a4 tdi 170 straight through help!!!!

[cookie 1984]

hi, i have a audi a4 b7 tdi 170 been remapped then i got straight through twin pipes, but the sound was not realy any different to normal, sometimes when its been driven hot the exhausts change sound instant to a real deep sound and this sounds how it should but then after 5 mins of driving it goes back to normal. anyone know why this is. is the ecu remap?
thanks

 

[astradti16v]

Have you still got the centre silencer fitted?

 

[cookie 1984]

no it never had centre section just had the twin boxes and dpf at front.