George I think you are right. With the bell mouths the runners are 15.75
    inches long. We will be running on an un instrumented test stand
    first, so
    this is our first attempt. If we can get @200hp out of our RX-8
    engine, we
    will be delighted. Heck, we do not know if the engine will even run yet,
    lots of work ahead of us. Milo

    15.75 inches is too short for 6500 to 7000 RPM Milo.
    What you need is 25 to 28 inches.

    I don't think you will see anything near 200 HP at 6500 to 7000 RPM.

    However if you want to test it on a dyno the Mazdatrix dyno is
    set up for rotaries. You just bolt them in and run them.

    As far as I know the Mazdatrix and the Racing Beat dyno are the only
    ones set up for rotary engines in the US. Most other rotary shops use
    chassis dyno's. I could be wrong but I have yet to hear of one.
    If anybody knows of other engine dynos set up for rotaries please let
    me know and I will pass the info on the next time the subject comes up.
    Power Sport had one but I don't know what happened to it.

    Paul Lamar ...No rotor no motor.



    Milo,

    Nice work on that RX8 engine. Hope it runs well for you.

    About the horsepower, I just ran a few figures throgh my Turbochart
    spreadsheet. I don't know what the exact volumetric efficiency of
    the six-port RX-8 is, but I would guess it is  no less than 100
    percent. So using that value, the spreadsheet shows 226 hp at 7000
    rpm and a best power air-fuel ratio of 12.5 at standard atmosphere
    an no intake restrictions.

    Another figure for VE that I've heard mentioned is 94 percent -- but
    I believe that is for the 13B engine. If we use that figure, the
    calculator shows 212 hp at 7000 rpm.

    I think this spreadsheet is a little conservative, if anything. It
    jibes pretty well with real-world hp data I got from Paul and Doug
    Fir on several different engines.


    Regards,

    Gordon.

That 100% figure is for an optimized intake manifold length.
Nobody so far has built an RX8 intake manifold near optimized
length to my knowledge.

Racing Beat put the stock RX8 high power engine with the complex stock
manifold on their dyno and got only 232 HP at 8500 RPM. Probably around
190 HP at 7000 RPM. Mazda is now claiming 238 HP at 8500 RPM.

The first attachment is what is involved with the stock manifold.

I think your simulation is too optimistic Gordon.

Here are our dyno curves for the Weber equipped P-port
second gen engine. Best BSFC occurs at the torque peaks.

I am building an RX8 engine version
as we speak. We will test it on the Mazdatrix dyno.

Jim Poole is building a special cutter to cut the cost.
We hope to get the cost below $100 each for the two inch P-port bores
in each housing.

Paul Lamar ...No rotor no motor.

Milo and Gordon,
I believe Paul will be proven to be right, as the complexity of the manifold
is what makes the difference in the RX8 power output.
A lot of research and testing went into that manifold, pity we didn't have
the source data.
George (down under)



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