HI THERE
I'VE THIS WILD THOUGHT..... AS I LIVE IN THE MIDDLE OF THOUSAND ACRES OF OIL PALM PLANTATION ESTATE NOISE IS NOT AN ISSUE
SO IF I FLY A MVVS WITH OPEN EXHAUST(NO SILENCER) WILL I GET MORE.......OR LESS POWER
AND WHAT PRO AND CONS I WOULD FACE
MANY THX

Dino,


With a gas engine, you will get more power with an open exhaust, than with a Pitts muffler, or another restrictive exhaust.
This is also true of glow engines, but then you will have a very bad idle quality and transition.

When compared with a tuned muffler/pipe, or a canister muffler (45 and 58 cc), the quieter mufflers make more power than an open exhaust. So why suffer with all that noise.

With a good full length tuned pipe, you will have more power. If you do want to use the open exhaust, do not use the header pipe. An open tube will restrict rpm because the pipe keeps extracting mixture from the cylinder, instead of stopping the gas flow out the exhaust port. The open end of the pipe reflects a suction wave. When that wave reaches the exhaust port, it is again reflected as pressure wave, and the thing goes on until it eddies out.
Example:
My 50cc racer produced 10 hp on a muffled tuned pipe, and could be run up to 14000 rpm peak. Tuned range was 9000-12000 rpm. It could not be run below 8000 rpm due to carb duct length tuning. (engine would flood)

With the stub exhaust, noise was terrible, and the engine produced only 4 hp whilst hardly exceeding 8000 rpm. On the up-side: Carb flooding was no issue any more.

ROGER THAT
THX GENTLEMEN