Pelican Technical Article: Cold Air Intake Installation Wayne R. Dempsey
Time: 8 hrs
Tab: $400
Talent:
Tools:
Torx anti-tamper screwdriver
Applicable Models:
986 Boxster (1997-04) 987 Boxster (2005-08)
Parts Required:
Cold air intake kit
Hot Tip:
Plan for this to take longer than you expected
Performance Gain:
Freer breathing engine
Complementary Modification:
DME Software upgrade
This article is one in a series that have been released in conjunction with Wayne's new book, 101 Performance Projects for Your Porsche Boxster. The book contains 312 pages of full color projects detailing everything from performance mods to changing your brake pads. With more than 950+ full-color glossy photos accompanying extensive step-by-step procedures, this book is required reading in any Boxster owner's collection. The book is currently available and in stock now. See The Official Book Website for more details.
Check out some other sample projects from the book:
There's been a lot of talk on Internet chat boards lately about cold air intake (CAI) systems. Some manufacturers will swear up and down that there's hidden horsepower in the intake system. Other experts' claim that it's total bunk: a myth that has easily circulated in the age of the Internet. I personally believe that the truth is located somewhere in-between. On some models, a properly engineered cold air intake kit can effectively cool the intake charge entering into the cylinders. Why do you want this in the first place? Cooler, denser air will further decrease engine detonation, and will also deliver a denser air charge which theoretically corresponds to an increase in horsepower.
First of all, the stock Boxster intake system is indeed already a cold air intake system. It sucks air from the outside and insulates this intake from the heat generated by the engine. Where it doesn't work too well is in the area of airflow restriction. The stock system is somewhat restrictive, and makes the air work its way around in order to enter the engine. Aftermarket performance intakes serve two purposes: to better inject colder air directly into the intake system, and also to reduce the restrictions that are inherent in the stock system.
Just how much horsepower can you expect to gain? It all depends on which model kit you use. It is possible that a poorly designed kit used with an aftermarket air filter will actually create more restriction in the intake, and cause a decrease in horsepower. In addition, a poorly installed intake system with leaks will also decrease performance. I have seen dyno tests where the installation of an intake system has done nothing, or has even reduced horsepower. Then again, I have seen other tests where significant gains of about 10 HP were recorded.
The bottom line is that a performance intake system is a (typically) expensive aftermarket add-on that may increase your horsepower only slightly. Some kits cost over $500, which translates into a very high dollar per horsepower ratio. Some other kits are less expensive, and incorporate reusable aftermarket filters. While I'm not a huge fan of these filters as then tend to filter less than the stock ones (see Pelican Technical Article: Air Filter / Pollen Filter Replacement), there can be some costs savings in the long run from not having to buy multiple stock air filters.
Perhaps the only thing that most people agree on is that a performance intake system will often give you a much better engine growl at higher revs. I'm personally a huge fan of growling noises, so this would certainly be a plus for me if I were making the decision to install one of these systems. For those of you who prefer a quieter engine, you might be slightly annoyed at the new music your engine is playing.
There are literally hundreds of manufacturers of these products, from the large tuning companies to people selling homemade kits on eBay. If you are going to install one of these on your car, I would do your research first, and stick with a well-known manufacturer. For this project, I decided to install the intake system manufactured by well-known and reputable Evolution Motorsports. It replaces the stock air cleaner with a high flow cone filter and a special tube to house the mass air flow sensor (MAF). The result is a freer flowing intake with no headaches caused by check engine lights (CEL). The air intake housing is sealed off from the engine compartment and is designed to only funnel airflow from outside the car into the intake system. It was also a very good choice for installation with the 3.4 engine upgrade (see Pelican Technical Article: Boxster Engine Conversion Project).
The installation of the system is not as easy as you would think: plan to spend an entire day wrestling with getting the old intake out and the new one in. Follow the photo array in this article for details on the installation for Boxsters up through 2004.
Figure 1
Here's the EVO Fresh Air Induction System for the Porsche Boxster as supplied by Evolution Motorsports. The kit consists of a housing that is molded from crosslink polyethylene which has a very low thermal conductivity to keep engine compartment heat away from the cold air side of the intake. The reusable cone filter is freer flowing than the original stock filter. The MAF intake tube is manufactured to OEM diameter specifications to avoid check engine light problems (CEL).
The first step is to remove the left side fresh air grill. A single screw (yellow arrow) attaches the grill in place, along with a set of plastic snaps. Use a plastic spatula to carefully work around the outside of the grille and pry it out of the clips. Remove the air intake snorkel by pushing it up and down and then out towards you. It is on tight and will require some force to remove.
Carefully remove the mass air flow sensor (MAF) using a T20 tamper-proof torx driver and install it into the new metal tube provided in the kit while the tube is on your workbench. Handle the sensor with care and make sure that no dirt gets into it as you are moving it around. The sensor requires a tamper-proof torx screwdriver to remove, which EVO provides in the kit. It's also a good time to clean the MAF (see Pelican Technical Article: Troubleshooting and Replacing the Mass Air Flow Sensor (MAF)).
Disconnect the two clamps (one at each end) that hold the stock air intake tube to the throttle body (green arrow). Remove this c-shaped tube from the car and put it off to the side.
Loosen the clamps at the top of the intake manifold. The next few steps are required in order to gain enough access to remove the really large stock air intake box. Also disconnect the 10mm nut that mounts down the throttle body housing (see Project 83: Starter Replacement for a photo of this nut).
Loosen the intake manifold screws. You will need a Torx socket set for these. Also remove the vacuum hose right-angle connection from the manifold (yellow arrow). You will be lifting up the intake manifold slightly in order to gain access to remove the stock air box.
Now it's time to detach the stock air box. There are three bolts that attach the assembly to the car. Two can be accessed from the top of the car, the third must be removed from below (you need to jack up the car: see Pelican Technical Article: Jacking Up and Lifting the Boxster on Jack Stands). With the air box loose, it's time to remove it from the car. Have an assistant pull the intake manifold towards the left side of the car, in order to give you the room you need to pull out the air box. Removing it by pulling out the MAF tube first is easiest way to get it out. This is by far the most difficult and frustrating part of the installation and the removal of the air box will require quite a bit of wiggling and quite a bit of force to remove from the car.
Installation of the new fresh air box is a snap. Simply install it into the car where the old air box was located. Insert the MAF pipe, and then install the top bracket in place.
Clamp the cone filter onto the end of the MAF pipe. Install the OEM air intake tube that you removed previously (yellow arrow). With the new air intake in place, reassemble the intake manifold, taking care to reconnect any vacuum lines you may have disconnected.
Comments: how do the clips hold the fresh air grill on to the car? i cant seem to get the grill off and i dont want to break it. thanks
October 29, 2011
Followup from the Pelican Staff: I'm assuming you're talking about the grille on the outside of the car? There is a screw that holds it in and then two clips that are difficult to get to. Not going to lie here - I broke both of mine getting them out when working on the car. I don't think new ones are that expensive though ($15 each?) - Wayne at Pelican Parts
monaco
Comments: I noticed that all the cold air intakes are only behind the driver's door. What is the air intake behind the passenger's door for? Would it be possible to do a 'dual' cold air intake by getting a y connector and installing one behind each door? Would this improve anything? Would this mess up the air intake sensor? Thanks.
August 6, 2011
Followup from the Pelican Staff: The intake on the right side of the car is used to let fresh air into the engine compartment. There is an electric fan there that is controlled by a thermostatic switch. When the temperature in the engine compartment gets too hot, the fan turns on. I suppose that you could design some wacky dual-intake setup to funnel air into the engine, but on the Boxster, the air intake really isn't a huge restriction on the engine. You probably wouldn't gain very much horsepower from this. Creative thinking though! - Wayne at Pelican Parts
Check out some other sample projects from the book:
