The main reason i got the macs pipe was the weight savings and its small size. Changing the muffler brought my plane down to 4lbs 1oz. plus was cosmetically more appealing.

I was already running the factory muffler with the baffle removed (OS46 on this plane) i know macs doesnt advertise any power gian but i got a 400 rpm increase (not much but a little) might possible say it was because needle valve tuning, but i dont think so. Could instantly tell a difference in power when i stood the model vertical, im sure the difference in weight helped here, but i think it has alittle more power too.

On a 3d model a "tuned pipe" doesnt give the effect i want. Makes the pwer band "peaky" for lack of a better way to describe it. Plus a big tuned pipe is heavy.

Thanks for all comments so far.

Know back to the 50sx and the original question. Has anyone done any experimenting with drilling the exhaust hole on a macs muffler?

Reason im asking is The macs muffler is for the 40-46 size engine and im running it on an OS50sx and was just wondering if the larger motor would benefit from a larger exhaust opening.