2nd Sep 2001, 00:27

This is what I'm guessing... here in Australia rotary engines are classified as double piston motors therefore a 12a = 2.4 or a 13 = 2.6

You get it?

20th Sep 2001, 12:26

Who cares about the number of pistons your car has as long as it hauls ass. What's a top speed for one of these, all souped up? I topped out at 158 mph. Can I go faster?

20th Sep 2001, 20:37

C'mon, don't make Aussies sound stupid!

In Australia, as everywhere else, they are simply classed as a Rotary Engine. All this means is that to classify them for any form of motorsport you multiply their cubic capacity by 1.8. All 13b engines (like the one that has been fitted in all Aussie RX-7's since 1984) is a 1300 cc engine as the capacity of each of the two combustion chambers totals approx 630 cc.

Using the multiplication factor of 1.8 against the capacity of a 13b will give you 2340 cc, which is close enough to 2.4 litres.

But that is only for motorsport... they are still a 1300 cc engine.

27th Jan 2002, 13:29

OK, let me put this to rest. EVERY RX-7 that carries a 13B rotary engine displaces 1.3 liters, or 1308 cc's. The only rotary engine that was 2.6 liters was the 1991 Le Mans winner 787B race car. The 26B, 4 rotor engine in it could never be used in a production car because of gas mileage, size, and extreme performance. There is no such thing as (1.3 + 1.3 = 2.6), that's just stupid. Also, as far as pistons vs. rotors... The reason that Mazda still carries the Rotary is not because they're too proud to drop it, its because they were the only ones to keep faith in it. If it weren't for the 1970's gas crisis, then most cars would probably carry rotaries. GM, Ford, Chrysler, Nissan, Toyota, and many other companies were experimenting with Rotaries before the gas crisis hit, then they axed them after the money got tight and found that rotaries were not as gas efficient. You can down on efficiency and gas milage all you want, but once you hear the high pitched buzz and a flash go by you that says "RX-7" on the back, we'll see who's laughing then.

8th Oct 2002, 02:36

There is a 20b which came in a cosmo and is a 2.0 rotary.

27th Sep 2003, 03:01

Come on guys, stop it already. the 13b is 1.3 liters!

3rd Oct 2003, 08:49

What do you folks say about the Renesis, enough HP without turbocharging. Seems like Mazda solved another reliability problem of its rotary engines.

30th Jun 2005, 23:06

I am an RX-7 lover I have a dream to own one someday. I was wondering what I should expect to pay for one and what kind of preformance to look for.

31st May 2006, 19:53

The RX7 has two rotors, each with three faces. There are three combustion cycles per rotation, one for each face. Each rotor ALL UP has 654cc. The 13b has a 1308 capacity. Easy enough I thought (any questions just go to howstuffworks.com).

Hope that helps!

24th Sep 2010, 13:54

Have to fix a few COMMON errors here...

The RX7 1992 onwards (series 6 -8 FD3S - which is ALL of them from 1992) were twin sequential turbo, twin rotor engines. 13B Engines.

People get confused on ACTUAL engine SIZE and what they think it should be calculated at..

As said, they are 654 cc displacement per rotor housing, and there are two rotors.

So if you simply add the two together you 1308cc total displacement = 1.3 Litres.

The reason they class them in some motorsports and counties as twice the swept volume = 2.6 Litres is because it makes it fairer for the piston people...


That is why you get a standard 1.3 Litre Turbo Rotary producing a very reliable (Yes they are reliable these days) 274HP and 357Nm torque since 1992 (18 years ago).

And if you want to compare a standard 20B (3 rotor = 2.0 Litre) for its time, it produced 307Hp & 407Nm torque way back in 1987! (23 years ago)

Oh and let's not go to the 2.6 litre quad rotor in Le Mans that was built in 1991 that WON Le Mans that had 700Hp :)

Oh, and I know hydrogen engines take more energy to produce the hydrogen than they put out, so are completely useless right now, but because of the rotaries set up, it is actually miles ahead of the piston engines, due to design and the way the seals are lubricated and no valves :)

Thank you for your time :)

P.S. I like V8's too!!!