instead of using round tubing for the exhaust, why not use square? wouldnt it make more sence for a car that doesnt have a lot of ground clearance? im just talking from the y pipe back to just over the axel then swithing back to round for the mufflers and tips. would this be a bad idea?

There is oval pipe that some use, instead of round for that very reason. Later.

Having round exhaust pipes provides the quickest exit of exhaust gasses possible. An ideal exhaust system is perfectly engineered, round of course, and fitted to the perfect length, which will promote quick exhaust exit, and exhaust scavenging which in turn provides more power. The idea behind quick exhaust exit is that the exhaust pipe should theoretically get smaller as it moves farther and farther away from the headers/y-pipe so it keeps moving quickly out of the exhaust system, resulting in a "sucking" action, if you will. Opposed to an over sized exhaust system that provides no low pressure to quickly exit the exhaust gasses.

This is why mandrel bent exhaust systems are advantageous and provide more power, because smooth curves promote quicker exhaust exit, not like square or rigid pipes which would cause too much reflection of the gasses.

Hope this helps.

ok that makes alot of sence thanks

Check out drgas.net for an assortment of oval pipe. Later.