Well its only fast because it was the equivalent of labeling a v8 as a v6. Under that pretense when you have v6 expectations of course it'll be fast.
However rotaries are known for being rudely inefficient.
I and a few rotary enthusiasts consider a 13b as a 3.9L v6 essentially. Has what is arguably six combustion chambers each at ~650cc.
What its actual displacement is, is amd always will be disputed among fans.
Mazda only utilized 1.3 for insurance purposes and racing bodies recognize it as a 2.6 for some bizarre reason.
Just to show you why they perform so well in competition.