[Guest]

i have standard downpipe cat replacement pipe and midsection replaced and hayward and scott back box normally but i have replaced it with the standard back box for testing i was complaining about the noise in the cabin of the car everthing is ok when you drive normal but if you give youre evo really a hard time more noise is comming into the cabin a dark loud noise

why is this happing

so it's not the backbox which give the problem it comes somewhere from the cat or middle section

andre
going sideways

 

[Guest]

Maybe i should put back my original middle section back on and keep the decat pipe and put the hayward and scott back box back on

what are the bubbles in the midsection pipe some kind of cat or are these things keep the sounds down how about the gas flow in the middle section very bad?

regards

andre
going sideways

 

[Guest]

Andre,

Might be the old OEM exhaust is leaking already, so when you floor it, the gas escapes from the small leaks and since they are pressurised, they might be causing some noise.

It could also be the old OEM muffler is leaking too. Check the weld points.