Well, it depends upon your definition of "a whole lot quieter".

The engine itself certainly makes less noise, but some (cheap) mufflers act more like amplifiers. For example, a Shuttle with the original can on an OS 32 is just as loud, or louder, than an Hatori on an OS 61. The Century "muffler" that comes with the Hawk Sport is another ear-buster on a 32.

Lots of variables at play with engines and exhausts. But generally speaking, the larger the internal volume of the muffler, regardless of engine size, the quieter the exhaust note.

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