I just found this article in Ward's Auto World (Mar 1, 2002) stating that the Renesis rotor is 14% lighter - that would make the Renesis rotor 8.2 lbs, not the 8.7 that I stated earlier.

"Design innovations made it possible to eliminate the twin turbochargers employed by the current 13B rotary engine. By moving the exhaust ports from the trochoidal housing to the side housing of the rotor chamber, the overlap between the exhaust and intake port openings was eliminated — a crucial emissions and power-generating factor. Meanwhile, reducing rotor weight contributes to higher output of about 250 hp and torque of 159 lb.-ft. (216 Nm) — figures that are roughly equivalent to the 280 hp and 152 lb.-ft. (206 Nm) of the twin-turbo 13B in the existing RX-7 still sold in Japan. Rotor weight was trimmed by 14%."

Ken Powell
Bryant, Arkansas
501-847-4721