Denk

Not your ordinary exhaust question. In all the posts I've read, everyone talks about length and not shape. Can anyone tell me the importance of having either an oval or round shaped muffler? Is it simply a clearance thang? For a muffler that is 4x9 and one that is 5x8, as the magnaflows are, and having the same area inside, do they make a different tone?

At this point, magnaflow has 4 different models to chose (my choice is the 18" with 2.25" in/out):
4x9 oval
5x8 oval
4" round
6" round

Can anyone make some sense of this for me? Thanks.

Henryv

Hey searching actually works! haha j/k. Well I've been wondering the same thing as the original post so does anybody know the answer?

mike_d

yes, they should make a different tone. the tone is due to the resonant frequencies inside the muffler. since just about all frequencies are coming out of the engine, when they go through the muffler, some reflect off the walls of the muffler and add destructively, and everything get's quieter, which is what a muffler is for. however, some frequencies can reflectand add constructively (or at least less destructively) and those frequencies will come out in higher proportion at the other end. generally a larger muffler will allow the lower frequncies resonate better than a smaller muffler. if you have an eliptical muffler, you'll get a different pattern of resonant frequencies than a round muffler. i don't feel like writing the code to simulate/calculate it, so i can't say exactly what will happen, but as a zeroth order approximation, i'd say something like a 4x8 oval muffler will have the same frequencies as a 4 and a 8 round muffler but in lower amounts than either one separately.