How does the baffle work?
 

If I just remove the baffle from the stock muffler, will I gain anything. Or will I also need to drill out the opening. I know peopel have gained power form doing both, but I was wondering if removing the baffle alone will realize any gains. I was thinking since the muffler aft opening is smaller than the hole at the end of the baffle, wouldn't that be the limiting facture of how fast the exaust gases escape the muffler. This is the baffle on an OS 91fx, which is basically a cone with a hole at the end of it.

Then again maybe removing the baffle will help with the pressure waves bouncing back more so that it creates more power. I would appreciate if someone could enlighten me as to how the baffle works and also what removing it will do. The baffle is only there to muffle the sound more, correct? Or does the beffle somehow direct the pressure wave out rather than back to the motor. The shape itself seems to me to do just that.

RE: How does the baffle work?
 

Removing the baffle without doing anything else to the muffler will result in a slight power gain as it will allow the exhaust to expand more before hitting a restriction. It will also increase the noise level a bit, but it won't be that much louder. No, the baffle does not give a "tuning" effect with the shock waves. The baffle is far too close to the exhaust port for this to happen.

John

RE: How does the baffle work?
 

The baffle in a typical r/c muffler is a simple restriction that has the effect of lessening noise to
a degree, and in some cases improving the idle qualities of the motor.

Before mufflers were commonplace, many r/c engines used a butterfly valve over the exhaust
opening on the cylinder to help increase back pressure at low throttle operation. This helped retain heat
and improve the idle somewhat.

It could be theorized that the purpose of the baffle is to restrict the free access of the hot, expanding
exhaust gases to the atmosphere. If those gases can be contained longer...they are allowed to cool somewhat
before exiting, thus yielding a reduction in noise.

Removing the baffle does not "increase" power, but rather reduces the amount of power loss when
compared to the open header measurement.

'Race

RE: How does the baffle work?
 

Anthony,

A muffler baffle essentially makes a single expansion chamber muffler, into a dual expansion chamber muffler.

For the front chamber, the rear chamber is an "atmosphere", into which it spews the exhaust gasses, through a large exit hole. The pressure fluctuations at the baffle hole are smaller than at the exhaust port, so the rear chamber has less of a noise problem to deal with. It, in turn, spews the exhaust into the real atmosphere, through a smaller exit hole.

To achieve the same sound attenuation with a single chamber silencer, you would need a much larger volume unit, than with a dual chamber, but the power loss is greater with the smaller dual chamber.

Since quelling the high pitch "whine" of a two stroke, at the lowest cost, is the target; small, baffled silencers are the norm.