Where is a good source for instructions on adjusting the length of a tuned pipe exhaust system? I've found instructions on Jett Engineering's FAQs. Just curious if you guys know a different or better source of instructions for someone who has never attempted to get the best performance from a tuned pipe system. I just installed a new Rossi 61 rear exhaust on a T2A MKII that replaced a Webra 61 that was on the plane. I left the original tuned pipe from the Webra in place. Right now I have a 11X7.5 prop on the Rossi and get 13,600 RPM. The Rossi engine is new(break-in accomplished) and had three flights on it today.