I am heading to Haarlem in the Netherlands for the IMBRA race in August. I have been working on new muffling but am having trouble getting the db under 82. The exhaust is quiet on the bench so the intake is beginning to dominate the sound level. My meter shows a drop of 4 db between the engine compartment and the exhaust area when it's on the bench.
My fellow Euro boaters, any ideas on how to dampen the intake noise. I've lined the cowl with a layer of foam rubber but I still have an open top which may be allowing the sound to escape. I also wonder if the standard Eagle motor mounts are too stiff and are allowing sound to resonate from the hull.
As an interesting sideline, I've been finding the engine works better with the added mufflers. The higher exhaust pressure is making fueling more consistent and the engine stays on pipe better. At 3700 ft we need to push fuel into the carb as the normal draw of a big bore carb does not work in our thinner air.
My fellow Euro boaters, any ideas on how to dampen the intake noise. I've lined the cowl with a layer of foam rubber but I still have an open top which may be allowing the sound to escape. I also wonder if the standard Eagle motor mounts are too stiff and are allowing sound to resonate from the hull.
As an interesting sideline, I've been finding the engine works better with the added mufflers. The higher exhaust pressure is making fueling more consistent and the engine stays on pipe better. At 3700 ft we need to push fuel into the carb as the normal draw of a big bore carb does not work in our thinner air.