Well designed.. Yes.
Light? Hell no.
eg. a guy swapped his rotor out for a v8, and his car gained 40kgs.
They area a very COMPACT engine, but its mostly full of metal. Whereas a larger v8 looks heavier, but its full of air comparitively.
Although Im not sure of specific weights, I have been told that rotaries are deceptively heavy. Especially if you could swap it for an alloy block engine.
I dont see why so many people harp on about rotors so much. I mean NA rotors are pretty average really.
You get bugger all power unless you port the shit out of them, and then they run like crap below 5,000rpm.
Ive seen a few dyno plots of tuned NA rotor motors, and wasnt very impressed at all.
If people spent as much money on say a 2 litre NA piston engine as they did on an NA rotor, they would probably make just as much power IMO.
Infact I bet some modern variable valve timing motors are making the same sort of power, with superior low/midrange torque.
But I would say that.
But you cant get a piston motor to go BRAP BRAP I suppose.
I think the reason they are called '1300cc' is because thats what you would think you are driving, at low RPM.
In saying that, one of my mates used to have an RX2 that was built by PAC performance in Aussie. It had big $$% off disc brakes all round, a diff out of a Mazda bongo van, and it revved to about 12,000RPM!
That was a pretty crazy car!
IMO: an original engine for a KE? A turbo charged hyabusa engine or two.