The Mazda RX-9 won’t have a rotary engine
The exhaust port on the 13B-REW used in then FC and FD for comparison. The port is located on the housing and is considerably larger. Great for driving turbine wheels. Guess which port flows more between the two.


Two-stroke piston engine cylinder uses ports instead of valves much like a rotary. This is also part of the reason you only see 2 strokes in 350cc or smaller dirt bikes these days.

So instead, what will we get? Well, Mazda doesn’t produce any sporting engines other than what’s in the ND Miata. The RX-9 will surely be heavier than the ND, so that likely won’t work. They don’t even produce a six-cylinder engine anymore. Mazda’s company slogan is Skyactive, whatever the hell that means. So I suppose what we should expect is a modern chassis, meaning something 3000-3500lbs. Two or four seats, 2 doors, a body with a high belt line, small windows, and big pillars for crash structure integrity. A Skyactive 4 cylinder engine at the front, and maybe a 6-speed manual gearbox if we’re lucky and a price tag of roughly 45 to 60 thousand dollars. Doesn’t sound all that compelling when Americans build great chassis stuffed with big snarling V8 engines for similar money; Germans will build you a turbocharged straight six-cylinder rocket with sharp handling, or Japan can offer you that German thing with a Toyota badge.

Mazda’s most powerful engine. A 2.5L turbocharged 4 cylinder producing 250hp. Subaru’s 2.5 turbo 4 cylinder has been making 50 more hp for 15+ years. Not exactly exciting for the enthusiast.

Fanboys everywhere know Mazda will have to find a way for the rotary to work in order to use the RX-9 nameplate and do it any justice. This fanboy agrees, but unfortunately doesn’t see it being a possibility.




    1. Whoever did the rendering is clearly a fan of the FRZ/86 styling. An 86 with an LS would be a pretty good leap in that direction; should that be the next MotoIQ project car?

  1. Even though nowadays most car makers have no respect for the history behind the names of their cars, I really hope Mazda won’t call a car RX if there’s no rotary engine in it.
    Also, I hope I’m mistaken, but it seems very unlikely that Mazda will design a sports car powered by an ICE in the near future. Latest patents from the brand tend to show that it could be an EV with a rotary power generator like the MX-30.

    1. Lots of patents get filed that never make it to an actual physical model. That being said, I’d love nothing more than to be wrong.

    1. At that point, you could just put a Mazda-styled nose on a BRZ and call it a day. Then swap in a LS, and make Mike happy too (see above comment).

      I’d agree though, there really isn’t much to get excited about in the current Mazda engine lineup that would lend itself to a RX-9.

  2. Two things.

    First off, the NA 13Bs and even the Renesis closed off extra ports, affecting port timing in essentially the same way as 2-stage cam profiles, ala VTEC. This dates back to 1984.

    Secondly, the actual big efficiency/emissions thing isn’t burning oil, it’s inertia stratifying the intake charge in the combustion chamber leading to a mixture that varies from leaner than optimal towards one apex seal, to rich beyond combustion limits at the trailing apex. And then on the older peripheral exhaust engines this gets dumped straight out the exhaust port. On the Renesis, it gets recirculated… but moving the exhaust ports to the side means that heat flux is killing the temper on the side seal springs.

    This, by the way, is why so many “concepts” using rotaries are hydrogen fuelled – because that issue doesn’t apply when the fuel is roughly the same density as the air.

    I guess I just expected original content, even ignoring those points; I’ve seen articles like this about the RX-9 since the RX-Vision concept in 2015, and articles on how the rotary is dead back about 10 years before that. Yes, if Mazda is building a halo car there’s no indication in public as to what it would use as a powerplant, and yes, a lot of signs point to that no it wouldn’t be a rotary if they were. Since nothing in their lineup would work for a halo car, it would be interesting to see educated speculation as to what they could be working on would be interesting. Or heck, given it’s all the rage, talk about technology sharing agreements they have going on where they could be licensing powerplants with other manufacturers that could lead to a halo car powerplant. It’s not like Mazda is ignorant of what exists in the marketplace, nor of their own capabilities relative to larger companies.

    1. Thanks for the great insight Dan! I think you’re probably correct on Mazda resource sharing with another company to develop a drivetrain for the car, as much as I’d hate to see it be anything other than rotary powered.

      1. There’s rumors of Toyota and Mazda collaborating on a straight 6 using Mazda’s Skyactiv-X tech going around recently, so that’s one potential. In reality, who knows?

        Don’t get me wrong – I’m a rotary fan to an uncommon degree but the odds aren’t in favor barring some previously unknown wrinkle in tech.

        1. I’d say direct injection combined with oil level sensors and hybrid systems could solve almost all of the problems with rotary engines.

          Of course, not on Mazda’s budget.

  3. It’s always fun to day dream about the next “RX-9″… but I feel we only have two real choices if they keep everything in-house.

    A) It’ll be a taught up skyactive engine that produces in the neighborhood of 300hp, hopefully still allowing an option for a proper manual (not likely). Puts us in the $40-50k ballpark

    B) It will go the way of the NSX and all-in on the electric powertrain with crazy dual motors backed w/ some small combustion engine and push the price into $80-100k territory. Not a chance of stick shift here and sadly not a chance for most consumers.

    End of the day, I’m all for whatever comes out as long as it looks this good. Even if that means I’ll never own one, someone will, and we could all use this sight on our daily commute filled with drabs of crossovers and SUVs.

  4. I think automakers’ problems, particularly Japanese automakers, is that most people in product planning are not car people and are clueless. When possibly by mistake they make a wonderful car, the next version suffers from content creep and is a mess. That’s why Japanese makers lose their DNA and keep on making appliances. The NSX is a case in point. The new NSX should have used today’s technology with the DNA of the old car to make a lightweight 4-5 liter NA high revving engine with 500-550 hp with the performance target to exceed the Porsche GT3. Honda could have easily done this and the fans of the old car, including the adult kids who grew up dreaming of having an NSX that could now afford it would have bought them in droves. Instead, they built a car no one wanted alienating the fans of the car. Notice now that Japanese car fans are mostly into old cars?

    1. I think (I may be biased) that Mazda is doing better than most, but honestly given their resources I’d be surprised if they’re going for a halo car.

      But given as how I’m playing with early 80s RX-7s maybe I’m more accidentally proving your last point than anything.

    2. Good example. I felt very much the same way. Honda built another ‘daily drivable Super are instead of ‘fun, light, engaging, daily drivable super car. This was a huge failure as modern cars require so little compromise that most Super cars have become truly daily drivable.

    3. The new Corvette is realistically what the NSX should’ve been: parts-bin-engineered mid-engine supercar at attainable prices. What we got was a bloated gimmick-mobile like you say.

      1. I’ve never really thought about it that way, but you’re right. I think the upcoming z06 trim corvette is going to be really special.

          1. I can’t imagine GM going that route, but I could be totally wrong. I see an LT5 from the C7 ZR1 with maybe additional electrical power. As usual, I hope I’m wrong though.

        1. Bummer is most of the Japanese car companies have the ability to make these cars, just zero desire or internal drive. Nissan was going downhill then ze French finished them off. Now, I’m bummed when that’s all that’s left at the rental lot (hell, a Malibu is more appealing than an Altima). Honda built the Type R, then the design team watched Fast and the Furious 300 times and came up with that hideous bodywork. The NSX could’ve easily been a 4-500hp turbo J-series for under $100k, instead we get this ridiculously overpriced and overcomplicated douche-mobile. Toyota doesn’t build anything in-house, just provides some input to other manufacturers to build their cars.

          German cars were where it’s at, but content creep and bloat is turning them into gimmick-mobiles.

          Most of the fun cars are built by American companies these days.

          1. I agree with all of your sentiments Steve, but I must admit, I’m coming around to the CTR’s looks.

            Germans make amazing cars, but they’re all running to a center point of being the same car by different manufacturers. All the fast German stuff is powered by 4 liter TT V8 ‘hot vee’ engines with 8spd gearboxes, AWD and so much sound deadening you can’t even tell what’s thrusting you along at 200mph. Not to mention unless you’ve got $120k, you’re not getting any of those.

            American cars though….man. I’m proud right now. Sixth gen Camaro SS 1LE and ZL1 1LE are monsters, GT350 from Ford is amazing, C7 Z06/ZR1, C8 corvettes if you’re into DCTs. Everything dodge/SRT makes is gold in terms of fun. Everything can be had with a 6.4l 485hp naturally aspirated v8, or if that’s not enough opt for a 6.2l supercharged v8 making AT LEAST 707hp. Hard to argue with fun like that. Need a sedan – they got it, want a coupe? They got it…sort of. Need a jeep with 700hp? No problem. Oh, you have 3 kids and need 3 rows of seats and the ability to pull a boat but still want 485hp v8? Sure, here. And it’s all so very affordable (for a reason I understand) compared to the German stuff.

            That list alone is insane compared to what I came up with when a v6 Nissan Maxima made more horsepower than a v8 mustang GT and american cars were laughable. So much has changed.

  5. I did hear that Mazda was working on a skyactiv inline six-cylinder engine for a rear-drive layout.

    Although the article suggests this would be more for a big sedan, this could be a sweet engine for an RX replacement. If, as the article states, it is based on the Skyactiv-X, this might result in a 3.0L with about 270 hp. While last I heard Mazda is still saying that Skyactiv-X will come to the US, this yet remains to be seen.

    1. If they did come in with an in-line 6 in the 300hp range, itd have to be significantly lighter and different than the current BMWs/Supra to make it really worthwhile. Especially keeping in mind the B58 and S55 in those cars make nearly 400hp.

  6. Fun fact, related to the picture caption about not seeing 2-strokes in anything but sub-350cc dirt bikes:

    You can go to your Evinrude dealer tomorrow morning and buy a 300HP E-TEC 2-stroke, 3.4L V6 with an ECU, triple throttle bodies, and a direct injection fuel system. They’re one of the cleanest burning outboards on the market, and still have the power to weight advantage that 2-strokes are known for. Not clean enough for the road most likely, but a world away from a carb’d dirt bike.
    They still have reed valves, and oil injection (100:1, expensive low-ash stuff), run on pump gas, and they are a badass engine to put on your boat. I have a 150HP E-TEC with 1700 hours on it, that’s been trouble free for the last 9 years since it was new.

    Also, I’m expecting Dave Coleman to suddenly materialize to defend the honor of the Mazda name. Where is that guy?

    1. 2 stroke is definitely still relevant in the marine world, but I’m not sure what their emissions are like compared to road cars. I’m sure the duty cycles and such are vastly different t given the use cases.

      I’d love Dave Coleman to pop up and smack me with an behind the scenes photo of a clean burning turbocharged rotary theyre currently developing! His writing has riveted me for almost 20 years now.

  7. I have owned 12 RX-7’s and one RX8 and need to have my bucket list fulfilled with another Mazda rotary engine car before I go.

    1. You’re a sucker for punishment. I’d love a nice FC turboII or FD. The RX8 felt like such a turd compared to the other cars of that vintage.

  8. I just had a thought that would solve much of the rotaries emissions problems that is possible with today’s technology. Direct injection with a staged stratified charge injection strategy. I wonder why Mazda has not tried this, it seems like a no brainer.

    1. Pratt and Whitney Canada have been patenting a bunch of rotary engine stuff the last 5 years; I’d have to dig into specifics if it was just heavy fuel or also spark ignition stuff. Also Curtiss Wright did stratified charge stuff back in the day. I’m just wondering if someone beat them to it and patented it.

    2. We know you have contacts…make some phone calls. But I’ve got to think with as common DI is these days Mazda has considered that. They already produce turbocharged DI engines for their SUVs.

  9. I have a driver’s license, which is how you know I’m old enough to remember when multiple magazines all showed different renderings of the next (now current) MX-5. None of them looked anything like what we actually got. A quick google search for “RX-9 concept” shows that the image at the top of this article is at least as old as 2018. I’d bet a set of Hoosiers that some kind of concept for the “next RX” gets sketched regularly by people who actually work for a Mazda styling studio, and they are better at not leaking said sketches than people who work in DC.

    I just hope that if they do build another RX-like car, they will make the interior have as much leg and head room as the ’79 RX-7.

  10. There’s almost certainly a new rotary in the works.

    “The technology development is under way [for a range extender hybrid],” said MX-30 program manager Tomiko Takeuchi.

    The MX-30 is Mazda’s first pure electric vehicle but will also spawn hybrid models, including at least one that uses a modern version of the rotary

  11. I’d love to see an auto company have a go at developing the liquid piston engine.
    If you believe the advertisers, it overcomes some of the Wankel’s problems by using static apex seals and relatively static combustion chambers.

  12. I had variable intake timing in my 12A halfbridge. The mild(ish) center ports went to the Webers’ primary barrel, the bridged outer ports went to the secondary barrel. Half-throttle was fun, full throttle was insane. The comparison between apex seals and piston rings is poor. Your side seals and corner seals are for oil control. Apex seals only separate the combustion chambers. I lost the small end of an apex seal once. The engine idled like crap, but above 2,000 rpm it ran just fine and didn’t smoke.

    All that said, a rotary would be effective as the powerplant for a hybrid setup – if the engine were designed to run solely as a powerplant for a generator, i.e. running at a constant rpm for fuel efficiency and torque. Unfortunately, that would take all the fun out of it.

    1. Let me get this straight. You had a carburetted rotary, with VTEC.

      Did it… work? Because I love the idea. It’s like my 1.8 twincam Mk2 Golf, which had a tiny primary throttle and a big secondary throttle, that only began to open after like 2/3 of pedal travel. It was so satisfying to have the noise and the power arrive, while simultaneously the throttle pedal gets heavier.

  13. This is what Mazda needs to do for the RX-9:
    • 2+2 Chassis based on the ND Miata but w/ a longer wheelbase
    • Weigh <3000lbs (shouldn't be too hard since the ND is ~2400lbs)
    • N/A 1.6L 2 rotor w/ direct injection @ ~300bhp & 9k redline (aka their prototype 16X engine)
    • Mild hybrid system (Honda IMA style) to boost fuel economy, reduce emissions, & extra torque
    • Various modes for the electric portion so user can choose between full on/off, eco, regen, zoom zoom, etc…
    • 6 speed manual absolutely must be offered
    * Optional: MazdaSpeed version that adds a 3rd rotor or FI (either turbo or centrifugal s/c) @ ~450bhp & maybe remove hybrid parts for this version

  14. Everyone has their idea for the Wankel comeback… many of these dilute the sportscar soul (i.e. as a range extender or adding battery weight for a hybrid).
    Mazda should look at all the racing upgrades that find their way into successful race engines and what they did with the R26B.
    Forget the average consumer, they don’t know shit, all they want is the latest tech gimmick.
    Design a rotary for the real enthusiasts: based on the “torquier” 16X, seperate clean burning 2-stoke oil injection, stronger studs, ceramic based coatings and ceramic seals (ala R26B), 3D printed components for some complex geometries (coolant and oil passages for optimal distribustion, maybe even with circumeferential cooling), upstream stratified charge direct injection (like Mazda already successfully tested with great results), Mahle turbulent jet ignition to deal with the chamber shape (which is proven tech in F1 instead of the complex laser ignition they are trying to create), all aluminum housings with more meat to allow proper side exhaust port design (a compromise in overall size, but with more benifits than drawbacks)… turbos love rotary exhaust flow, but the engine itself does not like backpressure, so maybe a centrifugal supercharger (think Kawasaki H2R) instead of turbos to keep a strong linear powerband… Some 300-350 NA hp at 9000rpm, or 450-500hp with boost.
    Anyhow, this would definately increase the cost of making such an engine, but less so than would trying to hybridize the platform.
    Weight should be kept as much under 3000lbs as possible, proper double wishbone suspension, parts bin Brembo brakes, meaty tires for lots of mechanical grip, a proper 6-speed gearbox and either ATB or clutch type LSD.
    Some platform sharing might help reduce price, as long as it doesn’t increase weight or bastardizes design. I’m guessing a $50k price point is doable for an NA version.
    Sorry for that, the engineer in me got carried away haha.

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