Does a modified muffler change gas consumption?

Answer 1

Certainly a modified muffler on a 2 stroke-cycle engine will affect gas consumption and power. The reason is that these engines do not have an exhaust valve to keep in the gasoline vapor until it has been fired like a 4 stroke-cycle engine has.

The "2 stroke" engine relies on pressure in the tuned muffler to keep the gasoline vapor from shooting right out of the cylinder before the spark plug ignites it.

With a "4 stroke" engine, there is an exhaust valve to keep the gasoline vapor in until it is ignited, and the engine isn't much bothered about muffler tuning, size, or even not having a muffler, at all.

Answer 2

In most cases, a modified muffler does not have a significant impact on gas consumption. The primary purpose of a muffler is to reduce noise, not to improve fuel efficiency. Other factors, such as driving habits and the condition of the engine, have a much more significant influence on gas consumption.