Interesting and, as you point out, counter-intuitive. Any technical insight as to why that is? I hear about RX-7s running 15+ to get better gas mileage, so I'm really curious as to what is causing this difference in the Renesis.

The only thing I can readily think of is if the power of the car falls off a cliff near stoich, then running it slightly richer would allow you to run with less overall airflow to the point that it more than makes up for the slight amount of extra fuel per unit of air.

 

Look up one post.

 

My Post?

That really is more a driving style choice. It's like the advice for Automatic drivers to drive like they have an "egg" under the gas pedal. While with a Manual transmission you just drive at lower RPM and press the gas pedal to between half throttle and 3/4 throttle for best results. If you drive a Manual transmission car like there's an EGG under your foot you'll get the same cruddy gas mileage that everyone else gets. It's usually best MPG to drive when in the sub 2k RPM range for Piston engines but go too far and even some factory cammed engines will hesitate.

I think I see what you're saying though. The cam in the RX-8 is made for a higher RPM range, and running rich is also a safety margin for the Renesis. I really don't know anything about the Rotaries though.

 

Peak torque lambda.
You get better gas mileage when your mixture is closer to MBT than stoich.