Not taking sides on synth vs dino - there are probably great dino racing oils that are not suitable for street use. But you're pointing to something irrelevant for your argument.

All Rx-7 have to pass emission testing in order to be certifiedfor sale in the USA and Emission testing is done on mineral oils. Because rotary uses oil injections, Synthetic oil could reduce the life of the emission components such as catalytic coverters and o2 sensors. These parts has to pass 50,000,80000 and 100,000 miles durability testing,which was performed with minerals oils. The Rotary burns oil to lubricate the apex seals, and synthetic burns at a higher temp than mineral oils. Repeated shorts trips may cause the synthetic oil to build, leading to spark plugs fouling. Finally oil sparyed inside the rotor cavities can contact the rotor oil seal " O " rings and oil inside the combustion chamber can contact the housing seal "O" rings. Long term exposure to synthetic oils may cause these seals to swell and deteriorate,resulting in an exchange in engine. This Y mazda does not condone the use of synthetic oil in Rx-7. Also Y SCCA Racers use synthetic oil and y can I use it? Cause Racers synthetic oils for many reasons: Racers frequently tear down and inspect their engines,thus replacing all seals, Racers do not need emissions certifications, Racers cars are not covered under warraty. Oil in the i/c and air supply hose on all turbo rotaries is a normal functions of the pcv systems to control blow by. During boost , the pcv valve closes and boost pressure from manifold is directed through the engine housings,oil filler neck and into the air intake funnel in front og the front turbo. From there it passes throught the front turbo and into the i/c and throttle body,This coats all intake air system with oil and is an indication of a NORMAL OPERATION od the pcv system. This is not a defect. I hope this answers most people Q about synthetic oils.

Many years ago (1993) in discussing all the minor problems I was having with my FD (bought new in Aug '92), I discussed this directly with the guy who runs the Mazda service tech training school in Pleasanton. He and I got on the phone with an English-speaking engineer in Japan. The gist of that conversation was that the main reason Mazda does not recommend using syntheitics is because they did not want to (or have the money to) test all the different blends out there. They agree it's better for the turbo, but for the reasons you note, there could be some synthetics that would cause problems. The engineer agreed that most would not, but was not willing to divulge any that had been tested and cleared. In a sense, if you're using a synthetic, it's a crapshoot.

Because rotary uses oil injections, Synthetic oil could reduce the life of the emission components such as catalytic coverters and o2 sensors. These parts has to pass 50,000,80000 and 100,000 miles durability testing,which was performed with minerals oils.

The Rotary burns oil to lubricate the apex seals, and synthetic burns at a higher temp than mineral oils. Repeated shorts trips may cause the synthetic oil to build, leading to spark plugs fouling.

Finally oil sparyed inside the rotor cavities can contact the rotor oil seal " O " rings and oil inside the combustion chamber can contact the housing seal "O" rings. Long term exposure to synthetic oils may cause these seals to swell and deteriorate,resulting in an exchange in engine.

This Y mazda does not condone the use of synthetic oil in Rx-7.

Also Y SCCA Racers use synthetic oil and y can I use it? Cause Racers synthetic oils for many reasons: Racers frequently tear down and inspect their engines,thus replacing all seals, Racers do not need emissions certifications, Racers cars are not covered under warraty.

Oil in the i/c and air supply hose on all turbo rotaries is a normal functions of the pcv systems to control blow by. During boost , the pcv valve closes and boost pressure from manifold is directed through the engine housings,oil filler neck and into the air intake funnel in front og the front turbo. From there it passes throught the front turbo and into the i/c and throttle body,This coats all intake air system with oil and is an indication of a NORMAL OPERATION od the pcv system. This is not a defect. I hope this answers most people Q about synthetic oils.