FWD Tech Guides '95-'07 Guides/How-To information for FWD Montes 1995-2007

Mod Guide: Build your own Cold air intake (guide)

Old 10-22-2016, 02:18 AM
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Default Build your own Cold air intake (guide)

Hey all.

I decided to do a project to build my own cold air intake after buying an aftermarket intake that was pretty cheap but took in air from the engine bay. Sorry though I seemed to have lost the first half of the images I took.

You can find what I do have in my imgur album here -> CAI - Album on Imgur

Basically you will need

2 sheets of Aluminum 2' x 1' from home depot
1 sheet of plexiglass 11x14 (a bit bigger would be better)
Utility knife
Tin snips
Sheet Metal Bending Brake -got mine the large one from harbor freight
Radiant barrier (optional)
1/2" Foam weatherstrip insulation
Duct tape
JB Weld

Total cost is about $150 if starting from scratch, the metal brake and ebay air inatke was the most expensive parts (about $40 each). If you have the tools, and air intake then the cost of materials will be about $60.

General steps
1-Remove air intake, unplug MAF sensor and tie down PCM tray using zip ties. Remove structural support bar too.

2-Measured out the shape of the area you want for the cold air intake (CAI) I did this using cardboard, measuring tape, and taping the cardboard in the position I wanted.

3-Next I bent metal into 2 L shapes that would overlap, leaving the front and one side exposed. These sides will face the original air intake and the sidewall away from the engine.

4-Then I bent the top metal to form a ledge that my plexiglass top will sit on. I did a more complex 2 bend ledge and forced the second bend into a inverted U shape. If you make it a simple inverted L then you can just tape/adhere/drill a hole and tie down/fasten the plexiglass to the top of it.
**this was probably the hardest part**. You can see my seam in the first image, note the duct tape on it.

5-Next I placed the 2 metal halves on one another and held it with duct tape. I then placed it in position, cut metal as needed, and adjusted duct tape bonding as needed. Then I used JB weld to adhere the metal together and clamped it down to bond overnight.

DAY 2 (see IMGUR album)

6- Place duct tape over seams, make sure JB weld had no gaps, the duct tape should also prevent hot engine air coming in. Then cut plexiglass to fit into the CAI's ledges (ALBUM IMAGE 1)

7- Next I used the box cutter to pierce the end where the EBAY'd hot air intake 4" elbow ill fit into. Then I used pliers and the tin snips to widen the hole.

8- Test fit elbow to see if it goes into the hole with no issues, if not widen the hole, but not too much. Repeat as needed. I made it a bit wider than the elbow. Maybe 1/4" and placed some weather stripping foam in it, sticky side on the metal ledge and put some duct tape to better secure it in place. (album image 3)

9- Line inside with Radiant barrier. Leave a bit extra in the front and sides overhanging. You will use some to prevent air inflow fromt he engine and you can TRIM this later if needed. I did 2 layers of the radiant barrier, using duct tape O shapes, or you could use an adhesive (probably easier) (ALBUM IMAGE 2). You can see the ledges i made a bit better in this pic. I cut the radiant barrier with some slits think X and + to also help prevent any air flow going in. (IMAGE 3-6)

10- Place in engine bay and hook up ebay air intake. Add weather stripping on top of ledge (IMAGE 9)

11- Cut corner out of intake for MAF sensor wire to fit. See IMAGE 10

12-Reattach support. Use ductape to seal any gaps between the air intake and engine compartment (notice 1 bit on the side isn't flush). Add bit of weather stripping by MAF sensor wire. I also used some to help hold the plexiglass to the foam for a better seals where needed. (you can use duct tape if you want). See IMAGE 11 (top view), IMAGE 12 (engine to CAI), and IMAGE 13 (front of CAI)

You are done. Tape as needed though mine was flush against the front and was near/touching the radiator coolant hose, may want to space it better or add some extra barrier on the inside/outside or use foam to prevent conduction.

It took me I think 2 weekends, doing a bit each day. Was fun, maybe not as practical as store bought CAI after adding everything up but I think mine is better insulated and I have 2 sources of cold air. The first from the original front intake and the second from the sidewall.

Hope you fond this helpful/interesting

Last edited by The_Maniac; 10-29-2016 at 09:55 AM.
Old 10-22-2016, 09:32 AM
Join Date: Oct 2016
Posts: 333

Cool guide; I'm glad you like it!

I don't typically do any performance upgrades and drive my cars usually pretty stock.
Old 10-22-2016, 04:54 PM
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Thanks for taking the time to document and post your project!!

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