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I must be getting old... :-) DIY 2012 intake modification

42K views 108 replies 29 participants last post by  TORQUERULES 
#1 ·
I LOVE my Mustang being obnoxiously loud, but of course it isn't driven anywhere close to daily. I had a 2001 Zx3 and of course a lot of modifications because it was fun at the time. Now that is sort of old. Let's face it... a loud 4cyl kinda sucks (of course that is just my opinion).

There has been a lot of talk about a better air induction set-up on the new Focus and I have to say I am impressed with Steeda's gains with their kit, and I love the ingenuity of some of our members in doing everything from a 3 inch hose providing extra air from the bumper to taking the air cleaner lid off. But, and this may be me getting old, the noise from an open filter on this engine is obnoxious. The ONLY way it sounds good is at WOT and that is not where I spend most of my time in the Focus. This is a great breathing engine and it likes to ingest air, but unless there is a louder exhaust (and it would have to be decently loud) to offset the intake, then it is just nasty. Not even a good tone down low. Just a sick and loud boggy sound. Yuck. I want to eventually put something like the FS Stealth exhaust on my car because they have a nice deep tone, but it won't really be enough to overcome the intake. I would love to hear what the Steeda sounds like with its velocity stack design MAF housing, but I haven't had the chance.

So what this is all leading to is me thinking about how to make a "little" intake sound (you have to have a little---LOL) and get in more air without it sounding like a sick elephant stuck in the mud surrounded by crocs.

First I removed the silencer under the air box. Sounded gay. So I made a block off plate for the hole left behind because the silencer itself is gay. The tone increased, but not in a bad way. Linear and well integrated with the stock exhaust.

Then I tried the lid off the box (I have a K&N installed). Super gay. WOT was killer, but it sounded sad everywhere else. Not a good smooth tone.

So, I got to thinking about how this thing pulls air in factory form. It has two snorkels going to the box. Good. They run to the grill area at the front of the car. Good. Then there is a restrictive snorkle gathering air from the opposite side of the grille. Bad. And the opening of the grill is blocked by a piece of thin plastic that directs air away from the intake and instead to the very top of the radiator (actually mostly right over the top since the radiator gets 99.9% of its air from the bumper) with only about a 2x2" hole nowhere near the entrance of the snorkle. Very bad.

So... I got out my tools and first removed the snorkle behind the grille. This left a nice opening in the radiator support that the snorkles from the box plug into. I then removed the thin plastic shield that keeps most of the air being rammed into the grill from getting to the intake. This required some cutting, but you never notice it because it is all hidden.

So now my engine has an enclosed airbox, with two entrances for air (which are now short), and it pulls air from under the entire grill bar. All good (or at least much, much better than stock).

The sound is perfect. Smooth and linear and most people think it was meant to sound that way. The power seems improved seat of the pants (and I am very attuned to that I assure you). Nothing draumatic, but nicely noticable.

Now, before you talk about water, just remember that the stock airbox has previsions to eliminate that threat for anything other than driving through water up the the window seals. Plus, rain, etc. is minimal in that area unless you again are driving through said flood (in which case even a stock Focus could be screwed).

Before you mention heat, think about a short ram. The heat impact there is minimal (been proven) especially with a shield, and it is right by the engine and radiator. A CAI is down by the road with radiates all kinds of heat, and the filter is still open in the engine compartment (plus the extra tubing hurts power which is why a short ram usually beats a true CAI for power). I am getting air from in front of the car. Is there heat there? Yes. But where does a new Mustang draw air? Same place. You can't completely get away from heat. But, I beleive I have the best area possible to draw air from, and when moving it will only get better.

So, that is my littlle DIY mod for the month. Wish I had pics, but it is almost impossible to get good shots down in there. I tried.
 
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#5 ·
I don't doubt you at all, and not to play devils advocate as I am in the market for an intake (I have a really loud exhaust), but wouldn't highly paid ford engineers figure this out? Maybe I am contradicting myself as they build these things targeted to the masses who probably want nice quiet cars and don't care about power. I dunno. I have been reading too much about how efficient (ram air ish design) our stock intake is and how steeda rigs dynos, etc. I guess I am considering my options here
 
#6 ·
The ford designers care about noise levels, emissions, mass market stuff, you could do this mod and still get an intake, this just changes snorkel stuff
 
#7 ·
Duffman, I completely understand. The factory system is actually pretty good. It is probably the best compromise Ford engineers could come up with from a power, reliability, and NVH standpoint. It is easy to open up a Mustang intake. Especially the sweet new 5.0. To an enthusiast the sound of a 4valve V8 is music. But the Focus ( non-ST [the ST's turbo will change the game for what they will do from an NVH standpoint {more leeway}]) is a car for the masses that has evolved from being just plain fun and economical, to a fun, luxurious ( for its segment), and economical car. Thus the compromise that is the factory intake. The engineers did their best with the targets they were given. What I have did gives the Focus a little growl. Nothing loud, but noticeable. It is really pretty nice. But I assure you that some liberal douche from Motor Trend would complain. Thus the ultra-quiet factory compromise.
 
#8 ·
^Nice triple enclosed quote [hihi]. Even when drunk I only double bracket quote, lol (and that's usually in a non meaningful non informative way)

I agree with the two posts above me though which is why i am still sitting on my stock intake. I'm struggling still with with dropping $2-300 on an intake that may or may not benefit me with more gains than pure sound awesomeness. I have the FS Werks race exhaust and it is loud and menacing which I was looking for and may give me a few horses? I always considered the intake the more performance oriented mod as opposed to the sound exhaust provides personally. Good to have a board where this kind of debate is possible I suppose
 
#9 ·
Yea, the brackets did get excessive didn't they? [:p]

I believe an intake and exhaust together would make fantastic gains on this car. Even more so when you can tune with SCT and add a header and take off the cat. This engine has ALOT of potential. Think about it... DI, 12.1 compression, TI-VCT, excellent head flow... I see nice power N/A and F/I (the ST) coming in the future for these engines.
 
#55 ·
Hey Matt-
Do you have links to these pics?--I can't seem to make them large enough to read and see what you actually did.
Thanks
 
#17 ·
You ever hear the sound of a Carter 625 4bbl atop a Shelby medium riser on a 302? If it had a silencer, you wouldn't.

All it does is keep you from hearing the in-rush of air by having baffles and ported chambers(Helmholtz resonators) in the flow path.

Remove silencer, and silence is removed. Now, if a tree falls in the forest...
 
#22 ·
Nice little write up man. Just went out and did this.

I have the Steeda CAI so I can't comment on how the stock airbox sounded with it but strangely this did seem to clean up the sound for the Steeda unit. Could be in my head though.

Interesting hose idea. Definitely a bit easier than newmission's. Although if you aren't planning to add that to the bottom of the airbox I'll be extra interested in what your plans are.
 
#24 ·
Added to the bottom of my air box. For the opening in the side grill, I just cut it n half and left a nice opening into the inlet. I can also use the piece I took out to block it off again if some weird need to do so arises.

Sounds about the same as my original mod. ONLY has more sound at WOT, and still it does not overpower anything or sound ricey.

Feels good too.
 
#30 ·
ok, ill try and measure as well, but 24" would be a good length for me to try and do a 1 foot straight pipe and a 45 degree angle bent pipe.
 
#32 ·
yeah the tubing would be easier to work with, I am just building an aluminum air box and going all aluminum should be able to get welded by my installation place.
 
#34 · (Edited)
the hard part I think is the top stock snorkel, it is a weird shape, i might just pull it and put my own hose from the front and see if that works, the stock box is 8X10 where the snorkel connects and 8X8 the rest of the box, I think it is 7" vertically but i didnt measure that as accurately.

Do you have an Obd II reader? I am curious about the MAF readings, too much air could cause the sensor to not report properly, so I wonder if newmission's mod, plus yours forces a lot of air through.
 
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