RE: Evolution TPS Engine Modification Experiment
If you can get a good tune within the stops, there is no reason to remove the limiter.
Typically however the engine requires a setting that is just slightly beyond the limiter.
More important is to prevent the "walking needle" problem.
The limiter collar particularly on the low end, tends to move when the plane is in flight and/or when the engine is warm during a run.
This can and will cause all sorts of problems, until you eliminate the walking.
The easiest way to do it is by putting a piece of exhaust tubing over the needle to hold the clip tight against the detents.
Another method is to remove the clip, and tighten it to add more resistance to needle movement, before re-installing.
Re; Muffler baffle.
Yes.
Open muffler, remove baffle, put it back together with a bit of loctite applied.