can anyone help

[billabong1992]

Hey guys and girls just fitted a ktec janspeed cat back exhaust and now have a weird whistling noise when I go over 4000rpm any ideas??

 

[jesus]

It's blowing at the cat to centre section join.

 

[Steveball]

Local custom exhaust place will weld the joint for sub £30

 

[GrahamS]

Turn the car on whilst on some ramps. Get under it and feel for the leak. It will be obvious!