Performance Car Air Filter Test
Panel Air Filter Restriction Test
As not everyone wants to remove their standard airbox, we also restriction-tested a few standard panel filters in exactly the same manner as we did for the cone filters. The entire airbox assembly was fixed to the end of the rig, and we increased the flow rate incrementally and recorded the pressure increase to see which offers least restriction.
The first thing to note was just how restrictive the standard assembly really is, so much so that even with the rig running flat-out we couldn’t achieve the 6.75m3/min flow rate we used when testing all the cone filters. That wasn’t a major concern, however, as Tony had calculated that a standard Ford Fiesta ST only requires a maximum of 5.5m3/min, and as the same flow rate would be used for all three tests, we could still make a direct comparison.
It was also worth noting the most restrictive cone filter we tested had a pressure of 1.21kPa at 6.0m3/min, whereas the best flowing filter within the standard airbox was 2.56kPa.
Overall, we have to conclude that if you want maximum performance from your engine, a large cone filter is definitely the way to go over a standard airbox.