2011-2012 Duramax LML HSP Cold Air Intake (502-1-HSP)2011 2012 Duramax LML HSP Cold Air Intake (502 1 HSP) The HSP Cold Air Intake delivers an average of 20 additional horsepower and 58 lb ft of torque. This is achieved through a 4. 5" mandrel bent aluminum intake tube, which ensures consistent, unrestricted airflow. The included heatshield box blocks hot engine air, allowing only cooler, denser air into the system which translates into more power and efficiency. CNC machined sensor blocks guarantee a