I ran my K .90 using the SuperTigre Swing Quiet muffler and the Macs Black one piece. My wife complained that the Macs was much louder even at the lower rpm.


Fuel Fox 5% nitro with 20% castor.
Prop APC 14x6 RPM with the Swing muffler==10,877
RPM with the Macs one piece========9,900
Plug==GloDevil====2 stroke standard.