The Richard Sohn Adapter kit or better the rx8 2 stroke oil conversion kit, is one of the most famous & useful mods to add to your rx8.
The reason behind the use of this mod goes back the design of the series 1 Renesis rotary engine.
The main issue of the rx8 engine is wear. In order to reduce wear, Mazda added an oil injector system that is powered by an oil metering pump (OMP). Depending on the engine load, this pump pumps oil in the combustion chamber in order to increase lubrication of the apex seals and rotors, thus prolonging their life and making the engine last longer.
Top 3 lubrication issues with the stock Renesis engine:
- Lack of lubrication
- Quality of lubrication
- Engine oil restrictions
Mazda put only 2 oil injectors, which didn't turn out to be enough. On top of that, the OMP pumped the existing dirty engine oil inside the chamber, that increased carbon deposits.
And if this wasn't enough, mineral oil was the only "safe" oil you could put in the engine, as it burned cleaner than full synthetic oils, which are more resilient to heat and because of that leave more deposits.
Increasing oil thickness was also an issue as if you used an oil that was very thick, such as 15w40 or 20w50 you seriously risked to clog the OMP lines, as the oil would've been so thick that the engine would get little to none to lubrication itself.
Why install a Sohn Adapter?
Here is where the Sohn Adapter comes in. The purpose of it, is to work as a sandwich between the oil metering pump and oil delivery source. The sohn adapter cuts out the dirty engine oil and provides a new entry for clean fresh 2 stroke oil, which lubricates better and burns cleaner.
Since the main engine oil is now only there to lubricate the rest of the engine and not to burn, you can use any oil you want. The main benefit here is that you can ditch the original recommended 5w30 mineral oil and use a Fully synthetic 10w40 or higher (20w50) oil, that will give a superior protection to the engine and make it last longer.
What's in the kit?
The kit contains 2 bottles (oil + washer fluid) that will replace the big one holding the washer fluid. You can install them on the convenient cut to size plate that comes with the kit, along with the bolts to secure everything in place.
You will get the sohn adapter itself with a cardboard washer, that will require some small cuts on top to get fitted, and extended bolts to bolt it to the OMP. Hoses and clamps also included.
The installation will require some special tools to make it easier or even possible due to the location of the OMP, so be sure to check out my video to see which ones you'll need.
Price: Medium 2/3
Install Difficulty: 4/5
Bang for buck: 5/5
So is the Rx8 Sohn adapter worthy? Hell yes! The only downside is that it can only be ordered from the US, so for outside buyers there will be an import tax. But in the end, it will be well worth the price.
A Sohn adapter is not a replacement for premixing. This adapter solves the oil Quality issue, but the oil quantity issue still remains, and that's where premixing comes in.
Watch hwo to premix your rx8 here.
To finish, check out my Step by Step install video below: