• Apr 22nd 2010 at 7:57PM
  • 35
Mazda Furai Concept – Click above for high-res image gallery

It's the rumor that just refuses to die. We're not sure if that means there's a lot of truth behind it or it's just wishful thinking, but once again we're hearing that Mazda is hard at work on a new RX-7 sportscar. And while you might think such a vehicle would be as easy as adding a turbocharger to the existing Renesis-powered RX-8 and jettisoning the back seat (or pulling a Kabura with the MX-5's platform), Mazda apparently has much more grandiose intentions for its next range-topping sportscar.

According to Motor Trend, Mazda's oft-talked-about 16X rotary engine is now capable of running on either gasoline or diesel with nary a difference in performance. We have to wonder about the accuracy of such claims, but if true, perhaps running on diesel or biofuels would give Mazda the eco-cred it's aiming for – specifically boosted fuel economy and lower CO2 output. In any case, MT says that Mazda is aiming for something north of 300 horsepower with improved fuel consumption, emissions and oil intake over the current Renesis.

As ever, we're taking a wait-and-see approach to these continuing rumors. As much as we'd love to see a new RX on the scene, we're beginning to wonder if it's ever going to happen. In the meantime, enjoy the photo gallery of the too-awesome-for-words Mazda Furai concept.

[Source: Motor Trend]

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    • 1 Second Ago
      • 5 Years Ago
      Nary a difference in performance and perhaps nary a difference in fuel consumption. Part of the advantage in Diesel engines is that the compression ratio is higher. The mazda rotaries have pretty low compression in the first place, no?
        • 5 Years Ago
        Actually rotaries have huge compression ratios to the point where it's a problem because they can squish the combusting gas until it puts the flame out.
      • 5 Years Ago
      If the rotary can switch between hydrogen fuel cells and regular gasoline (look up their RX8 hydrogen fuel cell prototype), I don't see why it couldn't switch between gasoline and diesel. Only thing I'm not sure of about that particular prototype (RX8 hydrogen fuel cell prototype) is if there are any differences in power when switching between the two.

      I'm still rather skeptical about gas mileage though... rotaries haven't been known to be fuel efficient.
        • 5 Years Ago
        • 5 Years Ago
        Burning hydrogen or natural gas in a gasoline engine isn't a hard conversion.... getting a gasoline engine (with a normal compression ratio) to burn diesel is a completely different beast. Unless something has changed, a rotary engine is still made up of triangular rotors spinning in a trichoidal chamber. The orbit on the whip shaft is fixed, so unless the housing can change shape on the fly, there's no way to get variable compression ratios out of a rotary.
        • 5 Years Ago
        Ooops double post.

        @ Chris O


        I guess it all depends on the compression ratio.
      • 5 Years Ago
      I love those wheels on the Furai!
      • 5 Years Ago
      When I shoot SCCA races, I am no more that about 20 meters from the track, 60 meters at the most. At 60 meters using a 400 mm or 600 mm lens is just good enough. I prefer using the Nikkor 200-400 mm zoom when shooting sports cars however.
      • 5 Years Ago
      The new RX-7 will be in Forza.
        • 5 Years Ago
        Oh wait.. it probably will be..
      • 5 Years Ago
      Why do they not just build a mid-engined sports car, piston or rotary engine choice... that looks like a production Furai?

      That would be thoroughly amazing.

      More mid engined performance. There are already tons of forward mounted engine options. :D
        • 5 Years Ago
        I've been dying for a car producer to make a (at least semi-affordable) rear-mid engine sporty car for the masses. Snooping around ebay motors for 2nd gen MR2 turbos isn't really cutting it for me. I just love that weight distribution and the funny looks you get when you open the hood and throw a bag in...

        Seems like for cost and marketing reasons it's probably not going to be likely. A man can dream though.
      • 5 Years Ago
      F the new rx-7. build that damn concept, charge GT-R money and make every car nut on earth stand and take notice.
        • 5 Years Ago
        Same body as the old rx-7? If so, ditto :)
        • 5 Years Ago
        same body, updated lights, and a new engine; and I'll be quite happy ;)
        • 5 Years Ago
        That would be awesome, though I'm not sure Mazda has the volume to put it into production.

        Still, if a new, true, proper RX-7 ever reappears, that'd be really cool.

        I still don't get why Mazda doesn't push the rotary more, especially into things like the Miata which are a natural fit.
      • 5 Years Ago
      Well they better do something quick because the RX-8 needed a replacement 2 years ago. I'm wondering how much longer they'll even bother sending them over here for.

      I'm all for a kabura like 4 seater on the miata platform though.
        • 5 Years Ago
        How about a Kabura with an 6 cylinder ecoboost engine? The 3 seater is just perfect!
      • 5 Years Ago
      The Furai concept is gorgeous... it's a pity that any production RX-7 won't look a thing like it.

      I hadn't heard about the supposed diesel/gas dual capability. It doesn't seem likely, given that a rotary isn't a variable compression engine (or a turbine, for that matter).
      I would think that, at the very least, the fueling system, emission controls, and engine internals would have to be different.

      Does anyone know anything about this?
        • 5 Years Ago
        Partially replying to your original comment as well as your last one:

        I don't imagine the engine has a particularly crazy fuel or ignition system of any kind. Back in the 90s, Mazda had already found out they could run the rotary on a stratified charge and thus needed no throttle plate like a diesel. So I'm not surprised this came about. Also, rotaries have notoriously high compression ratios so, again, I'm not surprised to find out they got it to work with diesel.

        What is surprising is that generally the wankel's weak point is the apex seals, they must be a new design for this to work. In the past they've been fragile and can only take so much pressure. So how many pieces the seals are, what material they are, and the effects on both their robustness and ability to seal at high and low speed and temperature must have been greatly improved/altered.

        Finally, there is one other way to get variable compression out of a wankel: longer apex seals and a smaller rotor. You could rig an actuator on the ring gear the rotor spins on and alter its orbit without hitting the housing. The big problem is again apex seals as they would be under much more stress.
        • 5 Years Ago
        There is a lot of press supposition on the Mazda rotary subject. Variable engine fuel is one, for instance diesel/gas. Here are some recent comments and there are more based on comments about comments from other comments. Whatever Mazda does won't be minor....they have been testing a hydrogen fueled RX8 in in the Scandinavian countries for some time now. Norway is a leader in hydrogen fuel power they have been working with it for many years. One of their new projects uses solar powered fuel stations to separate hydrogen out of water in self sustaining fueling stations. The US lags in nearly all practical research in these areas. The government sponsored research here never seems to make it out of the university setting.




        • 5 Years Ago
        I'm really excited about the new RX7 now. I agree SS, whatever it is will be major, but I was thinking major performance, not major technology. I didn't really understand the hydrogen push. Sure a lot of automakers have played with the idea, but unlike hybrids (shudder) no hydros have made it to market and the US doesn't have the infrastructure. The more I think about it the more it makes sense tho.

        If hybrids and EVs can come to market forcing you to lease batteries or buy and install chargers at your home for another fee on top of the cost of the vehicle, I wonder if Mazda could do the same with a hydrogen generator for a dual fuel rotary. I'd be willing to pay a hybrid-like $30-40K for a non-electric 30 mpg hybrid RX that maintained the performance and weight of an ICE car. Run hydrogen 6 days a week and gas on Saturdays?

        Honestly, I'd resigned to just keeping my FCs and Zenki SE3P forever. I didn't like the Kouki enough to upgrade and while I know the 16x will be nice, I doubted the next RX would haul my kids like the 8, but if they take it that far, I'll be one of the first to put my name down.

      • 5 Years Ago
      It wont be the same....

      Just leave the 7 alone and move on.
      • 5 Years Ago
      Let's hope this car beats the 22mpg hwy the current one gets..
      How the hell do they plan on making CAFE numbers out here in the USA?
      Direct injection can only go so far. Should help the low end torque out though..
        • 5 Years Ago
        That's surprising. i wonder why they rated it at 22mpg hwy?

        I get 32-34mpg hwy in my car on long runs too ( it's rated at 26 ), but regular mixed city/hwy driving is just barely above EPA... i'm sure your car is the same.
        • 5 Years Ago
        this is a cut and paste from a window sticker from a 2010 GT automatic..... read all the fine print.

        Fuel Information

        16.0 23.0

        Estimated Annual Fuel Cost: $2209.0

        Actual Mileage will vary with options, driving conditions, driving habits and vehicle's condition. Results reported to EPA indicate that the majority of vehicles with these estimates will achieve between 13 and 19 mpg in the city, and between 19 and 27 mpg on the highway.

        For Comparison Shopping, all vehicles classified as SUBCOMPACT CAR have been issued mileage ratings ranging from 12 to 32 mpg city and 12 to 32 mpg highway.
      • 5 Years Ago
      It isn't as though you can switch between regular and diesel gas on the fly though; you'd need two tanks for the different fuels. I'm assuming it just means they (Mazda) have the choice of making it gasoline or diesel for production, right?
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