My modified factory intake
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Joined: Feb 2015
Posts: 65
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My modified factory intake
Yes, this is not a new idea. I actually have Acurazine to thank for the inspiration! This is just a short documentation on how I went about modding the factory intake (or really just removing the resonator). I also like to share what I learn, so hopefully I can provide some information that isn't already out there, some where ...
So the first thing I wanted to do was pull the front bumper off and scope out the situation. Let me apologize right now and say I didn't take pics every single step of the way, I only really had the intention of sharing the measurements I came up with. I think most of you guys know what to expect to see when you pull the front bumper off by now anyway
Oh, and there's another attachment point of the factory intake pipe to the body, directly underneath the batter tray, that I haven't seen ANYONE mention. I'm sitting here trying to yank this whole thing out and it was driving me nuts! Ended up bending the hell out of said bracket (useless afterward).
Ok, so- the opening at the bottom of the filter box is a sort of oval shape, but as a perfect circle it would measure 4.5" in diameter. Ideally, if you wanted to secure a coupler here you would want a 4.5" clamp, but these 4" clamps from Spectre worked out fine with a small bit of adjustment to spare.
Why use clamps here? I don't know, maybe I'm just paranoid. But there won't be anything supporting the weight of the intake neck dipping down into the bumper and the bell mouth I plan to attach at the end of it. As it is this rubber coupler makes this attachment kind of loosely stock, and yes the resonator box is heavy but it is bolted to the body.
I did have a couple of considerations at this spot. Replace rubber coupler with 4.5" silicone coupler. Replace factory intake neck with 4"~4.5" straight intake pipe. But the area below the headlight to the mouth on the filter box isn't really a straight shot, and in the end I think the factory neck is already optimized for this space. Which means the factory rubber coupler is already the perfect shape to mate the neck to the filter box. Reduce reuse recycle. Another note on the factory resonator: I don't know how you guys are removing the neck from the resonator if you are, because that damn thing is impenetrable. So I took a saw to it and cut it flush to the box. Then I sanded the opening of the neck flat and smoothed it all out.
Right where the neck meets the resonator box the intake pipe is just about 3.5". Everywhere that the factory piping is close to round and not some other odd shape it's about 3.5". That's where these bad boys come into play:
The result:
Just a few final details. There's a little ridge right in the center of that 3.5" coupler. Which is cool so that you know you're joining two pipes an equal amount, not so cool when said ridge protrudes into the air path- defeating the purpose of using a funnel to smoothen the air flow. No problem though, trimmed it just enough to not interrupt flow. The 3.5" silicone coupler is a tight fit on the factory neck- but it will work with some persuasion.
You can see inside the neck where I did some light sanding. Rough looking, but smooth to the touch.
More shots:
I also changed the grounding location to get the wire loom away from the funnel. It's hard to tell but the funnel is a good 1/2"~1" away from the body.
That's pretty much it guys. I can't say whatever minuscule performance increase this may have provided, mainly because the car has been down for a week. I had to get the measurements first, order the parts, and wait for them to come in. I did it mainly for sound, but also to know (or feel like) I've optimized what was already there, at least in my own mind, and that should be good enough for me to stop considering an aftermarket intake system, which I've been reeeeally thinking about. Plus the filter will be easier to change.
The sound is mostly noticeable at or near WOT, which is pretty much the established expectation, but performance wise I would say some of the pull at part throttle seems a bit more 'effortless' I guess you could say. Gear kick downs definitely sound more violent, especially a really hard kick down you can hear the intake pretty good. Adds a little bit more aural rush to acceleration, I like it.
Spectre 4" Clamps - $5.99
Spectre 3.5" Coupler (w/ clamps) - $9.99
Blox Racing 3.5" Velocity Stack - $34.99
My left and right fog lights plug into different style "boxes" ... almost like one of them was replaced at some point. They don't seem to illuminate any differently from each other though. Just thought that was weird.
So the first thing I wanted to do was pull the front bumper off and scope out the situation. Let me apologize right now and say I didn't take pics every single step of the way, I only really had the intention of sharing the measurements I came up with. I think most of you guys know what to expect to see when you pull the front bumper off by now anyway
Oh, and there's another attachment point of the factory intake pipe to the body, directly underneath the batter tray, that I haven't seen ANYONE mention. I'm sitting here trying to yank this whole thing out and it was driving me nuts! Ended up bending the hell out of said bracket (useless afterward).
Ok, so- the opening at the bottom of the filter box is a sort of oval shape, but as a perfect circle it would measure 4.5" in diameter. Ideally, if you wanted to secure a coupler here you would want a 4.5" clamp, but these 4" clamps from Spectre worked out fine with a small bit of adjustment to spare.
Why use clamps here? I don't know, maybe I'm just paranoid. But there won't be anything supporting the weight of the intake neck dipping down into the bumper and the bell mouth I plan to attach at the end of it. As it is this rubber coupler makes this attachment kind of loosely stock, and yes the resonator box is heavy but it is bolted to the body.
I did have a couple of considerations at this spot. Replace rubber coupler with 4.5" silicone coupler. Replace factory intake neck with 4"~4.5" straight intake pipe. But the area below the headlight to the mouth on the filter box isn't really a straight shot, and in the end I think the factory neck is already optimized for this space. Which means the factory rubber coupler is already the perfect shape to mate the neck to the filter box. Reduce reuse recycle. Another note on the factory resonator: I don't know how you guys are removing the neck from the resonator if you are, because that damn thing is impenetrable. So I took a saw to it and cut it flush to the box. Then I sanded the opening of the neck flat and smoothed it all out.
Right where the neck meets the resonator box the intake pipe is just about 3.5". Everywhere that the factory piping is close to round and not some other odd shape it's about 3.5". That's where these bad boys come into play:
The result:
Just a few final details. There's a little ridge right in the center of that 3.5" coupler. Which is cool so that you know you're joining two pipes an equal amount, not so cool when said ridge protrudes into the air path- defeating the purpose of using a funnel to smoothen the air flow. No problem though, trimmed it just enough to not interrupt flow. The 3.5" silicone coupler is a tight fit on the factory neck- but it will work with some persuasion.
You can see inside the neck where I did some light sanding. Rough looking, but smooth to the touch.
More shots:
I also changed the grounding location to get the wire loom away from the funnel. It's hard to tell but the funnel is a good 1/2"~1" away from the body.
That's pretty much it guys. I can't say whatever minuscule performance increase this may have provided, mainly because the car has been down for a week. I had to get the measurements first, order the parts, and wait for them to come in. I did it mainly for sound, but also to know (or feel like) I've optimized what was already there, at least in my own mind, and that should be good enough for me to stop considering an aftermarket intake system, which I've been reeeeally thinking about. Plus the filter will be easier to change.
The sound is mostly noticeable at or near WOT, which is pretty much the established expectation, but performance wise I would say some of the pull at part throttle seems a bit more 'effortless' I guess you could say. Gear kick downs definitely sound more violent, especially a really hard kick down you can hear the intake pretty good. Adds a little bit more aural rush to acceleration, I like it.
Spectre 4" Clamps - $5.99
Spectre 3.5" Coupler (w/ clamps) - $9.99
Blox Racing 3.5" Velocity Stack - $34.99
My left and right fog lights plug into different style "boxes" ... almost like one of them was replaced at some point. They don't seem to illuminate any differently from each other though. Just thought that was weird.
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Advanced
Joined: Feb 2015
Posts: 65
Likes: 18
Thanks guys, I think the normal filter can flow enough cfm to support the motor's needs. I do think however that an aftermarket drop in would probably offer less resistance to the incoming air, making it feel more responsive. But at this point in time I am leaning toward filtration over flow. I will say that now being able to hear the tone changes from the intake manifold opening up and then vtec (yO!) has definitely made it worth it!
Last edited by 3FIFTY'07TL; Jan 15, 2016 at 04:50 PM.
