Works From Stock to Big Power Builds In stock form, the R35 ECU measures airflow using a Mass Airflow (MAF) sensor located in the stock intake system. As modifications add up and increase power, the airflow can increase to the point that it exceeds the MAF sensor’s maximum capacity, preventing the ECU from accurately measuring air mass, and thus unable to deliver the appropriate amount of fuel. The Big SF Intake increases the inner diameter of the intake tubing, increasing the cross section of the intake and allowing the MAF sensor to read lower for the same amount of ingested air. This gives the sensor the necessary headroom to read accurately for airflow higher than the stock system was designed for. COBB Tuning has used the Big SF Intake to support builds of over 600HP and 600TQ at the wheels, gains of 40% over a stock GT-R!