Stryker_Viking

No, you don't need a muffler...

What you do need is a tuned pipe!

A correctly tuned pipe will increase the power significantly.
I remember back in the days (30 or so) when I tuned a pipe for the first time.
Had this tired 60 engine that couldn't move my plane as expected, so I purchased a pipe.
Installed it "loose" so I could adjust the length while running the engine, and I'll tell you - wow...
The engine was running at max throttle as I slowly pulled out the pipe when I suddenly hit that sweet spot and could hear the rpm increase at least 25%... as if a turbo kicked in...
Couldn't believe it, but I'll tell you man, that's the only way to go.
If you want to go fast that is...

Stryker_Viking

[link=http://www.mh-aerotools.de/airfoils/pylon_engines.htm]F3D Pylon Racing Pipe[/link]
[link=http://www.webra-austria.at/motor.php?search=AERO%20TUNEDPIPE&folder=SILENCER&lang=]Webra Tuned Pipe[/link]