increasing size of straight pipes

[swynx]

so i have a ohv 4.0, muffler cut off then some more pipe and a home brew down pipe to keep the noise away from the cab. i dont think it sounds to bad, and everyone else seems to like it, its not noisy on the highway or in town.

in various scenario's i read about guys saying that if you increase pipe size from like 2 inches to 2.5 inches, that itll give the truck more drone. is this true?

i thought about putting an aero turbine 2525, but i like the way it sounds now, i just want a bit more drone.

 

[RonD]

Pipe organs that use Flue pipes set the "note" of the pipe by its size and length, same air goes into each pipe but a different "note" comes out based on the pipes diameter and length.

Exhaust systems, after the collector, are much the same.
"the wavelength of the sound produced by an open pipe being approximately twice its length. A pipe half the length of another will sound one octave higher."
Larger diameter tends to reduce higher frequencies

 

[swynx]

so your saying to just decrease the length of pipe?

 

[RonD]

Larger diameter and longer pipe = deeper sound
Shorter pipe is louder

X pipes also increase power(not much but not nothing either, lol) and lower the tone, if you are running dual exhaust

 

[swynx]

its just a single pipe straight off the original catalytic converter. it was louder but i like it quiet till like 3k rpms then i like more noise. maybe ill try a different size piping off the cat.

i used to have a truck with a really short exhaust, it was to loud