Air Filters and Flow Air filters are clearly essential for engine life. Properly fitted they will improve power by ensuring a good supply of clean, cold air. There is a lot of hype about filters improving power. Some certainly do but only when they improve upon the existing set up. Fitting a cone type filter such as a K and N 57i or BMC VAS may well improve flow, and possibly throttle response but if the filter then draws hot air from the engine it will not improve power. In fact it could well reduce power. The same applies for airbox drilling. We have read of lot of information on filters over the years. We personally feel cotton gauze are the best ONCE they have had time to develop a layer of dirt to increase filtration efficiency. In terms of flow we feel they are superior. However in terms of dirt filtration we were surprised to read the results of a test which showed that foam were much better in multilayer style than cotton gauze for filtration efficiency alone but from a flow perspective once slightly dirty they lag behind cotton gauze. Filter types compared from a perspective of Air Flow
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As you would expect, the paper element finished third It captured around 120 grams of dirt over an 11 minute run before the filter became clogged and registered the pressure differential drop on a manometer of 6 inches of water. The starting reading was 17.84 inches of water, and the ending differential was 23.84 inches of water.
The RamAir (similar to Pipercross) multi-stage foam filter finished first in dirt holding holding capacity. It captured a massive 199.81 grams of dirt but with a larger starting and ending pressure differential. This means the foam filter works well out the box but less well with a layer of dirt.
The cotton gauze filter (BMC air filters K&N and Green all use cotton gauze) finished second in terms of filter effciency with it capturing 140.08 grams of dirt over a 22.8 minute run before the filter clogged up and registered the pressure differential change of 6 inches of water. HOWEVER the start pressure drop was just 16.8 inches of water making this the best all round filter material. The starting differential pressure was 16.80 inches of water and the ending pressure differential was 22.80 inches of water.
Balance Motorsport can offer the superb range of BMC Filters including the Carbon Dynamic Airbox. This device ensures a supply of cold air to the filter and using a venturi effect and front air intake actually increases the velocity and volume of air being drawn into the engine. If the airbox is not listed for your vehicle we can either custom design and install a setup for you or if you are too far away you can order a range of pipes and clamps that should enable you to install a CDA on any vehicle. We still offer cone filters from BMC but remember with these to focus on getting a good cold air feed. In addition have a look at our Heat Management products. If you can reduce underbonnet temperatures then you can probably increase power.