Can you "bore out" a wankel engine, like you could, with a like a small block chevy, in order to increase displacement? Anything else?

 

No. To increase displacement you would need to widen the rotor housing. This would require new rotors, e-shaft, seals etc. If this could be done someone would have done it by now.

 

oops, you just killed your compression and rotor sealing.

 

Sure, someone come out with 90mm rotor housings, 90mm rotors, 90mm apex seals, longer e-shaft, longer tension bolts. Those are the most important things to worry about first.

But if I remember, there are reasons not to stray from the demensions that mazda has established. Their experimental engines of the 70's didn't get far because of the oil embargo, emission constraints, and other factors, so little info is avaliable on what demesions work the best considering how thick a rotor can and should be and how large it can be since 13b and 12a used the same height demesions and are interchangable in that respect. Generally speaking, 13b's 80mm width is a more efficient width which is why they stuck with that.

 

I believe the big block engines like the 15A Mazda was developing had bigger overall dimensions...not just wider housings and rotors. Could be wrong though.

 

Don't the low compression rotors sort of increase the overall volume? Forced induction anyone?

Slap on another rotor like the 20B!

I saw a picture of a tractor with 2X 12A 's connected in serries.

What you can't do with displacement, you have to work around with cooling the intake to condense the mixture, or compress it like a turbo or SC...or both!

I suppose Nitros aids in the cooling and condensing department.