A catalytic converter comprises: (i) a casing (120) with an inlet and an outlet end (111,112); (ii) a first catalytic substrate (122) extending from the inlet; (iii) a first lengthways axis (124) set by the substrate, along which the exhaust gas flows; and (iv) a second catalytic substrate (126) extending from the first to the outlet end, and setting a second lengthways axis (128) which cuts the first by a set angle. The exhaust gas flows through the second substrate parallel to the second axis, changing direction between the first and second substrates.
