exhaust theory

[ChrisH]

Lots of newer bikes are using stepped exhaust now.  Anyone seen anything like this on a 2v Duc motor?

In my experience, and opinion, stepped exhausts are a nice compromise. The smaller section near the head will aid in exhaust speed until it meets the step where the pipe then allows for increased volume. I think length of piping, ID of piping, and the shape of bends has a more significant role in efficiency & horsepower then where the pipe terminates in to 1 or 2 cans. After a certain point, it comes down to compromises for cosmetics, or money.

[jeff137]

Just be glad we're talking 4 stroke engines.  Anyone that's ever ridden MX will tell you that the smallest dent in a 2 stroke pipe can mean huge power losses.

Thanks for all the posts on this topic. It actually is interesting reading to a bystander like myself.   

[jerryz]

2-1 seems to do wonders for some HDs and old Triumphs giving more torque for certain. However when i raced HDs i found that seperate open tuned pipes gave most revs and sheer power so long as the back pressure was tuned correctly. and the sure were loud.

Ducati is a different beast completely and i cant see any benefit in 2-1  espacially using C/F components.

[supertjeduc]

2-1 seems to do wonders for some HDs and old Triumphs giving more torque for certain. However when i raced HDs i found that seperate open tuned pipes gave most revs and sheer power so long as the back pressure was tuned correctly. and the sure were loud.

Ducati is a different beast completely and i cant see any benefit in 2-1  espacially using C/F components.

Builders like NCR and Pierobon always use 2 in 1 systems , they are much lighter and i think you don't get less power

[Raux]

yeah but it can't be the same inner diameter as the stock dual exhausts