Group,

 I want to remind everyone about how much a priority the large volume inlets are to us. I believe Ed Anderson was mentioning in one of his posts how difficult it can be to get a MAP signal in the airbox of one of our PP engines. This is a perfect indication of why the smaller throttle bodies used on some of the slow turning engines will kill our HP. In a high turning engine, rotary or piston, wide open throttle will often result in very low vacuum in the inlet for considerable time until the engine reaches steady state.  On of the reasons for a tuned intake is to get the air moving and keep it that way until the ports open. That is how the rotary can achieve better than 100% flow efficiencies. Our engines are better compared to the motorcycle engines I used to build than a Lycoming. An example with which I have a lot of personal experience, a Yamaha FZR 1000 is a perfect for comparison.  Engines I built were dynoed at over 160 HP at 10k RPM. This is from 1 liter. This output level isn't even exceptional as this engine was used for endurance racing. Many make lots more! Some of the 2-stroke 500cc Grand Prix bikes were producing over 200 HP at the end of the 2 cycle formula! These engines would not have produced 1/2 that using 1 Eliason. The Yamaha used 4, (count 'em), 4 43mm flat slide downdraft carbs. The  only way to get the power we expect is to process lots of air. We are also usually trying to keep the airflow at somewhat less than supersonic velocities which would complicate tuning even more. Plan to use a good injection system, even if you don't use a full EMS. Leon's comments are correct however abrasive they may seem. You can buy a small O2 sensor based tuning aid from lots of sources for less than 80 bucks. Do your initial tuning on unleaded premium auto gas and you can ground tune with a good indication of if you are somewhere close before ever even taxi testing. (which you should do to check dynamic effects before flying) Using a dyno is even better. Using a paraphrase of an old machinists saying, Test twice, fly once. (successfully!)

Bill Jepson