E55 catalytic converter removal

[E55BOF]

When I was buying the car (1998 E55 AMG), somebody advised me that if a cat or cats break up, removal of the remains of the matrices will restore normal running. Would this improve fuel economy, would it upset the mixture and risk harm to the engine, and what about at MoT time - would it (like a Saab 9000 Anniversary I had) still pass the emissions test for pre-2001 cars?

E55BOF

 

[andy27168]

Hi,
As the 55 has 2 primary and 2 secondary CATs, removing both of the lower (secondary) CATs the car will still pass the emissions and it may release additional BHP and torque. If yours are rattling you could remove them and smash the guts out of them with a steel rod and empty them.
Alternatively you could have a chat with Olly (PCS) who use to do complete decat replacement pipes, his pipe would also remove the centre resonator box as well.
I have had one of Ollies decatt pipes on my car (55 engine) now for about two years now, and it has passed the MOT emissions with no problems what so ever.