• Oct 27, 2007
Say what you will about the styling of the Mazda Taiki concept that's currently on display in Tokyo. It's quite possible that what's underneath is more interesting, anyway. Under the hood of the Taiki is a new gen rotary engine from Mazda called the 16X Renesis. Of course, the Rotary engine has its share of detractors, but Mazda's sticking with it anyway.
Further refining Felix Wankel's trochoid wonder, the Renesis (known internally as the 13B-MSP) has been massaged and enlarged for the first time in a very long time. Capacity is now 800cc per rotor, bringing total size up to 1.6 liters. Direct injection allows the 16X Renesis to put out more power and torque while running cleaner than a port injection setup would have allowed. Attention was also paid to reducing the oil consumption that Wankels are known for. The size of the engine is still pony-keg compact, and the rotor housing is now aluminum, which should save a little weight. While the new larger chamber design and direct injection offer more efficiency, it still remains to be seen whether or not the Rotary is capable of modern horsepower numbers without turbochargers (difficult with the side-port design) or swilling fuel like a sailor on shore leave. The 16X may show up in a special version of the current RX-8, or Mazda may hold off until a new RX-8 bows in 2011.

[Source: AutoWeek, Photo: Winding Road]



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  • 17 Comments
      • 7 Years Ago
      Mazda continues to build and offer rotary engines because they can. Other carmakers don't offer a rotary engined car because they can't. It's really that simple.
      • 7 Years Ago
      I'm really looking forward to this, I have a turbo rotary right now, and wouldn't mind some more displacement :). I just hope it turbos decently with the side port design.

      also, a correction to the article... rotor housings have always been aluminum. at least since the 1st gen rx7 in 79.
        • 7 Years Ago
        Exactly right; the rotor housings were aluminum for the 12A engine in my old RX2 sedan and the 13B in my old RX4 wagon (and both of those cars are sorely missed). Dan may have confused the material used on the rotor housings with the center and end sections, which were cast iron for the two just mentioned (as well as the RX7; not sure about the composition of those pieces in the current RX8 Renesis engine)
      • 7 Years Ago
      If Mazda puts this 16x rotary in the 2500lb Kabura concept it would be a 350Z killer!!!
      • 7 Years Ago
      Woow. Awesome concept. I'd love to see one with a 350hp twin turbo like the late, lamented RX-7. Fuel mileage be damned, make it as fast as it is eye-catching.
      • 7 Years Ago
      I read that the 16x is ALL aluminum. This should improve reliability due to having materials with equal thermal dynamics across the board, instead of the former FE-AL-FE-AL-FE arrangement. Next, I read that na electric supercharger is being tested, which should help Mazda achive the goal of 300hp and 300 ft-lbs of torque. The side-exhaust configuration introduced in the RENESIS addressed uninformed-Phil's concerns about emmissions and reliability. I'm all for the new engine, but I still maintain that more is better... more displacement and more rotors. I'd love for Mazda to being a 3-rotor version to the US, but nobody h as made a 3-rotor RENESSIS yet, probably becasue the middle rotor's iron housing would wreak havoc on the adjacent rotor temperature-wise. An all-aluminum varient might fix that. So, a 3-rotor (2400cc), all-aluminm, electically-supercharged RENESSIS w/ direct injection should make 400hp easily, even with being detuned for acceptable gas mileage.
      • 7 Years Ago
      i own and love my RX8 but would love a rotary that burns less oil and gets better MPG. extra torque would rock.

      • 7 Years Ago
      Well more than 200 hp out of a 1.3L non-turbo engine look like real horsepower to me.

      burning oil ? yes, it's the way they are made. Live with it ! can't be worse than a snowmobile.

      reliability : yes they are reliable when not raced. Fact : the late rx-7 wasn't reliable under waranty; Mazda started an investigation to find out that most drivers who buyed a rx-7 took the cars to the tracks. Sure a Toyota corrola is more reliable... but how many are raced ?
      • 7 Years Ago
      Philip, keep in mind one thing. Mazda has the patent for the rotary so other car companies cannot pursue this technology.
      • 7 Years Ago
      Cant wait to see the numbers. Any torque improvement would be greatly appreciated. 300hp @ 9000rpm anyone?
      • 7 Years Ago
      Why don't the finally learn and kill this horrible engine already.

      The rotary is an engineering deadend and Mazda is simply too hard headed to realize this.
        • 7 Years Ago
        I'm not shortsighted. Toyota, GM, Ford, Mercedes all spent millions developing rotary engines. They all came to the same conclusion. It is simply inferior to the piston engine in key aspects:

        It gets very high emissions because of the very poor burn in the irregulary shaped combustion chamber.

        It is very thermally inefficient compared to the piston engine becuase of the high combustion chamber area to volume ratio. Therefore a very large amount of heat is wasted compared to a pison engine.

        Not to mention it has horrible reliability.


        It is not simply about doing things differently. I'm all for doing things differently if they work and are worth it. It this case the con greatly out weight the pros.
        • 7 Years Ago
        I'll bet Phillip can't name the only Japanese carmaker to win the 24 hrs. of Le Mans.

        That would be Mazda, with a four-rotor engine prototype. Reliability? I think it's covered.

        Your emissions and heat criticisms don't apply to the Renesis motor.

        Then there are all the RX-7s raced nearly every weekend of the year.

        So, Phillip, I think instead of killing the motor, Mazda should continue it just to spite you.
      • 7 Years Ago
      I know many don't like the car's design, but I think it is beautiful. It has the kind of unusual surface treatment I remember from show cars long ago.

      And I love the idea of a 1.6 liter. I once had a 13B engines RX-7 - still one of my all-time favorite cars.
      • 7 Years Ago
      Great to see the passenger rotary engine continues to live at Mazda. As a current RX-8 owner, it would be great to see more HP and better gas mileage to a fun engine.
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