Ever wonder what's inside that gigantic factory muffler? Why is it so heavy? Well, we wondered those same things. The answers can be found by taking an old stock muffler over to the band saw and slicing it right down the middle.
Here's what it looks like:
Wow! Pretty complicated huh? And no wonder it weighs 20 pounds! So what happens to the exhaust pulse after it travels down the head pipe?
First it dead ends into a flat cap on the end of the mid pipe and gets forced out of side slots in the end of the mid-pipe. Then it gets pushed through a 'cheese grater' perforated panel.
After that it bounces around in the forward chamber of the muffler and then goes through 12 small holes in a tube that connects it to the middle chamber.
After exiting the connecting tube it bounces around in the second chamber and eventually finds the way into a second connecting tube.
Finally it has to navigate a little maze through the third chamber and finds its way to freedom.
Is it any wonder that the stock muffler makes the engine feel stuffed up?