I don't think it is all that sensitive
Any change will change the air flow but I think you can work with it to try to optimize the cooling air flow for speed. Last year I experimented with the intake by making bolt in plugs to reduce both inlets from the inboard edge by 1/4" increments and measure the effect on CHT and air speed. I saw virtually no change in airspeed but the CHT's increased consistently with the reduction in inlet size. If you look at production aircraft you see some (Piper for example) with ramps molded in as part of the inlet and and some are just round holes with a short circular flange dumping air into the familiar baffle configuration in front of the cylinders. I think you are considering straight sealed ducts leading into the plenum area (either closed on top by the cowl or a separate inside the cowl hard top). If there is no air deflection in the inlet you MAY find that the forward CHTs are much colder than the rear ones. If your desired results are not achieved with your initial attempt, you will have to work with it to see if you can make it better. Ramps or deflectors are part of the option list. My inlet modification results to date have not been productive in increasing speed but I have other ideas in this area that keep simmering in my brain.
Bob Axsom
