fwiw, I used a automotive water line hose (6 inch) to extend the breather tube onto the exhaust pipe. the breather tube burns to contour against the pipe. coldest temperatures flown -27C at high altitude and -20C at low altitude. no other holes in vent piping. this is only a data point and I fully support an additional hole in the vent pipe if you feel the need.
upper vent piping silicone elbow is holding up well.
![IMG_20150327_165903.jpg](/proxy.php?image=https%3A%2F%2Flh3.googleusercontent.com%2F-mMlYc8O26-c%2FVRcUjyaSgFI%2FAAAAAAAAEcA%2FjJcL8S0uDC4%2Fw426-h568%2FIMG_20150327_165903.jpg&hash=b79a5a78684f9205b3388d955148f52a)
upper vent piping silicone elbow is holding up well.
![IMG_20150327_165147.jpg](/proxy.php?image=https%3A%2F%2Flh3.googleusercontent.com%2F-4M1Dx8mkCMA%2FVRcYaxD86yI%2FAAAAAAAAEeI%2FSiyhC-XYuRg%2Fw426-h568%2FIMG_20150327_165147.jpg&hash=c94652f4e4076718bd32d981d7215ea3)
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