The 3rd gen RX-7 engine is one of the most complex turbocharged engines ever in production. I have never seen a Z w/ one of them in it. I think that it would be a foolish swap considering it's complexity and expense. You can build an L28 with just as much hp and a whole lot more torque for what it would cost for a 13BREW swap. The 13BREW is rated at 255 hp and 215lb/ft of torque. It's pretty easy to make 215 lb/ft of torque from an L28. That is what makes acceleration.
As far as a lighter engine in the Z, I knew of an autocross Z that had an L20B that was built by Robello. The car weighed only 1850lbs. Believe me, it was quite competetive.
Ian
> Has anyone experimented with a swap to a
> rotary engine out of a 3rd generation RX-7?
> I love that sequential turbo engine in the
> RX-7, and would love to have an engine that
> light in my Z. I've seen them swapped into
> 510's, but has anyone seen one swapped into
> an early Z?