Blow Off Valves - How do I know which valve spring to use?Updated 3 months ago

All of our springs are rated based on the amount of engine vacuum required to open the valve with that particular spring installed. In order to select the right spring for your vehicle you should take into account the amount of engine vacuum generated at idle, the vacuum “dip/spike” on initial deceleration, and what style of valve you are using (Plumb Back, Dual Port, or Supersonic).