what makes one exhaust system better than another? is it the diameter or the way its bent?(the head pipe) im talking about 4 strokes more so than a 2 stroke. thanks

 

Just better airflow

 

with a naturally aspirated engine you need some back pressure. if that true?



thanks

 

Exhaust size and length still has a part to play in a 4-stroke, but a correct pipe for a 2-stroke can make them or break them. It's not so much backpressure on the 2-stroke, though. A correctly made expansion chamber actually bounces the waves back at the exhaust port just a split second before the piston covers it up. That pushes some of the raw fuel back into the cylinder for a more complete filling and that makes more power. Naturally the head pipe length will help determine the rpms at which the pipe works the most effectively, but these are just some of the basics. The reason why everyone doesnt just make a pipe is because there is a ton of R&D and money involved.

 

Its my feeling that there is a correct pipe for each motor. Production pipes will get you close to what you want, but not exactly. They say the first 10 horses are easiest power to make. Its the last 10 horses that will be the hardest (that in mind i know you guys make more then 10 horses initially). The last 10 horses has to do with the correct combo. If you want the power the pipe should be hand built. Bubba had it pretty close to a good definition on the correct way a pipe should be built, and how it should perform.