So, I know they sold the FB's in Japan with EFI 12a's. So, where are those EFI systems?

That's my long time dream. A 12a with EFI would get like 35 highway and at least another 10% power.

 

They were on the 12A Turbo.

I don't think you'd see much of a power or MPG increase I was getting 25mpg with air/fuel ratios that had my O2 sensor reading .000 volts on steady cruise.

 

So that would mean that all your available O2 was being consumed then?

 

O2 sensors work by sensing the difference between the amount if O2 in the atmosphere vs. the amount of O2 in the exhaust. They're calibrated so that when the engine is running stoich, they generate .5v. When the engine runs rich, there is no free oxygen in the exhaust and the O2 sensor generates a voltage because of the huge difference in O2 content.

I was running so lean the O2 sensor couldn't tell the difference between the atmosphere and my exhaust As long as it's not misfiring, you get killer mileage running super-lean. Rotaries are naturally lean-tolerant because of the highly turbulent conditions in the chamber. The MSD also helped a great deal

 

How did you lean her out? Timing? If timing then what is you offset? If it's the carb, how do you do that since she's sealed? I suspected my 84 always ran lean since I got 30 to 33 highway, but my emissions said no. They showed my nitrogen at .001 all the time, lowest those machines would read. And my HC's always at 60 to 80 which would indicate lean.

 

Carb tuning. Timing does not affect A/F ratio.

Actually it was a happy accident... with the '80 carb it would be dead lean under cruise and would pop back up to rich and stay there when accelerating, so I said hell, that's perfect

 

The EFI on the 12at is out of the dark ages, you need to fit a modern comuter unit.

As stock the 12at only produced about 130-135 bhp with the mpg down by 15-20%.