DIY: Fabricating a Splash and Heat Shield for your intake.

This is a write up of how I fabricated a splash and heat shield for the Rusty's Intake Tube on my 2000 Cherokee. Tell me what you think. -Steve

Rusty’s Intake Splash Guard and Heat Shield
1998 – 2001 Jeep Cherokee

Overview
I recently installed a Rusty’s Air Tube and AEM “DryFlow” air filter element on my 2000 Jeep Cherokee Classic. I was very happy with the ease of installation of these items and satisfied with the performance, albeit minor, gains I noticed from these intake modifications. I have to say the real reason I purchase the AEM “DryFlow” cone filter was mainly for the ease of maintenance, soap and water cleaning and no oiling but of course the increased flow is a plus. This intake setup combined with the Edge Trail Jammer Kit (a 62mm Throttle Body and Power Programmer) and a Rusty’s Flowmaster 50 Series Cat-Back Exhaust, give the 4.0L a nice mellow rumble and much improved throttle response. The programmer shines at wide open throttle helping to progress the HP and torque curves. Without the programmer and just the intake and throttle body installed the 4.0L loses its grunt and runs a little flat through the upper RPM range.

The Problem
After reviewing the design of other air intake systems for the Jeep Cherokee and TJ, I became concerned about the open air nature of my new setup.
(Picture of intake without shield)

It seemed that the position and design of my new intake setup put the filter element in a position particularly vulnerable to water and dirt being splashed on it during wet on and off road driving. I decided I would attempt to fabricate a splash guard to protect as much of the filter element as possible in hopes of maintaining a free flowing design but keeping as much unnecessary dirt and water off the filter element as possible.

The following is instruction on how I fabricated a (actually 2) splash guard for 1998-2001 Jeep Cherokees with a Rusty’s intake tube and open hi-flow air filter element.

NOTE and Release Notice: This splash guard was fabricated for a 2000 Jeep Cherokee with a previously installed Rusty’s intake tube and a 9 inch AEM “DryFlow” air filter element. This design should work on all 98’-01’ Cherokees with a variety of brand name 9 inch or shorter cone style air filters. A variation of this design may or may not work on earlier model Jeep Cherokees. This tutorial is a write up of my personal experience. Your experience or situation may vary greatly from mine and by using this write-up you consent not to hold me liable for any personal injury or damage that may occur to you or your vehicle before, during or after the fabrication and installation of this modification.

List of Tools
(Picture of Tools)

List of Materials
You will need a single piece of sheet metal that is 22ga or thicker and at least 32x24. It would be a good idea to buy at least 24 inches of 1/8x3/4 inch or thicker strap metal to make some support brackets to help stiffen the shield. You will also need some 1/4x20 or larger screws, nuts and washers (4 each). Some edge trim or seal to finish off the top edge of your shield if you like and a can of your favorite color of spray paint, I chose clear because I liked the shiny metal look.

Description
Step 1: Template Creation
The first step is to create a template for your shield out of cardboard. I used a USPS Priority mail box and it worked great but any piece of relatively stiff cardboard will work. Gift boxes or poster board may work even better than corrugated cardboard because they will be easier to cut and bend. Be sure to mark and cut the holes as well.
(Picture of Template)

Step 2: Test Fit
Once your cardboard template is cut, fold and shape it into the relative shield shape. See Picture.
(Picture of Folded Template)

Note that there are only two mounting positions and that two of the tabs and corresponding holes will be overlapped and bolted in postion with one bolt. NOTE: No holes need to be drilled in your Jeep because the shiled is held in place by the two 5/16 bolts and the welded nuts that held in the stock air box. Now, position the template in the engine compartment with the air filter installed and see how it fits. You may need to trim your template to obtain proper clearance around your air filter. This may require several trimmings and test fittings to get it right. Be sure to always line up the two mounting holes while test fitting.

Step 3: Measure Twice Cut Once
Once you are satisfied with the fit of your template lay it flat on your piece of sheet metal and use your sharpie to trace the outline of your template on the metal, including the mounting hole positions. Next, cut the sheet metal to match your template. I used a $30 Air Nibbler form Harbor Freight and it made quick work of this task. I would think a cutoff wheel, or heavy duty tin snips could do the job though the curves may be tricky with the cut off wheel and the snips may distort the metal. Of course a scroll or jig saw with metal blade could always work as well.

Step 4: Drill, Grind, Bend and Test Fit
Now that your sheet is cut it is time to drill the three 5/16 holes in their appropriate mounting locations. I also decided to use a bench grinder with wire wheel to round of the edges of my shield and to remove any sharp edges and give it a more finished look. Next, bend the metal to match the bends in your template. GO SLOW! Get your bends right. You may be able to do this by hand but used a bench vise, rubber mallet and some scrap wood. Once you have the shield bent up test fit it with the air filter element installed to make sure you like the way it fits.

Step 4: Fabricate the Braces
You may be able to use your new shield as is but I wanted a little more support for mine. You will now use your piece of 1/8” strap metal to fabricate a couple of braces. Measure the short mounting side of your shield through your mounting holes and add this length to the long height side of your shield. Cut 2 pieces of strap metal that match these two total lengths. Should be somewhere in the neighborhood of 12-15 inches each. A hack saw or cut off wheel will make quick work of cutting the strap metal. I again used my bench grinder to round and smooth the edges of the strap metal. Now you will bend the strap metal in the right location to create an “L” type brackets. Measure the short mounting side of the shield through the mounting hole and mark this length from one end on the length of strap you cut. Repeat for the other mounting hole and piece of strap. Once both pieces are marked bend a 90 degree angle or “L” into each at the marks you made.

Step 5: Mounting the Braces
Line up your pieces of bent strap to the inside of your shield and mark the 5/16” mounting holes on the strap through the holes in your shield. Next mark 2 mounting holes evenly spaced on the long ends of each piece of strap in the position of your choosing. Drill two 5/16” holes for the mounting holes on the short ends where you marked and four 1/4” holes for the long end marks. It would be best at this point to test fit your shield again with “L” braces in place. Once firmly bolted in place mark the four upper 1/4” hole locations on the shield through the mounted bracket. Remove the shield and drill the upper holes you marked in it. Mount the braces to the shield with four 1/4” sheet metal screws and nylock nuts with a washer on each side of the shield.

Step 6: Final Fit and Finish
You may or may not choose to do a final test fit before finishing your shield. Once everything was mounted together, I decided I wanted to put a finish on my shield to protect it from corrosion. I like the industrial look so I just decided to clear coat mine with high temp enamel. I don’t think high temp is necessary but a little overkill never hurt and the can was lying around anyway.
(Picture hanging)

(Picture Final Look)

Once dry, I also decided to add some black door molding from PepBoys to the top edge of the shield to protect the filter from any possible abrasion and give the shield an even more finished look.
Install for last time.
(Insert Final Install Picture)

Results
I am happy with how the shield turned out. It is in no way water or air tight but it was only ever conceived to deflect water and debris. Only time will tell if it really serves its purpose but for now it gives me a little added piece of mind and also gives my new intake a more manufactured look.

Impressions
After completing the fabrication and installation of my new splash shield I realized that a slightly larger piece of sheet metal could have provided any even better degree of coverage and protection. I may purchase a larger piece and create a full coverage shield in the future.

[b]UPDATE

Since I originally fabricated and installed this splash shield I decided to take a second stab at the design increasing the size and quality of the shield. I purchased a much larger and thicker piece of sheet metal, some heavier duty strap metal as well as some heavy duty Trim-Lok edge seal. I also decided to use stainless fasteners for my brackets and bought a cheap electric metal shear from harbor freight. The metal shear made cutting straight and curved cuts in the heavier gauge sheet metal a breeze, it also provided smoother cuts.

NOTE: if you need a small or large amount of any type of metal go to a metal liquidator like the one on Old Airport Road in New Castle, DE. I got a much larger piece of heavier gauge sheet metal and a much longer heavier gauge piece of strap metal for about a third of what I paid for just the piece of sheet metal at Home Depot the first time around.

I pretty much used the same procedure as the first shield creating a template out of cardboard and using a trial and error test fit procedure, I just didn't photograph it all this time. This time around I took the time to enclose the filter as much as possible which required bending the Rusty’s Air Tube bracket to position the intake tube and filter properly. I also cut the top edge of the shield to align with the body and hood dimensions so the 3/4 inch Trim-Lok edge seal I added seals up against the bottom of the hood. To top it all off I took the unfinished shield to Powder Barons in Middletown, DE to have them coat my shield in a textured black for a truly professional quality finish. I might note that Mark at Powder Barons gave me an excellent price for the coating and I will be taking parts back to him in the future.

Here are some pictures of the unfinished and finished shield. Now, I can finally call this project complete.

Quote from Wolverine

Kind of defeats the purpose of a cone filter if you fill it all around with metal. I understand a splash guard but you built a box. Should have just kept your stock air filter in my opinion.

It's not really a box, it is pretty much the same design as the AEM Brute Force, K&N FIPK and AFE cold air intakes. If you look closely you will see there are two 3 inch holes cut in the panel at the front of the shield (closest to the driver side headlight). This is the location of the stock airbox inlet. The filter can gather cold or should I say colder air coming in from around the headlamp and gap between the radiator and headlamp housing. These two holes are each almost twice as large as the hole in the factory airbox and in the same location. The other issue is that the stock panel filter is more restrictive than the AEM filter with less surface area and it is washable and reusable without oiling.

I did reinstall the factory airbox with all other mods listed in the write up. The stock box had a basic fram air filter in it and there was a noticeable decrease in throttle response and torque.
I also had the unfinished new shield installed for a couple of days without the 2 three inch holes cut in it and performed more closely to the stock air box setup but still not as bad.

It should be noted that AEM now makes a drop in DryFlow filters but when I bought my cone a year ago they did not. If I was start at square one again, I would probably try a drop in filter and cutting a large portion of my stock air box away to make the intake hole as large as possible.

Brian Frank - Holy crap Brian Frank!!! Is this the Bryan Frank that went to St. Mark's and graduated in 1997? If so long time no see. Anyway the cost was minimal thanks to Powder Barons. I am not really interested in making more of them, the amount of time and labor spent working on this one for myself would far outweigh the cost of an aftermarket setup by several hundred dollars, but it was fun making it myself and the sense of personal accomplishment is priceless.

Costs were as follows...
All metal (sheet and strap with a bunch of extra) - $12
TrimLok Bulb Edge Seal (ebay) - $25
Couple of Stainless hex screws, nuts and washers - $2
Electric Metal Sheer - $37 (I don't like to count tools in the cost of a project but realistically it is something you need for this.)
Powder Coating - $30

Also unfortunately the guy I got the edge seal from only sold it in 25 foot lengths, so I had to pay for a lot more than I needed.
If anyone decides to make their own shield I will gladly sell you some edge seal for a $1 a foot, I have about 20 feet or more extra.

Jason Fritz - I agree about finding the cold air source and I have seen a cowl cutting design before on an XJ but I am not much into cutting holes in my Jeep if it isn't necessary and I would think with your design that any "cold air" advantage you are getting sucking air from the cowl is negated by the air snaking through the long tube running across your hot engine compartment. I chose to use the factory location and make a compromise between the coldest air and smoothest most direct route to my throttle body. Your design takes the cake for stealth snorkel though, if you have the intake and all other important components sealed up nice you have essentially raised you water fording level to your hood line.

I think ideally the best setup would be to cut a hole in my driver side fender well and through the fender liner. Then install some sort of medium density foam that would block water and mud from splashing into the engine bay but still allow cool air from the wheel well to pass into my enclosed intake area. But...again I am not keen on cutting sheet metal for minor if any gains. I only tried to attempt to mimic the most popular of the aftermarket for the lowest price possible.