My simple comparison of the Stock muffler against the OS muffler with regards to sound? The 10cc in this video with the OS mufflers is running on its first tank and is running really nice on a APC 10x6 run-in prop at max RPM at almost 13k... amazing for a brand new engine... very easy to tune and very reliable..
Last edited by flypilot; 03-13-2018 at 06:15 AM.