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Cold Air Intake (CAI) with Heat Shield

Warning: If you are not competent or do not feel comfortable doing any of these modifications or procedures, then please do not do so. I will not be held responsible for any damages caused by a result of your actions. Now on to the fun stuff!

So far this is one of my favorite changes I have made. It provides a little more top end power with out sacrificing much low end torque. Plus, it sounds incredible. It should work with any 6 cylinder engine that came in the e36. I'm working on a template for the heat shield.

Materials needed:
3" exhaust tubing
Two 3" hose clamps (Hardware store)
3" internal diameter rubber or silicone tubing at about 2-3" long
K&N 8" or 9" cone air filter (Summit Racing) (If you have ellipsoids you will need the 8")

1/4" by about 6" piece of metal
3" hose clamp (if you don't have welder access)

Heat shield
1/8" aluminum sheet (24" by 24")
PlastiDip (optional)

Tools Needed:
Drill with bits
Tin Snips
A really big hammer!
Bender or a muffler shop
Welder *

Remove the air box by removing the clips on the mass air flow meter.
There should also be two bolts holding the box in on the side closest to the driver side of the car.
Then remove the box by pushing it towards the rear of the car and then up.
You might have to loosed the snorkel towards the front of the box.
Once the box is out, remove the snorkel.

Start by getting the 3" tube bent to the appropriate angle. I did one myself with a manual bender and I had one done by an exhaust shop that used a hydraulic bender. I recommend having someone else do the bending, their experience is invaluable. The angle that needs to be made is about a 15-30 degrees from the horizontal.

Now, try it out on the car with the air box removed.

Hook the hosing on to the new piece that you had fabricated with a hose clamp. Now hook the other end to the air flow meter and secure it with another hose clamp.

Now connect the filter up to the other end of the tube. It should come with a clamp. The filter should point down and towards the corner of the engine compartment a little.

At this point, I had to do a little more bending on the original copy, but the final was modeled after it so the initial bending was just right.

On the final copy, I mounted the strip of metal from the bracket that holds the cruise control module to the air box originally. It was then bent towards the intake and removed for welding to the intake. On the original copy I used a hose clamp and an extra bend in the strip to secure it to the intake. (see picture below)

Next, I took it out of the car as a unit and cut all of the edges off of the tube that jutted into the filter to smooth the air flow. Give it some paint and allow it to dry. I painted mine with some PPG DP-90 and the finish has been incredible. This stuff really takes a beating and holds up great. Then hook everything back up and test it out.

Here's the same picture with some of the important parts labeled

Here are a few pictures of the original intake.

Heat Shield:
Here was the hardest part of the project. I used 3/16" thick aluminum which was very difficult to bend (think 3 ton car and a lift to get enough force). I recommend first making a cardboard template then cutting the aluminum out based on this template. Then testing it until you get it to fit just right. The idea is to block as much of the hot air coming from the fan and radiator as possible. So, you want to get it to touch the hood and down as far as possible. From the side of the radiator run it back towards the air flow sensor and make a 90 degree bend until you meet the shock tower. The pictures should help with this. Cut the hole for the intake in a drill initially, then remove more material with a grinder or something of the sort.

Here's the final product. The fabricated tube is not perfect as no one around me does mandrel bending on a case by case basis. The outside edges of the heat shield had a rubber trim piece put on them to clean it up a little. Then around the inner hole, I used a little PlastiDip to protect the tube from bumping the heat shield.

Here are some shots with it all installed in the car.

I plan on taking the heat shield out and painting the entire thing with a little DP-90 to give it a cleaner look. Possibly I will add some insulation to one or both sides of the heat shield.

The newest plan is to rebuild the entire heat shied with a thinner aluminum, spray it with DP-90 and then bake it for a little bit if I get the chance. Then put some insulation on the outside and re-spray it. Hopefully I'll pick up some better weather-stripping as I don't really care for this type. It does not look as professional as the ECIS shield.

Update [2.27.02]: I smoothed out all of the edges a whole lot and it looks much better. The lines are smoother and the surface of the shield is a bit smoother too. I filed the edges and rough spots on the heat shield. Then, I took a wire brush wheel mounted on a drill and went at it for awhile. Then cleaned it up with some soap and water, followed that up with some Wax and Grease Remover from PPG and shot it with 3 coats of PPG's DP-90. The final results look amazing. It's not perfectly smooth, but it didn't cost $350.

Here are a few pictures of the heat shield. I'll be adding a few with it all installed in the car.

You can really see how I had to wail on the thing to get it bent in these shots.

Update [03.11.02]: The whole intake system has been reinstalled in the car. I added weather stripping to the top and the portion that follows the curve of the engine compartment. It takes just under 4 feet to do these two sections. It looks MUCH better in my opinion. It really makes it look very professional. I'm working on a better way to fasten it to the car at this point. Pictures coming soon.

If you are interested in the weather stripping I used, email or IM me as I have about 20 feet left over.
I purchased it from JC Whitney after seaching nearly everywhere I could possibly think of, I found this. The perfect weather stripping for this application in my opinion.

JC Whitney Weather Stripping

Update [04.17.02]: Here are some shots of the heat shield with the new weather stripping.

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