Quick (silly) question - why does having a full de-cat increase bhp and torque. I know that it allows the turbo to spool up faster and allowing the engine to breathe more makes it more responsive but what are the technical reasons for it upping power.

Is it literally the blowing through straw effect - the cat strangles the power?

Cheers
Paul

 

I'd say spot on explanation

 

has been known for the occasional car to loose power on renoval? dont know y possibly the need for a re map?