For about 10 seconds after startup the active exhaust valves stay open. This makes for a much louder startup than some people (and neighbors) may want early in the morning. If you do this (below picture), and put it in gear right away after starting, you can wake up only a few families rather than the entire neighborhood. I just tested it by sticking a pin through the wire to tap into it. I haven't worked on an elegant solution like a hidden switch or other automatic activation since I don't plan to do this mod myself.





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Neighbors on either side have both moved out. Exhaust works as designed.