For our motors, two stroke engine oil (injection type sohn OMP adapter or premix) should be used. The denominations JASO “FC” or “FD”, FD being the best for 2-stroke high temperature and high-performance. At Derwin Performance, we use Klotz JASO FC. You can also use Motul 710 or 800. We recommend Klotz as it is better and cheaper than Motul, and yields better results overall.

For the premix, you can add 2 stroke oil at a ratio of 30-40ml/10L of fuel while still using the Oil Metering Pump system. If you fill up halfway, cut the oil number by half. For engines running without the Oil Metering Pump system, we suggest 100ml/10L of fuel up to 120ml for track or with watermeth injection systems.

Motor Oils

For motor oils, we need a minimum viscosity of 10W30 (never use 5Wxx). For more aggressive use and/or racing, opt for 20W50.

Under new regulations as of January 2013, Mobile 1, Castrol Syntec and Shell Rottella all now have a API SN designation. WE MUST NOT PUT THESE OILS IN OUR ROTARY ENGINES. SN means reduced anti-wear additive (ZDDP < .075ppm) and is replaced with anti-friction. Anti-wear and anti-friction are two very different things!

For oil changes, use only API SJ or SL at a minimum. (see figure #1, API donut on the bottle). They contain at least .1500ppm (SJ) .1000 to .1100ppm ZDDP for (SL). This is ideal for our rotaries as it increases the fit between segments (Apex) and reduces wear. We see an increase in vacuum and sealing of the motor overall, and an increased lifespan.

Always use non synthetic mineral oil for rotaries (note, it is really only the additives that are synthetic)

Synthetic oils are for suitable for rotaries. OMP or not, premix or not, they don’t have the ZDDP (Zinc Dialkyde) necessary for rotary engines. The additives they contain are simply not enough. Furthermore, when synthetic oils reach high temperatures, they varnish and create deposits in the motor, damaging the bushings and internal rubber joints. There is no advantage in using a more expensive oil that has no advantages. It is necessary to do your oil changes at the same interval, between 3000kms to 4000kms maximum. For example, Brad Penn oil (mineral with synthetic additives) It is less expensive and has all the characteristics needed for rotary engines. The advantages are obvious, as your motor will start better, run better and smoother.

There is one notable exception for using a synthetic oil in a rotary. In cases where the motor is being races, and therefore rebuilt every month or less. The varnish cause my synthetic oils would then be cleaned. All is dependent in the frequency the motor will be opened up and cleaned. THIS IS THE ONLY EXCEPTION.

If you use oil with the API classification “SN” (even if the manufacturer attests that it meets the old SJ and SL standards, you must add a zinc addictive (ZDDP) with each oil change. SN oils don’t meet the zinc (ZDDP) content needs. Since January 2013, zinc content was reduced in order to meet API standards and government requirements with respect to prolonging catalytic converter lifespans, and this, at the detriment to the life of our motors.


Torco ZDDP Plus Oil Additive
Eastwood ZDDP Plus Oil Additive
Zddplus ZDDP Plus Oil Additive

OIL FILTER (to be replaced with every oil change):

The best are:
Nippon filter co. (MAZDA), K&N

To sum up:


Motor oil: BRAD PENN Green performance Mineral oil with synthetic blend

Oil filter: MAZDA, K&N

All available through DERWIN performance: derwin@derwinperformance.com