TIAL Q Stye Blow Off Valve BOV 50mm Black Up to 1800HP FAST US SHIPPING Turbo HDTIAL Q Stye Blow Off Valve BOV 50mm Black Up to 1800HP FAST US SHIPPING Turbo HD The best blow off valve on the market for street driven turbocharged and supercharged vehicles, with a stagger 60% more airflow than the original Tial BV50 design! That means 60% more air is blown off per cycle! CNC Machined to the highest standards from 6061 Aluminum, the BV50 features a large 1. 98" (50. 5mm) valve, among the largest in the world. A single Q BOV can