The only Ford-endorsed Mk2 Focus RS airbox upgrade - as used in the Focus RS500 and MP350 upgrade...
mountune’s involvement with the mk2 Focus RS began more than a year before the vehicle’s public debut back in 2009. From the outset it was clear that to increase the power output significantly, an improvement to the airflow capacity on the RS’ OE intake setup would be required.
mountune’s engineers set about designing a revised Focus RS airbox and inlet spout that would surpass any of these airflow requirements, whilst retaining the original look and feel you’d expect from an OE component.
Unlike other examples on the market, the mountune Focus RS airbox has been designed and tested to meet OE standards, and was also subject to extensive rig testing.
Independent testing showed up to 17% less pressure loss than the OE fit part, equating to more than enough airflow for 400PS+, as demonstrated on the now infamous mountune Focus RS MP350 and Focus RS500.