Let's run through quickly what an air filter does before we get into the review. The primary purpose of an air filter is to remove fine dust/pollen/dirt etc. from entering the engine's cylinders where it would cause mechanical wear and oil contamination. A blocked or dirty air filter will also cause poor performance and increase fuel consumption. Air filters should never be cleaned with compressed air or banged out on a table - this will only leave a false impression that the filter is clean. Air filters need to be changed every 10,000km to 15,000km or every 12 to 18 months. Most modern day vehicles now use a paper filter element placed inside a plastic box connected to the throttle body. The main reason for using a paper element is price rather than performance.
We decided to go with a BMC air filter in our project E92 M3 based on a number of reasons listed below.
- They have over 9000 vehicle applications and had one which fits directly into our project car.
- Replacement filters are created from aluminium net treated with epoxy resin and guarantees resistance to fuel vapours and oxidising due to humidity.
- The filtering material is special cotton soaked in low viscosity oil and guarantees greater permeability to air.
- BMC filters can be cleaned and re-used by using one of their regeneration kits (detergent and oil spray).
- Filters are designed to flow more air than the standard element, allowing for a slight performance increase.
- The price of their filters is reasonable and is available for purchase at a number of locations.
Installation was quite simple. Open up the standard airbox, remove the standard filter element and drop the new BMC replacement filter in. Close up the standard airbox again and testing can begin. Upon starting the car, induction noise had increased slightly while not being over the top. While BMC's air flow chart notes that the filter flows better than the standard one, we were unable to feel any noticeable difference performance wise driving the car around town. Having said that, if we were to do a back to back test on a dyno it may tell a different story. An online source has quoted a 10hp increase on a Dynojet dyno after installing a BMC filter.
BMC Air Filters are designed and manufactured in Italy and were originally developed in association with the Ferrari F1 team. The quality of the filter definitely speaks for itself. We would recommend this product for anyone in the market of looking at replacing their air filter and we welcome any feedback from those who have done a comparison dyno run after installing one. You can purchase these filters HERE for those interested.