Dinan High Flow Throttle Body - 1999-2003 BMW 540i/1999-01 740i/2000-2003 X5Dinan's High Flow Throttle Bodies improve intake airflow for additional horsepower and torque gains. The internal diameter of the stock throttle body is bored larger increasing the airflow area. The resulting increase in airflow provides more horsepower and torque throughout the RPM range with noticeably quicker throttle response. The throttle body is 3mm larger for an 8% increase in airflow area (Stock bore 79. 5mm; Dinan bore 82. 5mm).