aFe MagnumSHIELD Pre-Filters P/F 18-09001 (Black) FOR0050020SL press "OFF" and the valves

press "OFF" and the valves will operate as if the device wasn't installed

allowing your ECU to properly map timing and fueling for the higher boost levels

Applications: 2008-2014 Subaru STI & 2011-2014 WRX

but when the engine is at high load (WOT)

aFe MagnumSHIELD Pre-Filters P/F 18-09001 (Black) FOR0050020SL press "OFF" and the valvesaFe Magnum Shield Pre Filters protect your performance air filter and extends your filter cleaning intervals by removing large particles from the air stream prior to the air filter. This pre filter does not restrict air flow and is made of a dry weave fabric that does not attract dirt and cleans with soap and water.