Hi, I have just had a BM Catalysts BM91006 cat fitted to my 1999 AP1 S2000 and it now comes up with a P0420 fault. Would a MN91006H (Homologated version as needed for a post 2001 car) stop this error as it has more active catalyst to meet the euro 4 requirements. Also would this cause an increased back pressure and cause any issues with the AP1 revving to 9000 RPM?
Secondly, the shape of the BM91006 cat does not allow the OEM heatshield to be fitted on it so do I need a different heatshield or should it run without one?
Thanks.

 

I can be bad to run without the shield! Can you say fire?

 

Your concern should be passing emissions, inspection, and MOT vs hitting 9000rpm with an antique car.

-- Chuck

 

The catalyst is not meeting the P0420 requirement.

Adding one spark plug spacer to the rear o2 rectifies the P0420.