read the current sport compact car issue.. very interesting article on how mazda is wrong in claiming its a 2-stroke 1.3L rotary when in fact its a 4-stroke 2.6L... :ghey: :chuckles:

 

Um, any more detail?

 

i couldnt get the article online... its in the current scc with the tokyo racing on the cover... my buddy who was telling me about this is bringing the mag in after lunch so i can read it..

 

its a 1.3.

each rotor is 649 cc as i recall (could be a little off) and there are two rotors

 

The physical displacement of the motor is 1.3 liters. The nature of the rotary motor is that it has two power pulses per rotor per revolution of the eccentric shaft (its equivalent of a crankshaft). So yes it is more efficient than a piston motor given its displacement, but it does not displace 2.6 liters.

 

Kinda off-topic, but how come the automatic RX-8 makes more torque at a lower rpm than the manual version?

Engine Specifications


1.3L 210 hp Rotary 1.3L 250 hp Rotary



Horsepower 210 @ 7200 RPM 250 @ 8500 RPM


Torque (lb-ft) 164 @ 5000 RPM 159 @ 5500 RPM


Displacement (cc) 1308 1308

 

"First things first. the new renesis engine in the rx8 is a 2.6L. the older versions of the 13b were 2.6L to. the 12A in the 1st gen rx7 was a 2.3L and the three-rotor 20b is a monstrous 3.9l. if you've been told a 13b was 1.3l, you've been lied to.

"on a four stroke there's only one intake stroke for every two revolutions, so from a breathing standpoint, displacement is how much combustion chamber volume gets sucked in over two revolutions. for a rotary, with one intake stroke per revolution, that means measuring two combustion chambers per rotor, not one, like mazda says. each chamber in a 13b displaces 654cc, so by mazda's two-stroke method, a 13b is 1308cc. by my four stroke, its a 2616cc"

 

I think what they are trying to get at is that it's piston-equivelant would be 2.6L because of the two power-strokes per cycle as opposed to a traditional engine...

 

Because the automatic transmission model is limited to 7500 RPM. The 6-speed peaks past 7500 RPM, so Mazda tuned the automatic version to peak before the limiter kicks in.
This is not a new argument.

The displacement is still 1.3 liters because the combustion event occurs in the same location every time. The fact that there are "two separate chambers" does not change the fact that there is only one combustion chamber per rotor housing at any given moment, and it only exists at one point in space.

If it was really 2.6 liters, then Mazda would call it 2.6 liters.

 

Hmm, I meant to say is, how come the auto version of the RX-8 has more torque than the 6-speed manual overall?