It runs like shit, don't do it. I ran mine open for a while cuz I need the unmetered air from the recirculation pipe (no 2G MAS), it boosted funny, and didn't run very well at all. (too rich at times)Since then I put my 2G on and it runs great. BTW don't ever buy a Blitz I BOV. They sound good open. Can't hear shit closed. It sorta sounds like sticking a knife in a pig..*shoooop*