Replacement filter or intake kit?

• Replacement sports air filter (K&N, BMC): it takes the place of the paper filter in the original airbox. Its oiled cotton gauze lets more air through and is cleaned rather than thrown away.
• Intake kit (for example APR): it replaces the airbox and ducting with an open or closed system, often in carbon fibre. The induction sound becomes more audible and the response sharper.

The replacement filter is the simplest solution; the kit is aimed at those tuning their engine.

Looking after a washable filter

A cotton filter is cleaned and re-oiled, usually at the intervals when you would replace the paper filter, and more often on dusty roads. Use the kit from the filter's brand (K&N Power Kleen, BMC kit): cleaner, rinse with water, air-dry, then apply a sensible amount of oil.

Too much oil can foul the mass air flow sensor: let the oil soak into the cotton before refitting the filter.

Turbo engines: intercooler, charge pipe, inlet

• Intercooler: it cools the air compressed by the turbo. A larger core keeps the air cooler under repeated acceleration.
• Charge pipe and boost pipe: these rigid pipes replace the original ducting, often made of plastic, between the turbo and the engine.
• Turbo inlet and outlet: with a larger diameter, they reduce turbulence at the turbo's inlet and outlet.

These parts really come into their own with an ECU remap.

What gains can you expect?

On a standard engine, a sports filter mainly improves breathing and sound; the measurable gain depends on the model. An intake kit, an intercooler or a charge pipe deliver more on a turbo engine that has already been tuned. Manufacturers' stated figures appear on the product pages where available.

Another advantage of a washable filter: you no longer buy a disposable filter at every service.

Homologation in Switzerland

Intakes are among the parts that generally require a Swiss declaration of conformity for your vehicle, especially kits that replace the airbox. Where a certificate exists, it is supplied or offered at extra cost. If in doubt, see our Homologations page before ordering.

Original filters and servicing

Prefer to stick with original equipment? Paper air filters, oil filters and cabin filters from the major brands (MANN, Mahle, Bosch…) are in our service parts.