RE: Power Decrease Using Exhaust Deflector.
PH,
On an MVVS .49 with the standard #3245 muffler, adding a Hobbico .35-.90 size deflector caused an immediate drop of ~1,100 RPM.
The cleanliness was limited to a more scattered distribution of the same dark oil.
An exhaust deflector is simply a waste of money, with negative consequences to the power.