OK, I just got a GMS 47, the muffler seems to be longer than the one on my OS 40 FX. I've heard that longer mufflers are better at performance.

I was thinking of replacing my OS 40 FX's muffler with the one on the GMS. Will it increase performance?

Zeng,

The Tower/GMS/Hobbico muffler will give you about 400-500 RPM more than an un-baffled OS 783 silencer, on larger props in the range; 11x6 for instance. On smaller 10x5-10x6, or 9x7-9x8, it could add as much as 1,000 RPM. It is a rudimentary tuned muffler.

Fuel consumption will increase accordingly.

Ooooo! Just what I needed!

Have we met before?

Anyway, my OS muffler has been modified, theres a little round thing inside the muffler that was removed, as I was told it was restriciting performance. How much RPM will that increase? Can I do the same to the GMS muffler or is there no such thing inside?

Zeng,


This is precisely what "un-baffled" means. The baffle is that round, conical, perforated thing that you removed.

The performance difference is with the "un-baffled" 783, as my previous post says.

The Tower/GMS/Hobbico doesn't have a baffle.