EGR is bled pre-turbo - disabling EGR increases the amount of exhaust going to the turbine It's possible to tune a diesel without making smoke - normally this

EGR is bled pre-turbo - disabling EGR increases the amount of exhaust going to the turbine It's possible to tune a diesel without making smoke - normally this is done by leaving the wastegate closed for longer to make more boost and then adding more fuel. Any smoke is too much extra fuel.