What causes exhaust "farting"?

[paranoidTSi]

Just curious, I see a bunch of hondas that do this and others don't what exactly causes it?

Plus I just put on a 3" downpipe to complete my 3 inch exhaust system, now when I take it up to about 4 to 5K it makes a good ol' Honda fart. It still sounds mean as hell, but I was just curious what causes it?

 

[Megaman]

running rich..a vented bov will cause it to pop more also

 

[noz]

do you mean when your car backfires because its running rich?
farts when you shift right?

 

[noz]

its no good for your car

 

[DSMSpyder99]

get NGK BPR7ES and some Magnor 8.5mm Wires and the backfiring will go away. It did for me at least

 

[Defiant]

An air leak in the exhaust can cause it, too.