Rotating Masses: Getting To Know The RENESISFor those of you who are unfamiliar with the rotary engine, we must tell you that it cannot be considered anything less than a masterpiece. In terms of combusting air and fuel, it shares the same responsibilities as a piston engine but achieves its task in a much different manner. For almost 50 years, the rotary engine has awed the world with its ability to make enormous power with minimal displacement. Unlike a piston engine, the rotary design is simple and consists of only a handful of components.
It wasn't impossible to extract 255 horses naturally aspirated if you had a serious port job, but such a setup lacked torque due to its tiny displacement. Fully built turbo versions have seen unheard of figures when compared to any 1.3L engine in general. It was a task and a half to get these rotaries to idle smoothly, much less idle at all. Welcome to the new realm of rotaries, the RENESIS. And before you ask, they came up with the name by combining the words "rotary" and "genesis." Although the previous 13B-REW motors were remarkable, they were never thought to be perfect in terms of tuning, efficiency, and producing power. With the RENESIS engine, Mazda has just taken a few steps closer to perfection. The most crucial change in this engine's design is the use of the side exhaust ports rather than the former peripheral ones. These new exhaust ports eliminate combustion overlap, which is when exhaust gases get mixed in with fresh intake and fuel only to be combusted again. That is caused by the intake port opening before the exhaust port gets a chance to close, and that is a definite no-no when it comes to efficiency. With overlap eliminated, you can achieve more power, less fuel consumption, lower emissions, and increased efficiency all around. On the high-performance model there is also an additional intake port that opens after 6,250rpm. The result of the newly designed RENESIS is a smooth idling 250hp @ 8,500rpm and 164lb-ft @ 5,000rpm.
The beauty of driving a rotary engine is found in its ability to maintain constant power from 2,000rpm and up past 8,000rpm. Being able to keep the car in Second and Third gear came in extremely handy when taking the tight turns at Laguna Seca. On the highway, we never even shifted into the newly acquired Sixth gear. But knowing it was there for use at our discretion did make us feel a little more at ease. Not too many cars are this fun to drive.
Is there a turbo version? Not that we know of. We asked several hundred times during the course of this launch, although the head engine designer told us that the RENESIS is completely capable of withstanding some forced induction. But before you go off and buy a turbo upgrade for a 13B-REW, we're obliged to warn you that it won't fit since the side exhaust ports require a completely redesigned exhaust manifold. In fact, the new model is limited in space, which makes it difficult to add a turbo. This is very sad news indeed. As smooth as this car drives, it just doesn't feel the same without boost, that tingling feeling in the bottom of your gut. Hopefully, Mazdaspeed has something up its sleeve because nobody else seems to.