Outlet Diameter of Chamber Stinger

[Vintageman]

Is there an optimal way to calculate the diameter of the stinger outlet (in my case baffle) of expansion chamber?

My reasoning if too small too restrictive to high RPM flow. Length matters as well , but wonder if there is a guideline for calculating dia of the stinger section.


I have a set of 3 into 3 Bassani’s on my GT550, The ID of the baffle is about half that of my Jemco 3 into 3s baffles on my GT380. But I wonder if the diameter is too small on the 550 and limits higher rpm ( +7000 rpm). The Bassani's are much quiter then the Jemco's

I did not try running without baffles since the sting pipe is integral to the exhaust design. These baffles are just inserts. I suppose if I did remove baffle and run that it may prove the point , but just wanting to know if any theory behind this selection on outlet diameter.

[Vintageman]

maybe 2nd page of this article

and page 58 as stamped in the article emphasis dia is important

http://www.bridgestonemotorcycle.com/do ... eally6.pdf" onclick="window.open(this.href);return false;