Brock’s Performance does not currently recommend or endorse the use of ANY BRAND aftermarket “street” filters. It has been our experience that they do not perform as well as stock and can actually work much worse. The reduced air flow compared to stock; disrupts our known good mapping, decreases fuel mileage, hampers driveability, significantly reduces power levels, fouls plugs, creates excessive soot at the exhaust tip, generates excessive carbon deposits in the intake track etc. When over-oiled we have seen these problems increase dramatically with registered horsepower losses in the vicinity of 10-15+ with greatly increased fuel consumption. You can't go wrong with today’s modern OEM air filters, in regard to engine life and consistent performance.

We have noticed measurable performance gains when using both K&N and BMC aftermarket “race” filters compared to stock, but these filters are for racetrack or low mileage use only since they basically filter out bugs and birds!

Registered Brocks Performance exhaust system owners can read additional test details in our private owner section linked below (see note 18):