[dawrr]

I was kind of bored, so I read about a mod almost any Mustang owner can perform at little to no cost. Apparently, Ford and GM include an "air silencer" with most of their vehicles after 1987. I'm not 100% sure on the date, but many if not most cars and trucks too come with a very restrictive piece of equipment.

Now, there is much controversy over the usefulness of this piece. Some claim that the air silencer is simply a waste of material; it restricts air flow and only makes the air less turbulent and quieter. Others insist that the spiraled porting on the inside creates a venturi pressure difference, increasing air flow.

I have my own theory. Yes- The internal design does create an internal vacuum, but the difference in pressures is so minute that the air flow is barely affected. Much like a muffler, this piece allows air flow, but reduces abnormal flow (frequencies in mufflers)

So, lets compare this to an analogy. Try drinking a soda through a normal straw. Now, try it with a wide milkshake straw. Since the diameter allows for more flow volume, less pressure is required. However, work stays the same. Less stress is involved with the wider straw.

Similarly, with a consistent path to follow, the air will be less turbulent, and the backflow will be minimized. When you think 'friction' you think sandpaper. Well, solids experience friction, but fluids do too. Air experiences friction- so the less bends and torsions it is put through, the easier it will flow. The more volume of air that gets into your engine, the more power the engine will produce.

In the 2.3l Mustang, the air silencer is the shoebox-sized plastic shell between the air filter and the throttle body. In many cases, it has the Ford logo on it. Now, here is where things get complicated:

Once you have located the air silencer, remove it. Measure the intake and output diameters. If they are the same (typically 3") you are in luck. If one is different, you have a short task ahead of you.

Next, see if the inner section can be removed. If you can remove the inner section and just keep the outer shell, you can avoid a lot of work. However, the large opening will actually cause some back pressure. The goal is to have the airpath as smooth as possible.

I recommend keeping the air silencer intact and stored someplace. Next, write down the two diameters you measured. Notice that the inner diameter of the air silencer is about 1.5"

So, you start with the area of your air intake (whatever size that is) Mine (the stock one) is about 10 square inches.

Now, after the air filter, you have the first bend. Typically, it is 3" in diameter, or about 7 square inches. Next, we meet Mr. Silencer. He has a diameter of about 1.5" or 1.76 square inches. Hmm. So the air flow meets quite a bit of restriction here. Yes, the porting does 'eat up' some of that air, but the majority of the flow gets compressed, or slowed down. The turbulent air (the air that causes a 'whoosh' noise) gets pulled into the outer section of the silencer and is therefore silenced. That air could be put to better use; hence this mod.

So, you go from (square inches) 10" to 7" to 1.76" back to 7" (if the diameters are the same)

Well, what if that 1.76" is eliminated? Increasing the diameter along that stretch increases flow, and restriction is reduced. Your engine can breathe deeper.

So, how do you do it? Well, this tutorial is only meant for 2.3l owners because the air silencer takes a couple forms. So if you don’t have a 2.3l Mustang, this guide isn’t catered to you.

First, remove that air silencer by loosening the pipe clamps around the throttle body and the air filter. Remove the entire unit with both hoses still attached. Now, remove the hoses. By keeping the hoses on while you remove the unit, you eliminate cracking the air filter (if you still have the stock one).

Now, measure the intake and output diameters. Some will be 3” and 3”, while others will be 3” and 3.5”

If you have 3” 3”, realize that those 3” are outer diameters. The inner diameter of the tubing is the same size. So, you can’t simply throw a piece of 3” PVC pipe. The outer diameter of 3” PVC pipe is actually 3.5” Most plumbing pipes are measured by the inner diameter. So, I recommend using tailpipe. Go to your local auto parts store and purchase a 2’ section (at least 2’) of 3” od tailpipe. Now, measure the air silencer tip to tip. Using a hack saw and a mitre box, cut the tailpipe to the length of the air silencer. Allow about ½” of play. Now, use a file to debur the pipe. You do not want any foreign matter to be introduced to your engine. Make sure that the inside of the pipe is clean and residue free. Wrap both ends of the pipe with friction tape or electrical tape. If the tape does not adhere, wipe the pipe with alcohol first and allow it to dry. Next, attach the angled tubing. Then, reattach the whole unit to the throttle body first, and then the air filter. The throttle body is more solid than the air filter unit, so attaching the unit to the TB first allows more torsion without the risk of breaking anything.

If you have 3” 3.5”, like I do, you have another task. Go to a hardware store and purchase at least 2’ of 3” PVC and a single 3”-2” adapter (not a bushing, you need the adapter). Next, measure your air silencer length. Now, place the 3”-2” adapter to the end of the PVC. Measuring from the top of the adapter, mark the length of the air silencer on the PVC pipe. You want the overall length of your unit, including the adapter, to be the same size as your air silencer unit. I recommend wrapping both ends of PVC (the adapter and 3” end) with electrical or friction tape until they fit snugly within the tubing ends. Once the unit is together, attach the tubes and connect the 2” end to the throttle body. Then, once one end is on tightly, connect the other end to the air filter. Tighten all pipe clamps.

If you want this mod to look really nice, search online for a silhouette picture of the Mustang Logo. Print out the picture and stencil it onto the pipe. Remove the pipe (or do this before you install it) and spray-paint the pipe with the sihouette outlined with masking tape. Take your time and this turns out very nice. I found that black background with a red, blue, or gold mustang looks great. If you can find a decal, that works better. With some time and effort, this mod can really dress up your engine compartment.

So, the question on everybody’s mind is, “What effects will this provide?” Well, I’ll tell you right now: You will notice a difference. However, this also depends on what type of air silencer you have. Some are more restrictive than others. Mine, once I measured it, was 1” in inner diameter. I also noticed a throatier sound. I already have a high-performance exhaust system, and let me tell you that this mod makes quite a difference in sound. I asked my friend to listen for the difference. After hearing me drive up about ¼ mile away, she said that my car was now much louder and sounded better too.

For a really drastic improvement in sound and performance, scrap that old air filter box and install a K&N conical filter. It sounds great, really improves air flow, and coupled with your new restriction-free intake housing, you will notice quite a difference in HP. At higher speeds, my car was much more responsive, while lower speeds felt less of an improvement. Still, my car is now peppier.

I hope you found this tutorial somewhat useful. After searching for a while, I never found a tutorial specifically for 2.3L Mustang owners. Enjoy!

[mustanghelper]

I stopped reading after paragraph two sorry.

[dawrr]

Originally Posted by mustanghelper

I stopped reading after paragraph two sorry.

Aww.. Well, when I write tutorials on stuff (I've written many, many) I give the reader somewhat of a background. There's no sense in simply saying 1) Do this ; 2) Do that ; 3) Do that and this twice, repeat if necessary. The reader no knows how to perform the operations, but does not necessarily know why.

I am also a tutor for all 4 Calculus classes, (soon to be for Diffy-Q as well), Advanced Chem, and Engineering Physics. When I tutor, I don't just say, "Take the partial derivative of each component and find the unit binormal vector." NO WAY. I lead into that. I explain what a gradient is, first, then I explain what a binormal vector is, and why we are finding it. Same thing with cars (I'm not an expert on them; I know the math behind it, but the actual motions I still have to learn)

So, if you want to get to the ORDER OF OPERATIONS, go to paragraph starting with "In the 2.3l Mustang, the air silencer is the shoebox-sized plastic shell "

Enjoy..

[91BMC]

This is tricky...

The faster a fluid moves, the less pressure it has. This law is the reasoning behind airplanes ability to fly.

So, the restricting airflow DOES increase velocity, but reduces pressure.

With my minimal logic and math skills, lets figure this one out.

If you have higher pressure airflow infront of, and behind, the silencer. Inbetween these is a area of high velocity/low pressure air.

Wouldnt that cause MORE turbulence in the silencer? As the faster moving air still has to wait for the higher pressure slower air to be sucked into the engine? And until then, it has nowhere to go.

I wish I understood physics better.

[dawrr]

No, you're right...
But at high speeds, the silencer prevents the engine from breathing deep. For the air to completely stop, your engine must be idling wicked low.

[JSTANG17]

HEY DAWRR, you for got something. What would you do with the vac lines that go to the air box if you put a k&n cone airfiter on the 2.3l efi? I've removed the both silencers in front of the air box and the one you said to removed and notice a diffrence but my car will idle bad some times it idles 1,000 rpm but when it idles bad it idling from 1,000 then drops to 500 or less, sometimes it quits.
Mustang fan 4 life jstang
P.S. What kind of exhaust system you got 1muffler or 2 , or a 1in dual outlet?

[74stang2togo]

Dawrr, you're a genius... but pretty complicated, lol.

That's a really good writeup, even if it is a little long and detailed, you could easily write tech manuals for a living... or textbooks. (both pay good money)

Originally Posted by JSTANG17

HEY DAWRR, you for got something. What would you do with the vac lines that go to the air box if you put a k&n cone airfiter on the 2.3l efi? I've removed the both silencers in front of the air box and the one you said to removed and notice a diffrence but my car will idle bad some times it idles 1,000 rpm but when it idles bad it idling from 1,000 then drops to 500 or less, sometimes it quits.
Mustang fan 4 life jstang
P.S. What kind of exhaust system you got 1muffler or 2 , or a 1in dual outlet?

You can put a small screw in each, or a golf tee to simply plug them, but for a cleaner look, track the hoses back to the ports they originate at and install vacuum caps on them. They're just there to actuate the pre-heater tube's control valve, but I've found that the preheater assembly on a fuel injected 2.3 isn't even necessary. I removed the stove from the exhaust manifold when I put a cold-air intake on mine, even at 10*F it cranked right up, idled a little higher than with the preheater system, but ran like champ, I also had a 2" single pipe on mine with a Thrush Turbo Muffler, sounded fairly good (even better when I ditched the resonator and gutted the catalytic converters) and I picked up 2mpg with both mods.

[dawrr]

WOW! Thank you! I really appreciate that!
I just hope this helps someone with this project.

And my exhaust? LOL. Funny story behind that. I have a single exhaust with a Cherry Bomb Turbo Reverse-Flow muffler on it. Tomorrow I'm throwing a glasspack on it.

When I bought my Mustang, the guy had a muffler on it that was so restrictive I could barely hear my car run. I hated it. 10-31-06 the whole system fell off and I got the new system installed after the catalytic converter.

The Turbo muffler is nice, but not as loud as I wanted it to be.

At one point, I was going to simply pull off the entire exhaust system and let it straight out the catalytic converter, but then the system fell off and I decided I didn't like that.

[74stang2togo]

Originally Posted by dawrr

WOW! Thank you! I really appreciate that!
I just hope this helps someone with this project.

And my exhaust? LOL. Funny story behind that. I have a single exhaust with a Cherry Bomb Turbo Reverse-Flow muffler on it. Tomorrow I'm throwing a glasspack on it.

When I bought my Mustang, the guy had a muffler on it that was so restrictive I could barely hear my car run. I hated it. 10-31-06 the whole system fell off and I got the new system installed after the catalytic converter.

The Turbo muffler is nice, but not as loud as I wanted it to be.

At one point, I was going to simply pull off the entire exhaust system and let it straight out the catalytic converter, but then the system fell off and I decided I didn't like that.

I think you'll like the glasspack sound on the 2.3... it still sounds like a 4-banger, but you'll be stunned at how good a 4-banger can sound (especially the 2.3, simply the best little 4-cylinder engine ever built) with a glasspack if it's getting enough flow at both ends (intake and exhaust) my little '74 rumbles loud enough to shame my '75 Chevy with it's longtube headers, dual glasspacks, and 400cid engine pushing them! Plus, a quick rev-up with the 2.3 & glasspack produces a bark that'll stun everyone, it's similar to the sound of an Indy Car (no joke, especially if you really romp on it once or twice real quick and let off in neutral or park, just don't over-do it, free-revving's pretty hard on engines, but hard to avoid with a note like that!!!)