Why are us cars mufflers smaller than other countries.?
It is not a good idea, unless you really know the design philosophy behing each car, to compare the two. They are both GM product but that is pretty much where similarities end because of market differences. Both cars are a Holden, a car built in South Australia, and exported to the US as a Pontiac and UK as a Vauxhaul with some difference for each market. To each market they will be tailored to suit emissions regulations, and that most likely explains your differences. Note: this car is not an American or a European design: it is a derivative of the VE Commodore, Australia’s top selling model (most of the time).
