iv got two dump valves for my gto (see pic) there both recirculating valves the black one is standard (crap) and the silver one is a piston valve but its dual port so it has a second vent so it 50/50 i dont want turbo lag so i cant decide
can you not pull out the return feed for the air that goes from the DV back into the air line (the bit that makes it recirculating) so it dumps the air into the engine bay therefore making it an atmospheric one, or would confuse the air flow sensor??