I had an idea the other day. The RX8 computer keeps the engine
    at stoichiometric mixture ratio at all times according to the OBD II
    data
    I have captured so far on my RX8. Even under full throttle.
    Stoichiometric
    is 14.7:1 to one as I recall so that is not the best for best power.
    Best power happens at 12.5:1. Cheap way around this is to
    fool the stock computer into thinking it is getting more air than it
    really is.
    Consequently it will put out more fuel richening the mixture.

    The idea is you program a $50 PICAXE computer to take data in from
    the mass airflow
    sensor and the throttle position sensor and modify the mass air flow
    data going
    to the stock computer when the throttle is wide open. This device
    could be installed by disconnecting the mass air flow sensor and the
    throttle position sensor and plugging them into the PICAXE. Two cables
    coming out of the PICAXE could then be plugged back into the
    sensors. This way
    the standard RX8 engine configuration can be easily and quickly
    restored by doing the
    install in reverse.

    On the other hand when the throttle is partially open during highway
    cruise
    you could lean the mixture to get better MPG. The rotary will run at
    mixture ratios
    of up to 17:1 or higher at steady speed low load freeway travel. I
    don't know exactly
    what this will do to the catalysts so do this at your own risk.

    --
    Paul Lamar ...No rotor no motor.

Hi Paul,

    Sorry, but at full throttle/high rpm - or any time you are off
closed loop - the mixture is not 14.7.  Stock typical ratio at high rpm
is ~11:1 to 13:1, sometimes less.  Even in closed loop, the target
mixture is mapped and varies up and down from stoic.  We tried hard and
could not improve the mix in feedback from stock.  Above that, we did
make some improvement (~5% max), and that is what we deliver in the
reflash service we now offer.

Jim Mederer

Ops you are right. I forgot I took this acceleration run in 2004. I was wrong.
Here is a screen capture. Yep Lambda goes rich.  I was looking at a lot of
steady speed data.

BTW note how much higher temperature the intake system is than ambient
air temp. Looks like it needs some insulation.

Well then only half of my half ass idea will work. The lean part. I have never seen
Lambda go much over 1.02 on the RX8 which is about 15:1. I have seen it
go well over 15:1 on the Honda Odyssey. I think you could lean
it on the freeway to 17:1 or 18:1.

Most of this data is for a piston engine
but we have found the rotary will run much leaner. A lot of our guys are cruising
their engines at 17:1 or higher.  My guess is.... it is
naturally stratified charge due to the rotating combustion chamber.

Of course it will never be as good as a turbo compound rotary.

The advantage of the PICAXE over the reflash is it can be reinstalled cheaply and quickly.

Paul Lamar ...No rotor no motor.

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