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The Rotary Engine

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  • The Rotary Engine

    What do you guys think of the Wankel rotary engine and its potential in consumer automobiles and racing?

    The Mazda 787B proved without a doubt that rotary engines can hang with the best of them.

    I wish companies would devote more R&D to them, they seem like such an untapped source of power for vehicles. Yes they have glaring flaws but so do piston engines. If enough money is devoted to researching and developing rotary engines they could be a very good source of power for cars, maybe even motorcycles (due to their excellent volume/power ratio).

  • #2
    i think mazda has a patent on it, which is why only they make it. I hope they make a new rotary sports car.

    the 2nd gen rx-7 is the best car ever imo, followed by the fd, and 1st gen sa22.
    rx8 was not bad but more of a semi sports car, and a little too bulky for my taste.

    I wonder if it'll make a good non sports car from a commercial standpoint. it is good in terms of reliability, and weight/power ratio, if it's got a reasonable cooler and not super powered like the sports cars. but the extra cost in gas maybe a problem.
    It'll be interesting how the hydro rotary cars end up.


    • #3
      Mazda only holds patents with it's old 13B-REW and 13B-DEI. There are no patents on the 13B-MSP Renesis other than the 40 year old patent on the porting and mounting of the engine inside the RX-8.

      I might mention that Mazda has stopped production of the rotary due to declining sales.

      So no other manufacturer can make a rotary with a twin sequential turbo system.
      Last edited by Diminished Dream; 12-07-2011, 01:38 AM.


      • #4
        sports cars in general has declined in sales and never been that good in terms of marketing. higher production cost and maintanance for high performance, doesnt go hand in hand with non enthusiasts and rising gas prices.

        the fact that a lot of enthusiasts also prefer older models, and will hold on to them, while the average person just buys whats new when their car breaks down doesnt help sales.

        atleast it's still not too hard to get a 2nd hand fc or fd at the moment. assuming you got enough $$$ to afford and maintain 1.

        the only problem i see with the rotary engine is that it over heats easier than pistons, and burn gas faster. For reliability, power-weight, space to work with, etc it's got piston engines beat. So I do wonder if it'll be successful(marketing) if they decide to release a non sports car the right way.
        Last edited by chimukun; 12-25-2011, 02:09 AM.


        • #5
          There are a few problems with rotary engines that prevent the automotive industry from putting a lot of effort into them.

          First and foremost, rotary engines tend to run hot, especially when you try to make them fuel efficient, and that means more NOx emissions. With emissions regulations what they are, on top of an over-the-top catalytic converter and rather docile spark timing, the RX-8 had to run quite rich in order to compensate for that.

          Second, one of the main advantages of the wankel, it's displacement-to-power ratio, doesn't earn it many points in the automotive arena, due to it's efficiency/emissions problems. It also requires a more comprehensive emission control system, which somewhat nullifies weight advantages.

          All that said, the wankel does have potential applications, particularly small propeller planes. The emissions requirements are notably less stringent, and the high engine speeds are far more useful. Plus, the size and weight constraints are far more stringent in aircraft. That's where most future wankel research will be. So, if you're looking for a good place to scope out a kickass project, look at dropping an aviation wankel in a car. Just don't expect it to pass emissions.


          • #6
            i think the rotary engine would be a nice charging unit to electrical cars. Just when the battery is low, kick in the rotary engine to charge the batteries.


            • #7
              electric engines suck. no matter how much they improve it I'll stick to gas, unless they make it handle like a manual gas car with clutch, and got the engine roar.


              • #8
                main reason it'll probably never make it big again(the rotary engine), is emissions. the're too fuel heavy and their power output is considerably lower than most engines(if you calculate displacement as they did before they banned it from most racing). when/if the 16X is perfected, and they hybrid it, giving it the torque it needs down low, and being more fuel efficient than the 13b, we MIGHT see another rotary for another 5 years. but nothing beyond that.


                • #9
                  cool concept but it'll never catch on.


                  • #10
                    ^ Cool concept? It's been in production since 1965 (from Mazda). The RX series was one of the most amazing sports car families on the market. For quite a long time, the 92-02 RX-7 was regarded as one of the best sports cars on the planet. It's not a concept.

                    Reliability is a big misconception with rotaries. They're actually just as, if not more, reliable than reciprocating engines. Yes, they require a small amount of oil every now and then to maintain the apex seals, but it's not that much and barely costs anything.

                    Power output is superior in comparison with engines of the same size as the typical 1.3L present in most RX-7s. A standard non-turbo 13b produces around 145hp. A 1.3L 4-stroke reciprocating engine produces around 80hp (there aren't many 1.3L engines out there). In most cases, a "proper" comparison would require a reciprocating engine with roughly twice the displacement (that is, a 2.6L).

                    The reason it keeps getting shafted is because the RENESIS engine never got the power it needed, and rising gas prices (the engine's inherent weakness has always been fuel economy). It only had 197hp off the showroom floor in it's initial form, and never got a factory turbo option that owners and rotary enthusiasts constantly asked for. A simple turbo kit was able to boost it up to 360hp quite easily, but nobody seemed to notice.

                    The 16X is still in development, and looks promising if Mazda's figures are indeed factual. The rotary engine is a smooth, wonderful engine with amazing potential.


                    • #11
                      Originally posted by Tessou View Post
                      ^ Cool concept? It's been in production since 1965 (from Mazda)..... It's not a concept.....

                      Reliability is a big misconception with rotaries.....
                      Concept - yes. Just because ONE automotive company has been using it in ONE line-up of vehicles does not mean it's NOT a concept. It is a concept and has not been replicated or improved upon for various reasons, some having already been mentioned.

                      As for reliability, you are correct, it is just as reliable as say... the engine in a DSM (Eagle Talon/Mitsubishi Eclipse). They are good engines if you do not over-rev them. Unlike conventional engines, once you do that, you're 'hooped' so to speak. Not only that but then you need to track down someone who is trained in rotary engines.

                      Remember kids: Just because you are awesome at MW2 on the PC doesn't mean you're going to rock it out on the Xbox... same idea here. Mechanics (the vast VAST majority) have no idea how to properly repair a rotary engine. That is an issue that several friends of mine in two cities in Canada had - Saskatoon & Calgary. Oh, and feel free to offer a mild rebuttal about how 'tiny' and 'uneducated' those cities are, I'm actually kind of hoping someone will. The fact is that rotary engines are NOT the same as a standard piston engine, and as such, require a specially trained person to repair them.


                      • #12
                        Audi is using a rotary engine for a little car to putter around town.



                        • #13
                          I've owned the RX7 FD3s and a RX8. I am also a spare time mechanic, I own a garage with a lift in it, a commercial compressor and all the appropriate tools to repair cars.

                          The RX7 was a good car, i'd say maybe a bit mean of a suspension. I would have to disagree with Tessou tho. Quite unreliable, I live 5 minutes from the mazda dealerships and my small town has about 15-20 RX8s in it and i've seen 3 RX8 go in that garage with smoke pouring out of every orifice the car had.

                          I live in Quebec so its quite a bit cold it had a hard time starting in the winter, as well as weird mechanical glitches. The interior was complete garbage, bunch of switches died, the ash tray cover was broken when i got it, as well as the middle console. The climate unit died twice, as well as the stereo. The steering rack went bonkers and would jerk the wheel, had to have it replaced. It wasn't quite powerful and costed me a fortune in gas. Mine was a 2004, and my 2003 350z, which is a car in a similar price range, never had 1 thing break on it, the only thing i've ever replaced was the oil and the brake pads/rotors.

                          As far as the RX7 was concerned, it was a JDM import with a RHD, It ran good for 1 month total, the turbos started to leak oil and had to be both replaced, as well as the radiator and the cluster (because of a bad ground), which they are known for. It was a decent car but my wife only got to drive it for about 3 months in total on two years of having owned it.

                          Replaced the RX7 with an Acura NSX and the RX8 with a Nissan Murano LE, and never changed a part on both of those, except for the Clutch on the NSX and the oil pan seal.

                          I've owned many Nissans which almost never game me trouble
                          Nissan 180sx 1994 - RHD
                          Nissan Skyline 1989 - RHD
                          Nissan Skyline 1991 - RHD

                          Even my Pontiac Firebird 1990 gave me less issues than mazdas. I've owned also a Mazda Protege 2003, brand new which rusted at the speed of lightning and I had to replace the rotors, pads, calipers after 15000 kms.

                          Needless to say, ill never own another mazda. While the rotary engine isn't a bad concept, its only applications are racing, it lack torque, is unreliable and takes way too much gas. Therefore is good in a setting with high maintenance, can be boosted, and doesn't care about gas.

                          On a side note, I have an RX7 FD3S Engine crated and ready to go if anyone wants it, with the transmission still attached and 2 brand new turbos

                          That is my opinion on them, Possibly I just had bad luck with them, or possibly it is a bad concept.