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RX-8 Power: how powerful is the Renesis really?

We have all heard the magic disappearing horsepower numbers from the marketing sources. The question we’d like to pose isn’t “where did the horsepower disappear to”? Rather, we’d like to ask, how much more power does the Renesis make compared to it’s predecessor?

Keeping in mind that Mazda did not increase the displacement of the Renesis, and they managed the amazing engineering feat of reducing emissions at idle to 10% of what the 13B-REW (the Renesis’ immediate predecessor) produces at idle, and 15% of what the 13B-REW produces at cruising speeds and loads.

The argument can be made that the Renesis produces higher peak power because of its ability to rev much higher than the old 13B. So to be fair, let’s compare the two powerplants at the point where the old 13B is producing it’s maximum hp. In this chart, that happens to be at 7000rpm. At this point, the old 13B is making 125hp while the Renesis is making 175hp. That is a 50hp difference which translates to 40% more power (40% of 125hp = 50hp). For the sake of full disclosure, the 2nd generation RX-7 tested here is a 1991 with a fresh motor (less than 1000 miles), and the RX-8 tested is a 2004 with about 800 miles.


Dyno chart comparing stock Renesis and the last generation
normally aspirated rotary engine found in an 1991 RX-7.
Click the above image for a closer look.


While we realize that 12 years has elapsed since the previous generation normally aspirated 13B was last sold; that there has been at least that amount of research and development devoted to the Renesis, we should not lose sight that Mazda is the only company actively perfecting and producing the rotary engine.

And we are ecstatic that the rotary is back. Next, finding more power in the Renesis. Stay tuned.


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