of the most popular upgrades out there today is to install a cold air kit or
cone filter on your car. The benefits of this include a small horsepower
increase and a really nice growl when you accelerate. In this tech article
we will discuss the installation of a cone filter on the BMW E30 3 Series.
In this case we are using my 325is for the installation, however this
article applies to all BMW models in general. I am using a K&N cone
filter assembly for this installation. K&N filters are a great upgrade
for your car. They allow more air to flow through the filter than the stock
unit and are designed to be cleaned and re-used rather than the stock
filter, which you use once and throw away. K&N filters use an oil
filtration design, which means that you oil the filter, and particles of
dirt and grime get caught in the oil. When you have to clean the filter, you
simply clean out all the old oil, then re-oil the filter.
this case the filter comes already pre-oiled, so all we have to do to it is
put it on. The first step is to locate the stock air box in the front of the
car on the driverís side. First, you will want to loosen the hose clamp on
the back of the airflow meter, shown here. Once loose, carefully remove the
rubber intake boot from the airflow meter. Next, find the electrical
connector on the airflow meter, press the metal clip in and pull the
remove the two 10mm nuts securing the air box to the bracket shown here.
Once removed, slowly lift out the air box to the rear. You will now see a
small tube in the front of the air box. This is the snorkel that takes
incoming air from in between the headlights. Carefully disconnect this
snorkel from the air box then lift the whole air box assembly out of the
the air box out of the car, undo the metal clips around the air box and
remove the upper portion that the airflow meter is connected to. We will
have to remove the airflow meter from this piece to continue. With the upper
portion removed, you will now see a baffle inside the filter. Remove this
baffle and you will see four 10mm nuts that hold the airflow meter to the
air box. Remove these nuts. The airflow meter will now be free of the air
box. Be sure that you also remove the small gasket in between.
find the adapter piece that is included in the cold air kit. We will need
this piece so that we can mount the cone filter directly to the airflow
meter. Simply place the gasket over the studs on the airflow meter, and then
place the adapter piece over the gasket. Re-install the four 10mm nuts and
tighten. The final result will look like this.
go back to the car and place the airflow meter back into the intake boot and
tighten the hose clamp, securing it in place. Re-connect the electrical
connector on top by pushing it on while holding the metal clip in.
the cone filter, and place the included hose clamp around the outside of the
rubber lip on the back. Now slide the cone filter over the adapter piece on
the airflow meter and tighten the hose clamp.
we need to secure the filter assembly to the bracket that once held the air
box. I simply used two zip-ties threaded together in a loop around this
bracket to hold it in place. Tighten the zip ties and cut off the remaining
we will also need to secure the cruise control actuator as shown here. With
the air box removed, the stud that once held the actuator is missing and the
actuator is only held at the bottom. Simply use a small 10mm bolt, slide it
through the bracket, and then re-install the 10mm nut on the other end. This
will secure the actuator.
This shows this final
And thatís it, youíre
Just another note, the
cold air kit does not include a heat shield. The purpose of a heat shield is
to deflect the hot air from the radiator from entering the filter. I am
currently in the process of developing a heat shield for the filter using
sheet aluminum and portions of dryer ventilation. I will have my results
installation, I noticed the results immediately. Through the midrange, the
car pulls harder, and Iíve noticed that the car runs slightly cooler as
well. Sound wise, it really makes a difference. Before the installation, the
intake noise was very quiet and subdued. Now, there is a loud growl coming
from the engine when you step on the gas.
Well, there you have it - it's
really not too difficult at all. If you would like
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