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A-12 and a B13?

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  • A-12 and a B13?

    so i was talking to my dad while hes playing his videogames and suddenly he goes WHOA!! its a RX-3!! i look at the screen and say wth... then he tells me yeah a rx-3 he said something about an A12 and a B13 i wana know a few things...

    1] whats the difference between the A12 and the B13 engine..
    2]what the 2 engines have//dont have that make it so different
    3]if theres any other kind of rotary engine i should know about
    4]what in the world is a RX-3

  • #2
    im not a rotary expert but generally speaking

    1) a12 is an early version of the rotary engine, b13 is a later model.

    2)not sure... someone must know, something to do with the rotars?

    3)renisis the newest version of the rotary, as found in the rx8 B20 3 rotar engine. probably the most sought after model

    4) an early model in the RX series. if i am not mistaken RX stands for rotary experimental. they didntt start the series right at 7 :P


    • #3
      So are there like concepts or race cars from back in the day by mazda called rx1, 2, 4, 5, 6


      • #4
        "12" mean 1.2 liters, where 13 means 1.3 liters.

        Other diffences are the 12a uses a carb, where the 13b uses EFI instead.

        The Rx8 Uses another form of the 13b known as the renesis. But its a 2 rotor engine, not a 3 rotor. to be blunt it has larger ports and everything is computer controlled- its mazdas attempt to re-introduce the rotary to public as a "problem free" engine, one thats free of the reliability problems which the general public has in mind with the Rx7 series of cars. They make about 240 hp NA.

        The 20b is from the japanese Mazda Cosmo. Its a 2 liter rotary engine using 3 rotors, instead of just 2. they make about 280 horsepower on twin turbo set up, you remove those turbos they make 250 or so na hp. They use very little boost- youll notice a lot of japanese cars will limit themself to around 280 hp. You can easily port these engine and run around 300-350 NA hp, or you can go the turbo road and easily hit 5-600 hp.

        The Rx3 is a early rotary sports car. Now they dont exactly have Rx1-8, but they do have about 8 generations of vehicles that have used the rotary engine. The cosmo is one (counted in the 8 models), hell they even have a rotary powered truck from the 70s.
        Last edited by SidewaysGts; 12-16-2004, 08:35 PM.


        • #5
          Mazda also made a 4 rotor race engine. It was put in the 787B race car and won the won the 1991 24 Hours of Le Mans. It is the only rotary-powered car and the only Japanese car to ever do this. It has about 2.6 liters with an output of 700hp and 620lb-ft of torque. To my knowledge, it is the only mid-engined Mazda rotor car.


          • #6
            26b, awesome engine. Naturaly aspirated, has a telescopic intake manifold, awesome stuff.


            • #7
              [QUOTE]Originally posted by SidewaysGts
              [B]"12" mean 1.2 liters, where 13 means 1.3 liters.

              Other diffences are the 12a uses a carb, where the 13b uses EFI instead.[QUOTE/]

              the 12a was 1.1 liters. Pending on the series the rx-3 had either a 10a or a 12a. There is the 12at which is efi. but that goes in the first gen rx-7.


              • #8
                most engines are slightly less then what they are advertised as, companies often round up for simplicity.

                the 4age is a 1.6 liter engine but its realy like 1.5xxx

                Added: Just a quick question; i thought all the 1st gen rx7s used carbs? got any pics of them with efi or some place with info on them?
                Last edited by SidewaysGts; 12-16-2004, 11:51 PM.


                • #9
                  well the 12at was exclusive to Japan (U.S. sucks once again) but all american rx-7s 79-83 were 12a carb, where as the 84-85 GSL-SE had a fuel injected 6-port 13b similar to the S4 n/a FCs but had thicker apex seals, and heavier rotors compared to the newer n/a versions.
                  Last edited by theflatlander; 12-17-2004, 05:39 AM.


                  • #10
                    Originally posted by SidewaysGts
                    has a telescopic intake manifold [/B]
                    Can you explain to me what a telescopic intake manifold is?


                    • #11
                      Fairly self explanitory, the manifold "tubes" extend and contract as needed. I dont know the exact specifics, just the general idea- so maybe someone can go a little further into the detail behind them? I must admit its a pretty awesome idea and worked quit nicely (as shown by the vehicles impressive na hp)

                      Heres two pics i found so you can see what it looks like- this is the 26b used in the 787b.

                      Fully extended


                      Added: Found some info on it ill copy/paste

                      For induction, the engine employs peripheral ports for good volumetric efficiency, with a sliding throttle value used for low restriction in wide-open throttle (WOT) operation. Another feature is the telescopic intake manifold system (TIMS), the first of its kind over used on a racing engine.

                      It is a well known fact that the dynamic effect of intake airflow can be used to increase volumetric efficiency. The system adopted by Mazda employs telescopically-variable intake pipes, where the length of the pipes varies steplessly to match the engine speed, thus providing a dynamic effect over a wider engine speed range.

                      The telescopic intake manifold system, schematically shown in Fig. 9, consists of cylindrical pipes inside which air funnels can slide. The length of the four intake pipes is controlled by varying the position of the air funnels. The sliding air funnels are as thin-walled as possible, and there are no protrusions in the air passages so as to minimise chances in airflow.

                      The sliding air funnels for No.1 and No.2 rotors are interconnected via a linear ball bearing, as are those for rotors No.3 and No.4. The linear ball bearing is arranged such that it slides along a guide projecting from the stationary pipe side, thus positions the air funnels in their appropriate locations.
                      Last edited by SidewaysGts; 12-20-2004, 02:32 AM.