Will changing to to de-cat pipe cause me problems or will map need a tweek?

2005 sti PPP, remapped by Andy Forrest

 

i would think it would need a check and perhaps a tweak-probably better asking the man who mapped it

 

as above, if it's been mapped then the map will need adjusting to work properly with your new modifications. Time was spent calibrating the ECU to give the best performance with your catted downpipe - now without the cat there is less restriction in the exhaust so wastegate settings, ignition timing and fuel need adjusted again to match.

 

Thanks, gonna leave it till got bigger turbo then map from there.

 

deffo a tweek when you change anything to do with the petrol air flow and exhaust but many dont