Could this be true

[440Magnum]

Mazda doesn't recommend synthetics for the Wankel engines in the RX-8, but it has nothing to do with the O2 sensors. It has everything to do with the rotor tip seals. Wankel engines deliberately burn a small amount of engine oil by pumping it to the rotor apex seals to keep them lubricated. Synthetics leave deposits that apparently will eventually cause the apex seals to fail. I don't know if this applies to the group III+ synthetics or not (I doubt that it does, its probably just PAOs) but if I had an RX-8, I wouldn't push my luck!

 

[Eddie]

doesn't anyone read the owners manual recomendations? Are some of us just too much smarter than the factory engineers? This thread was hijacked I think because the origonal comment was directed at Mazda TURBO engines. I thought only the Speed 3 and CX7 were the only turbo engines in the Mazda lineup.

 

[Klutch9]

they are. of course mazda made a 2.0 turbo engine for the Mazdaspeed Protege' and Mx-5 (i dont think they were the same motor, since one was mounted transversely and the other longitudinally...) but those aren't made anymore.