questions about the exhaust note

[Hu_Dat?]

1.) I realize that four bangers make a higher pitch sound than a big V8 or v10 but why?

2.) Why exactly does puting a bigger muffler on a four cyl lower the note? I know they take the silencers out but my question is why does it make it lower? is it the width?

3.) what can you do to alter the note besides rev higher or getting a huge muffler (I'm mainly interested in raising the note of a V8 but not enough so that it dramatically hurts the hp)

THanx in advance

[matt horton]

y would u wana rais da note ov a V8, dont u tink day sound kinda cool wiv a supa low note

[SaabJohan]

The sound of an engine is firstly defined by the number of combustions it does per time unit.

For example a F1 V10 engine at 18,000 rpm will have a sound of 1500 Hz, a 4 cylinder engine at 8000 rpm will have a sound of 266.7 Hz and a V8 engine at 5000 rpm will have a sound of 333.3 Hz.

The next thing that will affect the sound is the ignition order, followed by valve timing.

Then we have the exhaust system, tube sizes and length affect the tuning of the sound just like they do on a church organ.

The silencers usually consist of some sound absorbant material (usually some fiber), otherwise the simply "smooth out" the pulses. An important issue is to tune the pipe so we don't have any annoying resonancing sounds at the rpm:s commonly used in daily driving.