How To---Handmade CAI and Heat Shield

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How To---Handmade CAI and Heat Shield

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Chevrolet >> Brand Review >> Intake, Headers and Exhaust >> How To---Handmade CAI and Heat Shield

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How To---Handmade CAI and Heat Shield - 3/24/2008 4:30:47 PM

rabbit0102030

Posts: 327
Joined: 4/3/2007
From: New Braunfels, TX
Status: offline

Want the benefits of a Cold-Air Intake (CAI) such as K&N's, AEM's, Air Raid's, et cetera, but don't have the cash to blow? Not too sure about a 'kit' off eBay? Want the satisfaction of using your hands (and tools) to create one of your own? These instructions will work for 1996 through end of production for Chevrolet Blazers, GMC Jimmys, and Oldsmobile Bravadas equipped with the 4.3 Vortec.

The following will show you how to make your own CAI, all for under $100; all with pretty common tools (and with a little help from a friend). There is no drilling required and you can return your vehicle to stock if you so wish with no signs of any modifications made! I will attempt to be as informative as possible, please feel free to reply or PM with any questions. I am by no means a professional mechanic, but that's the beauty of this modification-you don't need to be! Please read entire how-to if you intend on building one of your own as there are some different options you may choose that will affect appearance and/or price.

TOOLS NECESSARY:

Phillips head screwdriver
Flathead screwdriver
10mm wrench or 10mm deep-well socket and ratchet
Hammer
Sheet metal snips (I used 7" straight snips, you may have better luck with smaller but I did not want to cut FEET of sheet metal with anything smaller)
Needle nose pliers
Scissors
Utility knife
Work gloves (if you intend on cutting the sheet metal yourself)
Sharpie marker

TOOLS NICE TO HAVE IF YOU HAVE ACCESS:

Center punch
Drill with 1/4" metal bit
Sheet metal shear
Sheet metal bender
Band saw/pipe cutter/Sawzall
3.5" metal hole saw

SUPPLIES NEEDED:

The following supplies were purchased at my local hardware store:

Minimum 24" wide by 24" long sheet metal (I used 24" wide by 30" long just to be safe)
3/4" by 1/2" corner braces (or similar hardware)
3" High-heat capable rubber coupling (usually comes with hose clamps but just in case...)
Two 3" hose clamps
Two (or more if you prefer) each of machine screws, washers, and nuts (all in same or smaller diameter as holes punched)
One sheet metal screw (see Step 2 under "Installation of Heat Shield..." for size)
4-5 feet of 3/8" fuel line (or similar high-heat capable material, i.e. hood weather-stripping)
7-8 inches of 1/4" fuel line or washer fluid hose
1 can of high heat paint (your choice of color, there are links under "Conclusion" that show the difference between flat black and aluminum)
1 tube of RTV sealant (not necessary)

3" Mandrel-bent, 45 degree pipe (I got mine from a local performance garage)

Spare cardboard lying around (a case of beer box is large and rigid enough)

DISASSEMBLY OF STOCK AIR BOX:

1. Locate the four screws that hold the top of the air box in place.

2. Loosen (but don't remove) each one with a Phillips head screwdriver.

3. Locate and remove 10mm nut on right side of air box (it's a good idea to put it back on the stud once you remove the air box as you will be re-using this).

4. Unscrew hose clamp with flat head screwdriver and remove (you will not re-use this, but hold on to it in case you decide to return to stock).

5. Place one hand on each intake pipe, lift and separate (video).

6. Grip the back of the air box, lift off the mounting stud and pull forward, then pull up and off mounting bracket connected to core support (video).

7. Looking at the core support from the cabin side you will see the mounting bracket. Grip the top tab, gently bring it towards yourself, and lift, sliding the bracket up and out.

8. You will be left with the stock air inlet on the left, and the hole where the bracket slid into on the right.

FABRICATING HEAT SHIELD:

1. Use the cardboard to make a template of the heat shield. Be sure to follow all stock contours of surrounding engine bay, as well as under hood.

2. Trace this pattern onto your sheet metal with a Sharpie marker.

3. Use your metal snips to begin cutting on the lines you just traced. Work your way around and remember that sheet metal is not all that forgiving. If you have access to a sheet metal shear, I would recommend using it for the outside cuts.

4. If you only have the necessary tools, use your Phillips head screwdriver and a hammer to punch some holes where your intake pipe hole is. If you have access to better tools, use the center punch and hole-saw to make this hole and skip to STEP 8.

5. Use your snips to cut between the holes you just made to gain a starting point to cut the circle.

6. Once you have a starting point, cut the sheet metal into pie-shaped pieces.

7. Lift each piece with needle nose pliers and cut, one at a time.

8. Once again, if you only have the necessary tools, use your Phillips head screwdriver and hammer to punch two more holes, one to match the stock air box mount, and the other to match the core support mount (not shown, you will need to mark it on your template). You can also use a drill with 1/4" metal drill bit to make these holes.

9. You will need a hard, straight surface to hold the sheet metal against while you bend it. If you have access to a sheet metal bender or brake, by all means use it!

10. TEST FIT, TEST FIT, TEST FIT! The only way to be sure it will fit just right is to test it frequently. Be sure you have all the right angles for your bends!

11. Open your corner braces (or similar hardware) and mount them to the holes you punched in Step 8 with the machine screws, washers, and nuts.

HEAT SHIELD TRIM AND APPEARANCE:

1. Cut your 1/4" fuel line or washer fluid line with scissors down the middle from end to end. You can use a utility knife but I found that scissors were more accurate.

2. Install the hose in pipe hole cut in "Fabricating Heat Shield" Steps 4-7 for proper fit.

3. Repeat this process for the top and side trim using the 3/8" fuel line or weather-stripping. Once again, I used my sheet metal snips because they were more accurate than a utility knife.

4. The pipe I bought was too long. I was able to take it to a friend to have about 2.5 to 3 inches cut off of the NON-FLANGED end. If you have access to a band saw, Sawzall, or pipe cutter large enough, you can use them as well. Take your mandrel-bent pipe to a well-ventilated area and spray it with your high heat paint. You may choose to scuff up the surface before painting, but it is not necessary. Remove all trim from the heat shield and paint this as well. Remember, a few light coats are better than one heavy coat!

5. Allow paint to dry as per instructions on can. Reinstall all trim. You may use RTV silicone sealant to 'glue' the trim to the sheet metal, but the rigidity of the fuel line/washer fluid hose was enough to keep it in place.

INSTALLATION OF HEAT SHIELD AND INTAKE PIPE:

1. Drop the shield into your engine bay, being mindful of the air box mount stud. Be sure to line up your bracket with this stud. Don't forget to take that 10mm nut off if you stored it there earlier!

2. Line up your core support bracket with the hole already in the core support and screw it in. I can't quite remember the size or thread of this screw, I just grabbed a bunch that looked about the right size and tried each one until it fit.

3. Put the 10mm nut back on the stud after the shield has been installed and tighten it down.

4. You will need to cut your 3" coupling in half. Once again, you can use a utility knife, but I found that my snips gave me a straighter cut (sorry I don't have a picture of this, I just used the other half from an intake previously made). Attach this coupling to the intake pipe coming from the throttle body and tighten the hose clamp for THAT SIDE ONLY!

5. Break out your air filter. As stated, the one I purchased was on sale at my local auto parts store for under $20. If you would like to splurge, feel free to buy a K&N or like filter of similar size. You can basically use any filter that will fit.

6. Insert NON-FLANGED end into filter, slide hose clamp so that you can tighten it from the top, and tighten screw.

7. Gently place filter/pipe combination setup into heat shield area. Tilt the pipe back towards the hole in heat shield and connect it with the rubber coupling already attached to upper intake pipe coming from the throttle body.

8. Tighten remaining hose clamp on rubber coupling once lower intake pipe is installed, and....

9. Voil�!

CONCLUSION:

There you have it! Plan on taking about a day from start to finish on this bad boy once you have all the supplies. I'm sure some of you can find supplies cheaper than I did, and some of you may have access to better tools. I will be honest and say that this is my second time around. After making my own, my old neighbor with a 2001 Bravada was intrigued at not spending over $100 for an intake. Now granted, this does not replace the upper intake hose from the throttle body to the air box, but for the money and being able to make this yourself, you can't beat it!

I did not dyno my truck either before or after the installation of the new heat shield and intake pipe so I can not give you HP numbers. I will repeat what I said in another post about my expectations for this setup. I did this merely to let my engine breathe better and gain some gas mileage out of it. After running through two full tanks, I have noted a +2mpg gain over stock. Another nice aspect of this is the sound gained at wide-open throttle (WOT). I have also noticed a quicker throttle response while merging onto highways.

Being the second time around, this one looks a whole lot better than my first, which is unfortunately installed in my own truck. It's still functional of course, just not as flashy!

Like I said, feel free to reply and/or PM me with any questions or comments! I'd love to hear them!

PRICE LIST:

Sheet metal: 2.5 feet @ $2.49 a foot = $6.23
Corner braces: $1.99
Rubber coupling with hose clamps: $5.99
Machined screws, washers, nuts: 6 @ .10 a piece = $0.60
3/8" Fuel line: 4-5 feet @ $1.29 a foot = $5.16-$6.45
1/4" Fuel line or washer hose: 7-8 inches @ $0.99 a foot = $0.58-$0.66
High heat paint: 1 can @ $3.99
Mandrel-bent 45 pipe: $20.00 cash
APC filter from Advance Auto: On sale for $19.82, originally $24.94
(I did not include the RTV sealant as it is completely optional)

TOTAL:

If you decide to err on the side of surplus, your cost will be $70.85. If you get the minimum, and happen to find a filter on sale, your cost will be $63.11. Of course, this is assuming you already own the necessary tools stated in the beginning of the How-To.

**This was written, and hand built by TripleBlackBlazer from BlazerForum.com**

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