can anyone tell me the differance between the two exhaust boxes on your average car. I believe the front to be an expansion box & second to be a silencer, can either be used by itself on a locost & which works best

thanks all

an expansion box is useful for tunning a car as long as its big enough to cope with the pressure waves hitting it. Do a search on Ron Vizzard and exhausts. He did an interesting article how the expansion box can be used to get the tunned lenght of the exhaust spot on and then the 'muffler' can be used to quieten the car with minimal performance loss.