BMW E85 Z4 Cold Air Intake Installation

Photo of installed cold intake

By Dan Jones

Many members of the BMW Car Club of America New Mexico Chapter enjoy personalizing their BMWs including performance enhancements that are considered “Do It Yourself”. One such DIY modification is adding a Cold Air Intake (CAI) system.

BMW has done an excellent job in developing the original air intakes to be as quiet, yet nonrestrictive, as possible. However, cost constraints as well as overall noise and comfort requirements can make the factory intakes less than ideal from a performance standpoint.

Aftermarket cold air intakes provide a less restrictive filter and piping that increases the volume of air inducted by the engine. This allows fuel to burn more efficiently, due to the increased rate of oxygen combustion and may result in increased horsepower. While some manufacturers claim increases of 5 to 20 horsepower with a cold air intake, the reality is there is a modest increase in power, but there is an improvement in overall throttle response. The biggest difference you will notice with the addition of a cold air intake is the induction noise becomes more audible since performance intakes have no sound baffling.

There are several manufactures of cold air intakes for BMW Zs. Examples include aFe Power with a collection of well-known cold air intake systems, GruppeM Carbon Fiber Ram Intakes, Eventuri Carbon Intakes, Racing Dynamics intake systems, AEM cold air intake systems and DINAN has a simple high flow intake for early E85 Z4s that replaces just the top of the stock air box. Most of these are available from a variety of sources and it pays to shop, but be careful with fitment – make sure it is appropriate for your specific car!

Installation of an aftermarket cold air intake system in your BMW is typically DIY. The following is a step-by-step installation of an aFe Magnum FORCE Stage-2 Pro 5R Cold Air Intake System (P/N: 54-11602) on a 2006 BMW E85 Z4 3.0si: (click on any image to enlarge)


Photo of clamp
After disconnecting the battery, disconnect MAF sensor and loosen clamp on stock air box.


Photo of stock air box bottom
Unlatch top of stock airbox, lift up and pull upper half of air box out. Remove air filter. (Note the two rubber grommets that hold down the lower air box.)


Photo of air box removal
Lift and pull bottom half of air box out of the vehicle. Don’t over-think this. You just need to pull it hard enough to free the rubber grommets from the mounting posts.


Photo of loosening clamp
Loosen clamp on back of intake tube attached to smog pump.


Photo of removing intake tube
Loosen clamp on Throttle Body and remove intake tube out of vehicle.


Photo of intake tube cavity.
The stock intake tube and air box has now been removed. Will begin preparing for installation of the cold air intake system.


Photo of air box support clips.
Turn and remove both air box support clips from vehicle.


Photo of support clip.
To remove support clips, insert small screw driver and pry up the half-ring. The clip will now turn and allow extraction. (The post is BMW part number 13717543174 in case it breaks.)


Photo of area ready for new installation
Ready for installation of the cold air intake system.


Photo of new intake tube.
Carefully remove MAF sensor from the stock intake tube and install on new intake tube. Make sure arrow is in direction towards Throttle Body. Attach tube to outside of new air box housing.


photo of crankcase filter
Attach crankcase filter to smog pump and tighten clamp.


Photo of new housing
Place new housing into vehicle and secure using nuts and bolts through the support clip holes. (Cardboard shown prevents lost nuts and washers.)


Photo of coupler clamps
After attaching coupler to intake tube and throttle body, tighten clamps.


Photo of air filter
Install air filter element on intake tube and tighten clamp.


Photo of housing cover
Install cover on housing.


Photo of MAF connector
Connect the MAF sensor and reconnect battery.


Photo of CAI
Installation complete!