secondary butterfly valves are under your air intake stacks in the airbox and control airflow to the throttle bodies. Throttle position does not necessarily reflect the same open position in the valves. rough example: 50% throttle = 30% airflow from valve depending on where you are in the rev range, FI maps etc. If you remove them you unrestrict your airflow a little bit because you only have your primary butterfly valves (underneath 2ndary) to control airflow. Correct me if I'm wrong guys. I think there is a thread on how to remove them on here somewhere. I personally haven't removed mine because I wouldn't think it would make that much difference for the effort plus I have a TRE which does pretty much the same thing.
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