Acrylic air intake baffle plug

 by Akoi Meexx
Preamble:
In order to follow this instructable, you must have access to the following items:
  • Acrylic
  • A drill
  • A lathe
  • Screws
  • Gouges and skews
If you don't know what any of these tools are, just get a drain plug, or have someone who does have access to these tools to make it for you. I am willing to make these for people who are interested, but I will be charging through PayPal for materials and my time, so they will run about $40 a pop for a basic plug for a 3" intake port. Send me a message if you need one made and we'll work something out.


Intro:
I (as of this instructable) drive a 96 Caprice. It's a retired cop car, and I love to tinker.

If you look under the hood of a Caprice, more often than not you'll see a big black "home plate" shaped piece of plastic on top of the engine.

This is an air baffle. Air baffles normally do a few things. First off, they quiet down the airflow a little bit (which is more noticeable when you have a turbo installed). After that, they tend to slow down the airflow into your engine. Slower airflow means it takes longer for particulates to collect and build up on your air filter, but it also means you have a little less power (generally speaking, the more air in and out of your engine, the more power you're going to get). The home plate really only serves one purpose though, to quiet out noise from the intake. There will always be debate on whether or not it robs you of performance, but even if it did, the difference would be so negligible that you probably wouldn't even notice it on a drag strip. (A good discussion on this topic can be found on the 9c1 forum post here: http://www.9c1.net/forum/index.php?showtopic=122615&hl=baffle+home%20plate+resonators)

Since I hated the look of the baffle, and I'm never one to turn away easy mods, I pulled the baffle and installed a drain plug from Home Depot ($3, if you're looking to save on coin).

It's basically two metal discs with a large rubber ring sandwiched between them, and a bolt running through to squeeze the rubber ring between the discs (causing it to expand). This worked fine, but I still wasn't pleased with the aesthetics.

Enter bullet resistant acrylic from TAP Plastics.
 
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Step 1: Mark out your circle

Using a straight edge (or whatever handy piece of flat material you have on hand), mark out lines from corner to corner on your acrylic block. Repeat on the other side. This will help you center the circle you want to draw, and help with centering the project for mounting on the lathe.

Next, measure out the diameter of your intake port that you will be plugging. Mine is a 3" intake port, so I will need to set my compass to the radius, 1 1/2". Push the point of your compass into the intersecting lines on the acrylic block, and draw out your circle. Now, add about a 1/4" to the radius measurement on your compass, we'll want a lip to prevent the plug from sinking all the way into the intake. Mark out the circle the same way. Flip the acrylic block over, and make the same circle on the other side, this (and the lines) will help you center the mounting plate on the acrylic.

Mount your plate onto the acrylic (I use a drill to make some pilot holes for the mounting screws) and jump to the next step to handle cutting off excess material.
ManlyJack says: Jun 9, 2013. 2:41 AM
Those "Air Baffles" act as a resonance chamber, which actually will increase the airflow into the engine at certain frequencies. Manufacturers work out the specific size for them to be so the air is actually being forced into the engine by resonance at a given RPM range, normally in the normal driving range. Removing them can also have a negative effect, kinda like removing the stock airbox and replacing it with a pod filter because it looks like it is much more free flowing.
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