For Rob or anyone who knows MAZDA Rotary

Yep - typically rotary kind of attribute. Apparently the Auto is tuned for more torque (as per your note). I drove an RX-8 6-speed at the weekend (thought I might get one as a day to day car) and i really liked it, obviously not much torque but if you like the revvy nature of a 360, then an RX-8 has that appealing red line. The dash is great - not a bad buy for 30K!

 

What you are seeing is a combination of things:

1) The wankle engine has taken a thermodynamic process of a 4 stroke engine and compressed the 4 strokes into a single rotation. In effect, this makes the engine have HP numbers more like a 2-stroke engine than like a 4-stroke engine of the same displacement.

2) Without the reciprocation of pistons and valves, there is little power consumed in simply rotating the engine over and over. Heck the valve train basically doesn't move! (*) Then it is half the size of a reciprocating engine of similar power levels, so it has the rotational inertia of a very small engine.

3) the only drawbacks of the wankle are: A) large piston surface area make emissions harder than piston engines, B) the seal between the sides of the piston and the chamber wall adds friction, C) the intake and exhaust ports are timed by rotation and can't be altered easily (like changing the cams), D) compact design makes it hard to adequately cool the internals in high output conditions.

(*) the vavle train moves by changing port size to match the flow characterietics of the intake ports to the rotating piston. The valve train does not open and close like a reciprocating engine valve train moves.

 

Hi all,we use'd to service a couple of rx7 turbo 2's,yep they will rev up a treat
just the cornering ability was somthing to be desired NOT,
Im sure mazda's rx8 is now much better from what ive read,havent had the chance to drive one yet,

Dale.

 

Hi Rob,bit of a story on the engine side Rob,one of our cutomers who had a 7 turbo 2 filled up with petrol went to pay came out would'nt start,got it feched in totaly locked up,we couldnt belive it the rotor had just split in half,
how wierd is that drove on for gas went to pay split rotor no go,we dont do rotory engines so the job was done by somone else,nice engine though love the high rpm,

Dale.

 

I'm a self confessed rotorhead and have owned a 3rd gen twin turbo RX-7 in the recent past (I'm still looking for an elusive Series V 2nd gen GTUs). The natural simplicity of the Wankel designed rotary engine is much of the reason why it's so smooth and "free spinning" as you experienced. In a basic 2 rotor engine there are essentially only 3 moving parts (2 rotors and the eccentric shaft) and as they're going in an elliptical motion the vibrations caused by the up & down motion of the reciprocating piston engine aren't really there. I suppose technically a rotary engine, if designed properly and strong enough, could rev almost unlimited. There are some single rotor industrial applications that if I recall correctly can run upwards of 30,000rpms. Even a monster ported, bridge ported, or peripheral ported 12A or 13B (which some Spec 7 run) can turn upwards of 10,000rpm. The downside to this major port work though is that there is a drastic decrease in torque & reliability. From my limited understanding of the RENESIS (I just haven't been reading up on it as much as I would like to due to time constraints) is that its more or less like a peripheral ported rotary, but it's hard to relate the two as the rotor housings in the RENESIS are of a new design and not quite like the "old" rotary design although not entirey dissimilar either (um, if that makes any sense ) I'm just hoping Mazda, if they decide to continue developing the RENESIS, brings back a 3 rotor version of the engine such as they had in the JC Cosmo's or at least slap a turbo or supercharger on the current 2 rotor RENESIS. Multi-rotor (erm, well more than 2 rotors that is) engines are really gaining big popularity in places like Australia so hopefully Mazda will get the hint that people like big horsepower AND torque. Just as long as they work the bugs out of the system and train their mechanics before unleashing a complicated sports car on the public like the did with the 3rd gen RX-7.

 

I remember one of the car magazines last year had artist renditions of the next gen RX-7 due out in Japan in 2006. It looked awesome. Nothing like the Rx-8.

Rob, that was an awesome website. I never understood how those things worked.