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How to make a throttle body spacer for 1995 Jeep Cherokee

This instructable will show you how to make a throttle body spacer that you see for $80+ for your Jeep Cherokee for less than $20 and in about 3hrs.
 
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Step 1: Acquire Materials

Basically the things you will need are:

1. 1" thick aluminum plate that is roughly 100mm square
2. 1/4" End Mill that is longer than 1"
3. 1/4" Drill Bit

4. CAD/CAM software
5. CNC Machine

6. (4) 6mm x 50mm bolts
7. (3) 6mm x 40mm bolts
8. (3) 1/4" ID x 1" long steel spacer
9. (2) New Throttle body gaskets for your intake (about 2$ a piece)

The total cost from the hardware store was less than 8$.

Step 2: Make the model

In your CAD program, make the model or download mine. If you don't have a vehicle that takes this type of throttle body spacer (TBS), you can go buy a throttle body gasket and just model that and extrude it an inch. As long as you have the clearance, this should work.


Step 3: Make the Tool paths

Using your CAM software, select the correct faces for milling and the right tool speeds.

For this cut, I used the following speeds:

Feed Rate - 15 in/min
Spindle - 2400rpm

The endmill is 1/4" diameter and has 4 flutes. Normally, you shouldn't used 4 flutes for aluminum, but it works.

When using the CAM (computer aided machining) software you

1. Import or Create the model
2. Create the blank
3. Create the tool
4. Create the tool path and select the proper faces

Some tips:

** I usually choose to not use a specific corner for machining, that way I don't have to use the edge-finder.

** Adding tabs to your part will keep large cut out pieces from flying around and/or breaking the tool

After it is finished machining, use a dremel and cut the tabs off. Smooth them down and the inside will be finished.

Then use a band saw to cut out the outside dimensions. With a rough blade, this should take about a minute--pretty simple. The outside dimensions are not at all important, just as long as you don't creep into the drill holes or the center.
127ice4 months ago
What is the purpose of this spacer?
pullinsb (author)  127ice4 months ago
The theory is that the spacer provides additional volume downstream of the throttle to increase instantaneous flow through to the cylinders.
I recently learned the trick about tabs, after I sent one of my parts flying. Are you doing a full overhaul on your cherokee?
pullinsb (author)  audreyobscura1 year ago
I learned about tabs when I sent a 3/4" end mill bit across the room....luckily I wasn't in the way.

I'm not doing an overhaul on my Jeep. I ended up trading it in to buy my wife's new car--but not before I made one of these for my brother's Jeep too.

I assume you're a Jeep fan?
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