses don't hold-up as well as a hard spool pipe. This is why I am not currently using the one I bought.

The OMP system on the FD is a lot more robust than the RX-8's and injects more oil. Mazda was trying to cut oil consumption/emissions on the RX-8 and really skimped on the amount of oil metering, so it does make sense on that car.

FD doesn't have nearly the same problem, you can add a little premix to gas to make things happier but really the engine will fail of something else before apex seal lubrication is an issue.

And, as stated, it's a big engineering effort to get that adapter to fit. Just not worth the fight.

Dale

Don't people use the jdm mikuni pump to mitigate clearance issues?

These used to be unicorns. Are they still, or in these days of increased importation of all things JDM, more readily available?

They come up about one a month give or take, and YAJ has one of everything

So no modifications are required with the Mikuni? Just want to be sure before I order this thing.

Firstly, there is no need for this device. It is a solution in search of a problem.

Secondly, no one has established to my satisfaction that the gravity feed supplies sufficient oil to meet the required OMP output at all times. The OMP it draws oil from a supply line coming straight from oil returning from the eccentric shaft. Although this is on the lower pressure side of the system, it is still under pressure and pushed by the engine oil pump. Replacing that supply side with a gravity feed might be enough for the OMP to pump through the lines, but it might not match what the engine normally supplies to the OMP in which case oil flow will be lower than what you get from the factory setup. Has anyone actually demonstrated through back to back output testing that the gravity feed is indeed enough?

Thirdly, you are introducing further complication to the engine bay and another potential point of failure. I ran one of these setups and went to great lengths to design a baffled reservoir that would never starve the OMP of oil supply but I could never really know whether that was the case in real world running. I decided to ditch it altogether and haven't looked back. I am quite happy running mineral engine oil and injecting that into the engine.

If you have any concerns about using engine oil for apex seal lubrication (I don't!) then just premix. Otherwise stick with the factory design.

I was considering for piece of mind. But was also considering just premixing.

I'm simplifying a lot of systems, so figured something like a reservoir and the adapter wouldn't be too much of an addition.

​​​That being said, I can appreciate that you're position on the gravity feed could be questionable. I would still add some premix, if I go this route.

I have one brand new that I may end up not using. The included bolts fit the original omp but are too short for the Mikuni so you'll need to get other bolts or studs.

With JUST premix you need a stand-alone that can adjust off-throttle fuel, otherwise when your injector duty goes to zero, so does hard seal lubrication...often for extended periods and at higher rpms. The OMP is both rpm AND load (throttle) dependent.
No personal experience with the Sohn piece but packaging on a stock car, even with the JDM pump, will still be hurdle. You still need a reservoir of reasonable size. And of course you can NEVER let it run dry.

IMHO the adapter was absolute genius....”was” being key. I just think there’s better options now. And I DO know that R & R’ing the OMP with the engine in the car is no walk in the park with the twins...unless you like building ships in bottles.

FWIW I chose to keep my stock OMP and premix at half rate. To counter carbon from the additional oil I added a simple boost activated water injection system and simply keep my oil changes at a little closer intervals.
The WI system is inexpensive, dependable, requires no special tuning and is way easier to package. On my car it’s also nearly invisible. It also comes with the added benefits of knock suppression and cooling. —-> https://www.rx7club.com/auxiliary-in...ion-fd-959565/
(pics reloaded at the end)
And keeping shorter oil change intervals is a good idea anyway since fuel dilution is almost a given over time.
Caveat: I don’t have emissions testing and those systems were removed. But my Bonez hi-flow cat has been tolerating the extra oil just fine over the years with no air pump. And nobody has reported seeing unusual smoke from behind.
My .02

As mentioned, the only mod is you need a longer bolt (the bolt should have been reversed in the picture, but you should get an idea)

https://cimg1.ibsrv.net/gimg/www.rx7...f8725947a6.jpg
I got mine from Betmetric

https://www.belmetric.com/

I would not have thought of this. It does appear, though, that the OMP still has a suction and discharge end. As such, pressure on the suction end does not necessarily equate to increased pressure on the discharge end. As far as I can tell, the OMP is a positive displacement pump so pressurizing the suction (with standard engine pressures) will make no difference on the discharge end (other than oil flow into the chamber being easier / quicker - which also doesn't matter because the stepper motor controls the opening and closing of the chamber anyway).
All this to say that I believe the RA plate is worthwhile, and still plan to do this with my sequential engine sometime soon.
My idea is to get the AN oil drain flanges (flange x AN male), and have a custom hose made up for high-temperature / high-pressure oil service with steel AN ends. Probably some fittings will be needed to "kick" the house out, away from the mate-up between the turbo pipe and spool piece. I have bigger fish to fry at the moment, though.

I've been running the RA adapter on my S5T2 FC for over 6 years now. The 1st 3 of those 6 years were with the stock ECU controlling the OMP, on my old 13BT, the next 3 of those 6 years was on a new 13BT build that is running on an AEM Infinity ECU. I obsessively measured pre-mix oil consumption from the tank, along with fuel consumption so I could correlate the two metrics and get an average measure of premix consumed per gallon fuel consumed. With the 1st motor & stock ECU, premix consumption averaged about 0.75 ounces per gallon of gas consumed across all driving conditions encountered. I'll add that I didn't retire that motor because of any kind of failure, and I sold it as a used, high mileage running short block after I swapped in my new 13BT build. The new 13BT build that is running on the AEM Infinity has similar premix oil consumption rates, but now I have the ability to fine tune the OMP delivery map to better suit the viscosity and flow characteristics of premix from a gravity fed tank. After about 6 months of doing the same obsessive oil/fuel consumption measurements with the new build, and some iterative tuning of the OMP map, I have it consuming about 1 ounce of premix/gallon gas consumed for normal street use driving; during a hard flogging on the track or a dyno session, I'll see about 3 ounces premix per gallon fuel consumed.

Great feedback on this one, I'm glad to hear about the 6 years of use with good experience. The idea and system makes sense to me, and sounds like it has good real world experience. I'm building right now, so I just want to make accommodations now with the engine out of the car rather than in. Short block is together which is why I'm contemplating accessories at the moment. I have a 98 rs so I already have the Mikuni. Longer bolts is an easy fix thanks for the link! Plan is also to stick with sequential twins for now, but may go bnr or wait till next season to go single (but I do really like the twins, not sold on the single just yet).

Curious what was done about reservoir locations? I'm ditching power steering, so thinking that pumps prior location might be a good spot for the tank.

For my FC, I put a 2 quart tank in the space where the air pump used to live, which was great because it's directly above the OMP, so a pretty straight hose run down to the RA adapter. According to the instructions that come with the adapter, the tank needs to be at least 6 inches higher than the adapter for a proper gravity feed, and from that location, it's about 12" higher.

For the FD project I picked up last year, I put a smaller tank (1 quart) up high just behind the passenger side spring/shock tower where the ABS pump was (no ABS & single turbo in this FD). It's a longer hose run, with obviously more bends in it than in my FC setup, but it places the tank at about the same 12" height above the OMP & RA adapter. Haven't put enough miles on my FD yet to characterize how well its working, so for now I'm running premix with the gas as well as in the tank.

IMO the cons outweigh the pros

Cons being cost (for both the adapter and pump), you need a dedicated oil tank, and you need to keep it filled
Pros being you are injecting clean 2 stroke oil (4 stroke oil is fine for injection and if it's dirty, so what) and that you can then use synthetic engine oil (synthetic engine oil is fine injected)

My 2 cents

But hey, if you're OCD