09-02-2015, 04:15 PM
You want free flowing for top end. You want 'some' restriction for low end torque. It will be a compromise as everything is with engines.
Try driving a HDi with a decat, noticeably less bottom end torque so I always the cat myself. In regards to the cat, it is needed for MOT which is why they want you to fit one.
Try driving a HDi with a decat, noticeably less bottom end torque so I always the cat myself. In regards to the cat, it is needed for MOT which is why they want you to fit one.