An Atmospheric Dump or Blow off valve suitable for all turbo cars without an Air Flow Meter. Made from billet alloy and using a single piston this valve will run faultlessly without the need for attention and eliminates the longevity problems associated with the original diaphragm valves
Single-Piston/Diaphragm Atmospheric Valves and Valve Fitting Kits
"All Forge Motorsport Single-Piston and Diaphragm Atmospheric Valves have been designed and built with the intent of venting 100% of the residual charge air remaining in your forced induction system to the atmosphere at throttle lift.
Forge Motorsport nor any of it’s Authorised Distributors can assume any responsibility for any adverse effects resulting from the installation of this valve onto a vehicle whose engine-management-system, whether factory or aftermarket, is not capable of compensating for the loss of metered air through a vent-to-atmosphere valve such as this. "
To view a spring tuning kit for this valve click here: http://www.forgemotorsport.com/content.asp?inc=product&cat=&product=FMDVTUN