under engine motorcycle exhaust 2

[12rich57]

Hello to the experts,
I have a question regarding the feasability of running an under engine exhaust system exiting in front of the rear wheel for a GSXR 1000 project.The machine will have a trellis frame,swingarm,linkageless shock and no fairing.Would there be any adverse effect on running short(600mm) small diameter(30-35mm)headers into 45mm collectors then straight into a muffler of approx.600mm?(which would be of similar capacity to dual cans found on common sportsbikes)The main question is what is the difference between short small headers compared to longer large ones?Short fat pipes for top end and long small ones for torque lower in the range but is there a middle ground?I am very interested to know how the sonic waves and gas speed would respond to my 4 into 2 idea.

 

[CorBlimeyLimey]

You may want to try forum668

 

[BrianPetersen]

I poked around with this when I designed and built my own header set for my FZR400; that bike is old enough that the only manufacturer still making exhausts for it is the one that makes garbage IMO (and I'm not naming them).

Any chance of increasing the primary header diameter to about 38 - 40 mm? 35 won't be too bad, but smaller than that will start choking off the top end power because the exhaust won't be able to get out fast enough.

Having basically primary headers only and no secondary length of pipe after that junction will cost you some mid-range torque.