For starters, the SkyActiv-R rotary engine is rotated 180 degrees. This brings the exhaust port on top of the engine. The intake, on the other hand, is located at the bottom. Why did Mazda engineers choose to do things this way? The explanation is a rather simple one.
Provided that the intake is located below the engine and the inlet manifold is long enough, performance should be top tier. As for the exhaust port mounted on top of the engine, this should offer a shorter passage for the exhaust gas to exit the engine into the turbocharger(s). And yes, the turbo housing is mounted on top of the exhaust port. Now that’s innovation. The engineers sure deserve a big fat Christmas bonus.
The patent application outlines that the intake has a common passage and independent passages, which translates into an advantage “in obtaining a dynamic forced-induction effect caused by an inertia effect.” Another passage that is worth mentioning is the one about the exhaust manifold “having independent passages and a manifold passage. A length of the exhaust passage becomes comparatively short, and thus, a passage resistance in the exhaust passage can be decreased.” What does this all mean, then?
From what I understand from the gibberish lexicon used in the patent application, the replacement for the Mazda RX-8 will have a Wankel that isn’t just a packaging marvel, but also promises a lot in terms of performance. It remains to be seen if the Japanese carmaker will enhance the SkyActiv-R rotary engine with one or two turbochargers. Fingers crossed it will be a duo because more is better. Always.
P.S.: March 2018 marks the 40th anniversary of the Mazda RX-7.