air

An effective and not expensive
possibility to increase the power
of your engine is the use of
professional air filters.

Every engine needs air, not only to
cool the engine, but also for the perfect mixture between
fuel and air. As you can see in the drawing below open air
                                                               filters dramatically
                                                               reduces the intake
                                                               restriction as it
                                                               smoothes and
                                                               straightens air flow
                                                                compared with
                                                                standard OEM filters,
                                                                made of paper and
                                                                closed in housings.
                                                                More air means more
                                                                usable power and torque, especially at turbo charged engines that need many air in a short time when the turbo runs at full boost.

Basically their are two types of filter: The replacement filters, that replace the standard OEM filters in the air filter housing (see color picture). The Other type is the open air
filter, which replaces the whole air filter housing (see drawing).    A replacement filter can gain +2-4% more hp (price $40 - $80), where as an open air filter can gain +20hp ($100 - $300). The open air filter are more attractive, but in most countries in Europe not officially allowed. They should only be used for the motorsport, but it clear that they can found in many regular street cars.

For more information about airfilters click here.

to "start" with the replacement filter and see what is happening. After gaining some tuner information at a local car exhibition, I called one of the tuners to order a Filer for a Golf IV TDI. As the filter was on stock, I received it within 3 days. The Filter was packed like shown on top, in a big paper box, containing the filter, a rubber belt, glue and an operating instruction. Ofcourse I was very curious to see if it was possible to exchange the filter myself. To my surprise it was even simpler as described !
I only had to disconnect the air intake sensor on the tube between engine and air housing (just "snap" out), releasing two screws of the housing and it is possible to open the housing and remove the standard PAPER filter. The removed filter is THREE times thicker and higher as the K&N Filter. I needed the glue to mount the rubber belt on the upper part of the housing, so that the housing and filter are closed well together. After about 15 Minutes I was ready to go for my first drive with this filter.

K&N claims up to 40% more air and 2-4% more power with replacement filters. I must say the effect is better as I expected. The positive changes are:
- No Turbo delay (turbo"lag") anymore
- Better acceleration at higher RPM's (> 3000 rpm)
- Smoother and quicker response on the throttle

Conclusion:
As standard PAPER filter delivers the TUNED engine not enough air at once, it creates a turbo "lag". This can be solved by installing an professional (mostly OIL) filter (in my case an K&N), which allows almost a free flow of air.

If you have questions, you can e-mail me.