1997 XK8. Between the primary and secondary mufflers is a curved section of the exhaust pipe with oval cross section. I looks as if it was manufactured that way, but can anyone suggest why the round cross section was not maintained. It would seem to be a flow restriction.

G.B. Australia

 

You mean the exahust that goes over the axles? Yea they are crushed like that from the factory to make them easier to install and manufacture. Aftermarket exhausts are better and fix this problem. Adamesh do a Stage 1 and Stage 2 exhaust kit that repalces the over axle exhaust section so it's no longer as restricted. Once you take the section out it's pretty obvious how crushed the pipes are.